CPP 301 (Updated) Agriculture PDF

1 What is Agriculture?     Agriculture is the most important human economic activity. Agriculture is the activity of man for the production of food, fiber, fuel, etc. by the optimum use of terrestrial resource i.e. land & water. Agriculture is the backbone of most developing nations such as Nige...

1 What is Agriculture?     Agriculture is the most important human economic activity. Agriculture is the activity of man for the production of food, fiber, fuel, etc. by the optimum use of terrestrial resource i.e. land & water. Agriculture is the backbone of most developing nations such as Nigeria, India, Malaysia Economy. Agriculture is a very broad term encompassing all aspects of crop production, livestock farming, fisheries, forestry, etc. Definition of Agriculture:    The word agriculture comes from the Latin words ager, means the soil & cultura, means cultivation. “Agriculture can be defined as the cultivation and/or production of crop plants or livestock products.” Agriculture includes Crop Production, Animal Husbandry & Dairy Science, Agriculture Chemistry & Soil Science, Horticulture, Agric. Economics, Agric. Engineering, Botany, Plant Pathology, Extension Education and Entomology, which develops its separate and distinct branches of agriculture occupying now a days place in several Agric. Universities in the country. Agriculture can be termed as a science, an art & business altogether = Agricultural Science Science: Involves the manipulation of the biological component of the plant and animal (genetic component along with the environment) to provide new and improved strain of crop and animal with the help of the knowledge of breeding and genetics, modern technology of dairy science. Art: because it is the management whether it is crop or animal husbandry. Commerce (Business): the entire agric. produce is linked with marketing, which brings in the question of profit or loss. Conventional Agriculture:  “Conventional Agriculture is the term for predominant farming practices and systems of crop production adapted by farmer in a particular region” Scope of Agriculture Nearly 67% of Nigerian’s population lives in villages. The occupation of villagers is strictly agriculture and usually in small holding. Agriculture is the dominant sector of our economy before the adventure of the crude oil & contributes in various ways such as: 1 2     National Economy: The agricultural sector has contributed positively and consistently to economic growth in Nigeria, reaffirming the sector’s importance in the economy. In 1990 – 91, agriculture contributed 31.6% of the National Income of India, while manufacturing sector contributed 17.6%. It is substantial than other countries for example in 1982 it was 60 % in Nigeria 34.9%, in India against 2% in UK, 3% in USA, 4 % in the Canada. It indicated that the more the advanced stage of development the smaller is the share of agriculture in National Income. Total Employment: Around 65% population is working & depends on agriculture and allied activities. Nearly 70% of the rural population earns its livelihood from agriculture and other occupation allied to agriculture. In cities also, a considerable part of labor force is engaged in jobs depending on processing & marketing of agricultural products. Industrial Inputs: Most of the industries depend on the raw material produced by agriculture, so agriculture is the principal source of raw material to the industries. The industries like cotton textile, jute, paper, sugar depends totally on agriculture for the supply of raw material. The small scale and cottage industries like handloom and power loon, ginning and pressing, oil crushing, rice husking, sericulture fruit processing, etc. are also mainly agro based industries. Food Supply: During this year targeted food production was 198 million tons & which is to be increased 225 million tons by the end of this century to feed the growing population. India, thus, is able to meet almost all the need of its population with regards to food by develop intensive program for increasing food production.  State Revenue: Agriculture is contributing the revenue by agriculture taxation includes direct tax and indirect tax. Direct tax includes land revenue, cases and surcharge on land revenue, ceases on crops & agric. income tax. Indirect tax induces sales tax, custom duty and local octri, etc. which farmer pay on purchase of agriculture inputs.  Trade: Agriculture plays and important role in foreign trade attracting valuable foreign exchange, necessary for our economic development. The product from agriculture based industries such as jute, cloth, tinned food, etc. contributed to 20% of our export. Around 50 % of total exports are contributed by agric sector. Indian agriculture plays and important role in roads, rails & waterways outside the countries. Indian in roads, rails and waterways used to transport considerable amount of agric produce and agric based industrial products. Agric products like tea, coffee, sugar, oil seeds, tobacco; spices, etc. also constitute the main items of export from India. Importance of agriculture in Nigeria Many Nigerian households grow different types crops and depend on livestock farming. What is agriculture in Nigeria today, and what role does it play in economic growth? 2 - main source of food provision. - valuable contributor to Nigerian GDP (gross domestic product). - major source of foreign exchange. - major source of raw material for different industries. 3 The contribution of the agricultural sector to the Nigerian economy in 2010-2017 averaged 3.7 billion Naira. Experts indicate that this is about 40 percent of the GDP and this figure doesn’t change much year after year. Of course, sometimes the numbers are lower and sometimes, they are much higher but the average records show stable constant growth. Agriculture business in Nigeria Nigeria has many amazing natural resources. Still, the high GDP (compared to many other African countries) doesn’t guarantee low poverty rate. A large number of Nigerians still live below the poverty line. While many citizens are employed in the agricultural sector, large numbers of Nigerians are still unemployed. Only about the third of all the arable lands are actually cultivated. The development of the agricultural business is extremely important to the country. It can solve many current problems and improve the standard of living of millions of ordinary Nigerians. Here is how the new projects, farms, and businesses in the agricultural sector can be useful to the economy: Help to turn the focus of the economy from importation to exportation of the raw materials and food. Help create new jobs and reduce the level of poverty. Simplify life in urban and rural areas causing less migration between these areas. Help develop better infrastructure for moving products across Nigeria. Attract foreign investments into Nigeria. The importance of developing agricultural businesses and providing all the necessary conditions for local farmers and foreign investors in endless. It’s up to the government to help develop this important sector of the economy and educate potential farmers as well as already established farmers on new and easier farming methods and the types of crops that bring higher revenue. Note: The sector needs intervention from the government. It needs innovation, capital, high skilled labor, effective transportation/distribution network and more. Only these changes can boost the agricultural sector's production capacity for local consumption and export. You can see how important agriculture is for the Nigerian economy and how important it is for government to invest more into the development of this sector. No country can survive without agriculture, either as an income generating sector of the economy or simply as a domestic food production sector. What is Agronomy by definition? Agronomy (from Ancient Greek agrós "field" and nómos "law") is the science and technology of producing and using plants for food, fuel, fiber, and land reclamation. It can also be defined as the branch of agriculture that deals with the principles and practices of soil management and crop production. Agronomy has come to 3 4 encompass work in the areas of plant genetics, plant physiology, meteorology, and soil science. It is the application of a combination of sciences like biology, chemistry, economics, ecology, earth science, and genetics. Agronomists of today are involved with many issues, including producing food, creating healthier food, managing the environmental impact of agriculture, and extracting energy from plants. Agronomists often specialize in areas such as crop rotation, irrigation and drainage, plant breeding, plant physiology, soil classification, soil fertility, weed control, and insect and pest control. CHARACTERISTICS OF ARABLE FARMING IN NIGERIA 1. SIZE OF FARMS: Farms are generally small in size, sometimes over 0.5-5 hectares the farmers are small holder farmers. 2. LABOUR: Uses a large labour force, hired labour, labour mainly seasonal (mainly during planting and harvesting time). 3. Crop Production is seasonal 4. PURPOSE: Mainly plant crop for local consumption 5. RELIEF OF LAND is undulating either there are valleys or hill that prevent for easy movement of machinery 6. LAND PREPARATION TECHNIQUE/TOOLS USED they normally use hoes and cutlasses hence the lad are to be cleared is usually small 7. There is little or lack of credit facilities 8. Chemicals such as fertilizer, herbicide, pesticides, fungicides. Uses machinery such as combine harvesters, crawlers, tractors, and ploughs to speed up planting and harvesting time. 9. METHOD OF FARMING Practices multiple cropping cultivation of several crops eg. Sugar cane, bananas. HISTORICAL BACKGROUND OF FARMING IN NIGERIA Nigeria is very blessed with agricultural resources, a large expanse of land estimated at 91 million hectares (1990) of which 81 million hectares are arable. Most parts of the country experience rich soil, well distributed rainfall, not to mention the warm year-round temperatures. And 18 million hectares of land classified as permanent pasture, for livestock production. Agriculture has its place in the history of the nation, this is the reason for the 'green' in the flag, and the progressive roles it has played; serving as the major 4 5 source of livelihood to over 75% of the population. The agricultural history of Nigeria is intertwined with its political history. This can be assessed from the precolonial, colonial and post-colonial periods. THE PRE-COLONIAL AND COLONIAL PERIODS Long before the advent of Nigeria's colonization, our ancestors were sustained primarily on farming as the major occupation with the use of crude implements compared to what is obtained today. Yet, they produced enough food crops to feed themselves like most other Africans and also produced cash crops which were used for trade by barter system, across the Trans Saharan trade to the end of the Atlantic trade. They responded accordingly to the demands of their time, the limitations notwithstanding. The period of the colonial administration in Nigeria, 1861-1960, was punctuated by rather ad hoc attention to agricultural development. During the era, considerable emphasis was placed on research and extension services. The first notable activity of the era was the establishment of the Department of Botanical Research in 1893 in the former Western Nigeria; saddled with the responsibility of conducting research in Agriculture. In 1905, the British Cotton Growers Association acquired 10.35 square kilometers of land at the site now called Moor Plantation, Ibadan for growing cotton to feed the British Textile Mills. In 1910, Moor Plantation, Ibadan became the headquarters of the Department of Agriculture in Southern Nigeria, and a Department of Agriculture was established in the North in 1912. In 1921, a unified Department of Agriculture was formed in Nigeria, after the amalgamation of the North and the South. The major policy of the Central Department of Agriculture was to increase production of export crops for the British market which was ready to absorb it for its industrial growth. Extension activities were therefore directed towards increasing efficiency in crop production and marketing. Regulations were made to set and enforce standards in export crop production. Under the colonial government, livestock which were predominantly nomadic got a fair share of development with interest directed at the health and hygiene of the domesticated cattle. Thus, the Nigerian Veterinary Department was established in 1914 with its headquarters at Zaria. In 1924, a small veterinary laboratory was established in Vom for the production of rinderpest serum. 5 6 Deliberate efforts at developing the country's fisheries can be said to date back to the Second World War when, because of the naval blockade of the high seas, the then Colonial Administration decided to develop the country's local resources, including fisheries. A fisheries organization was established in 1941 as a Fisheries Development Branch of the Agricultural Department of the Colonial Office and a Senior Agricultural Officer was appointed to conduct a survey of the industry and its possibilities. The headquarters was sited at Apese village and later at Onikan in Lagos, from where, assisted by a part-time voluntary officer, preliminary experiments in fish culture in brackish water ponds at Onikan were carried out and surveys were conducted on the canoe fisheries of Apese village and Kuramo waters around Victoria Island, Lagos. The colonial period also witnessed the establishment of the Niger Agricultural Project in 1949 with the aims of producing groundnut for export and guinea-corn for local consumption. It was also meant to relieve world food shortage, demonstrate better farming techniques and increase productivity of Nigeria’s agriculture. The project was sited near Mokwa (Niger state) at an area which was suitable for mechanized food crop production. THE POST-COLONIAL PERIOD New policies were formulated in the post-independence era to actualize more equitable growth in agriculture. The earlier surplus extraction policies were quickly translated into the pursuit of an export-led growth. This led to the demarcation of the country into the Western Region (cocoa), Northern Region (groundnut) and Eastern Region (oil palm). The 1962-1968 development plans was Nigeria’s first national plan. Among several objectives, it emphasized the introduction of more modern agricultural methods through farm settlements, co-operative (nucleus) plantations, supply of improved farm implements (e.g. hydraulic hand presses for oil palm processing) and a greatly expanded agricultural extension service. Some of the specialized development schemes initiated or implemented during this period included: · 6 Farm Settlement Schemes 7 · National Accelerated Food Production Programme (NAFPP), launched in 1972. There were also a number of agricultural development intervention experiments, notably Operation Feed the Nation, launched in 1976; River Basin and Rural Development Authorities, established in 1976; Green Revolution Programme, inaugurated in 1980 The World Bank-funded Agricultural Development Projects (ADP). While each of the above programmes sought to improve food production, the ADPs represented the major practical demonstration of the integrated approach to agricultural development in Nigeria. Owing to the oil boom in the 1970s, Agriculture assumed a downward trend. Available data show that at independence in 1960 the contribution of agriculture to the GDP was about 60%, which is typical for developing agrarian nations. However, this share declined over time to only about 25% between 1975 and 1979. Between 1970 and 1982, agricultural production stagnated at less than one percent annual growth rate, at a time when the population growth was between 2.5 to 3.0 per cent per annum. There was a sharp decline in export crop production, while food production increased only marginally. Thus, domestic food supply had to be augmented through large imports. The food import bill rose from a mere N112.88m annually during 1970 - 1974 to N1, 964.8m in 1991. The years since the early 1960s have also witnessed the establishment of several agricultural research institutes and their extension research liaison services. Some of the major institutions are: 1. Agricultural Extension and Research Liaison Service (AERLS) at the Ahmadu Bello University, Zaria established in 1963 2. The International Institute of Tropical Agriculture (IITA) established in 1967 7 8 3. International Livestock Centre for Africa (ILCA). In an attempt to address the dwindling resources accrued from Agriculture, successive government implemented programs aimed at increasing food production and reviving Agriculture. These are: National Accelerated Food Production Programme (NAFPP): was an agricultural extension programme initiated in 1972 by the Federal Department of Agriculture during General Yakubu Gowon’s regime. The programme focused on bringing about a significant increase in the production of maize, cassava, rice and wheat in the Northern states through subsistent production within a short period of time. The programme was designed to spread to other states in the country after the pilot stage that was established in Anambra, Imo, Ondo, Oyo, Ogun, Benue, Plateau and Kano states. Operation Feed the Nation (OFN): This programme evolved on 21st May 1976 under the military regime of General Olusegun Obasanjo. The programme was launched in order to bring about increased food production in the entire nation through the active involvement and participation of everybody in every discipline thereby making every person capable of partly or wholly feeding him or herself. Under this programme every available piece of land in urban, sub-urban and rural areas was meant to be planted while government provided inputs and subsidies (like agrochemicals, fertilizers, improved variety of seed/seedlings, day old chicks, machetes, sickles, hoes etc) freely to government establishments. Individuals received these inputs at a subsidized rate. The River Basin Development Authority (RBDA): River Basin Development Decree was promulgated in 1976 to establish eleven River Basin Development Authorities (RBDAs) (Decree 25 of 1976). The initial aim of the authorities was to boost economic potentials of the existing water bodies particularly irrigation and fishery with hydroelectric power generation and domestic water supply as secondary objectives. The objective of the programme was later extended to other areas most importantly to production and rural infrastructural development. The Green Revolution: Green Revolution was a programme inaugurated by Shehu Shagari in April 1980. The programme was aimed at increasing production of food and raw materials in order to ensure food security and self-sufficiency in basic staples. Secondly, it aspired to boost production of livestock and fish in order to 8 9 meet home and export needs and to expand and diversify the nation’s foreign exchange earnings through production and processing of export crops. The federal government provided agrochemicals, improved seeds/seedlings, irrigation system, machine (mechanization), credit facilities, improved marketing and favorable pricing policy for the agricultural products. The Nigerian Agricultural Land Development Authority (NALDA): This was established in 1992. The authority aims at giving strategic public support for land development, assisting and promoting better uses of Nigeria’s rural land and their resources, boosting profitable employment opportunities for rural dwellers, raising the level/standard of living of rural people, targeting and assisting in achieving food security through self-reliance and sufficiency. National Fadama Development Project (NFDP): The first National Fadama Development Project (NFDP-1) was designed in the early 1990s to promote simple low-cost improved irrigation technology under World Bank financing. The main objective was to sustainably increase the incomes of the Fadama users through expansion of farm and non-farm activities with high value-added output.The programme covered twelve states of Adamawa, Bauchi, Gombe, Imo, Kaduna, Kebbi, Lagos, Niger, Ogun Oyo, Taraba including the Federal Capital Territory (FCT). The program adopted community driven development approach with extensive participation of the stakeholders at early stage of the project. This approach is in line with the policies and development strategies for Nigeria which emphasize poverty reduction, private sector leadership and beneficiary participation. Overall appraisal of the first and second phases of the project; show remarkable success, hence the invention of the current third phase. National, Special Programme on Food Security (NSPFS): This Programme was launched in January 2002 in all the thirty six states of the federation during the Olusegun Obasanjo’s regime. The broad objective of the programme was to increase food production and eliminate rural poverty. Other specific objectives of the programme were: assisting farmers in increasing their output, productivity and income; strengthening the effectiveness of research and extension service training and educating farmers on farm management for effective utilization of resources; supporting governments efforts in the promotion of simple technologies for selfsufficiency; consolidating initial efforts of the programme on pilot areas for maximum output and ease of replication; consolidating gain from on-going for continuity of the programme and consequent termination of external assisted programmes and projects. 9 10 Root and Tuber Expansion Programme (RTEP): RTEP was launched on 16th April 2003 under Olusegun Obasanjo’s administration. It covers 26 states and was designed to address the problem of food production and rural poverty. At the local farmer’s level, the programme hopes to achieve economic growth, improve access of the poor to social services and carry out intervention measures to protect poor and vulnerable groups. At the national level the programme is designed to achieve food security and stimulate demand for cheaper staple food such as cassava, garri, yam, potato etc as against more expensive carbohydrate such as rice. Small holder farmers with less than two hectares of land per household were the targets of the programme while special attention is being paid to women who play a significant role in rural food production, processing and marketing. RTEP also targets at multiplying and introducing improved root and tuber varieties to about 350,000 farmers in order to increase productivity and income. PRESENT DAY Agricultural Transformation Agenda (ATA): In 2011 the government of Nigeria, launched the Agricultural Transformation Agenda, with the aim of changing the perception about agriculture as a development issue instead of pure business. The vision in the transformation strategy is to achieve a hunger-free Nigeria through an agricultural sector that drives income growth, accelerates achievement of food and nutritional security, generates employment and transforms Nigeria into a leading player in global food markets to grow wealth for millions of farmers. In order to achieve this vision, the value chain approach has been in use. Fertilizer procurement and distribution, marketing institutions, financial value chains and agricultural investment framework are poised for a change using this approach. Ironically, the issues and challenges have not changed much since the dawn of agriculture in Nigeria. Majority of farmers (more than 65%) still use the crude method of farming; Storage ideas and facilities have not improved much and thus losses incurred from postharvest handling are still very high; Infrastructure development has not progressed to meet the current challenges, resulting in 10 11 stagnation of processes and logistical nightmare; Access to markets has remained a recurring headache making the idea of Farming very unattractive to most people. Beyond all of this the fact remains that, Nigeria’s Agriculture Sector has enormous potential, with an opportunity to grow output by 160% from USD 99 billion at present to USD 256 billion by 2030(depending on who you ask). This growth potential comes from the ability to; 1. Increase yield to 80% -100% of benchmark countries. 2. Shift 20% of production to higher value crops. Opportunities highlighted at SENCE Agric’s Agriculture Fair of March 2012 showed that Nigeria faces a large and growing global agricultural market. The rising commodity prices, growing demand for food and opportunities in bio fuel as safe sources of alternative fuel all present significant opportunities for Nigeria. In summary Agriculture has had a long history in Nigeria albeit a not so successful one but the future is great and the right people need to be involved to move it away from rhetoric to a life giving, money making venture for the good of man and country. 11 Arable farming is a type of crop production that produces a wide range of annual crops. This means that the crop life cycle, from germination to seed production, is complete within one year.... Grain crops; cultivated grasses and millets grown for their edible starch grains (wheat, maize, rice, barley, proso millet) Agronomy (from Ancient Greek agrós "field" and nómos "law") is the science and technology of producing and using plants for food, fuel, fiber, and land reclamation. It can also be defined as the branch of agriculture that deals with the principles and practices of soil management and crop production. Agronomy has come to encompass work in the areas of plant genetics, plant physiology, meteorology, and soil science. It is the application of a combination of sciences like biology, chemistry, economics, ecology, earth science, and genetics. Agronomists of today are involved with many issues, including producing food, creating healthier food, managing the environmental impact of agriculture, and extracting energy from plants. Agronomists often specialise in areas such as crop rotation, irrigation and drainage, plant breeding, plant physiology, soil classification, soil fertility, weed control, and insect and pest control. As Breeder: This area of agronomy involves selective breeding (Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, (A cultigen (from the Latin cultus – cultivated, and gens – kind) is a plant that has been deliberately altered or selected by humans; it is the result of artificial selection. These man-made or anthropogenic plants are, for the most part, plants with commercial value used in horticulture, agriculture or forestry). or cultivars The term cultivar[nb 1] most commonly refers to an assemblage of plants selected for desirable characters that are maintained during propagation. More generally, cultivar refers to the most basic classification category of cultivated plants in the International Code of Nomenclature for Cultivated Plants (ICNCP). Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids. Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or noncommercial professionals: major crops are usually the provenance of the professionals.) of plants to produce the best crops under various conditions. Plant breeding has increased crop yields and has improved the nutritional value (Nutritional rating systems are methods of ranking or rating food products or food categories to communicate the nutritional value of food in a simplified manner to a target audience. Rating systems are developed by governments, nonprofit organizations, or private institutions and companies.) of numerous crops, including corn, soybeans, and wheat. It has also led to the development of new types of plants. For example, a hybrid grain called triticale was produced by crossbreeding rye and wheat. Triticale contains more usable protein than does either rye or wheat. Agronomy has also been instrumental in fruit and vegetable production research. Agronomists as Biotechnologist: use biotechnology to extend and expedite the development of desired characteristic. Biotechnology is often a lab activity requiring field testing of the new crop varieties that are developed. In addition to increasing crop yields agronomic biotechnology is increasingly being applied for novel uses other than food. For example, oilseed is at present used mainly for margarine and other food oils, but it can be modified to produce fatty acids for detergents, substitute fuels and petrochemicals. Agronomists as Soil Scientist: study sustainable ways to make soils more productive and profitable throughout the world. They classify soils and analyze them to determine whether they contain nutrients vital to plant growth. Common macronutrients analyzed include compounds of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. Soil is also assessed for several micronutrients, like zinc and boron. The percentage of organic matter, soil pH, and nutrient holding capacity (cation exchange capacity) are tested in a regional laboratory. Agronomists will interpret these lab reports and make recommendations to balance soil nutrients for optimal plant growth Soil conservation In addition, agronomists develop methods to preserve the soil and to decrease the effects of erosion by wind and water. For example, a technique called contour plowing may be used to prevent soil erosion and conserve rainfall. Researchers in agronomy also seek ways to use the soil more effectively in solving other problems. Such problems include the disposal of human and animal manure, water pollution, and pesticide build-up in the soil. As well as looking after the soil for future generations to come, such as the burning of paddocks after crop production. As well as pasture [management] Techniques include no-tilling crops, planting of soil-binding grasses along contours on steep slopes, and contour drains of depths up to 1 metre Agroecology Agroecology is the management of agricultural systems with an emphasis on ecological and environmental perspectives. This area is closely associated with work in the areas of sustainable agriculture, organic farming, and alternative food systems and the development of alternative cropping systems. Theoretical modeling Theoretical production ecology tries to quantitatively study the growth of crops. The plant is treated as a kind of biological factory, which processes light, carbon dioxide, water, and nutrients into harvestable products. The main parameters considered are temperature, sunlight, standing crop biomass, plant production distribution, and nutrient and water supply. The Practice That Marks the Beginning of Arable Crop Life Cycle Arable farming is a type of crop production that produces a wide range of annual crops. This means that the crop life cycle, from germination to seed production, is complete within one year. Depending on the type of use, there are a few different types of arable crops. These include:  Grain crops; cultivated grasses and millets grown for their edible starch grains (wheat,      maize, rice, barley, proso millet) Pulse crops; edible seeds from the legume family, high in protein (lentil, beans, peas) Oil seed crops; grown for the oil extraction from the seeds (rapeseed, soybean, sunflower) Forage crops; crops used for animal feed, fresh or preserved (cowpea, clovers,) Fiber crops; crops grown for fiber yield (cotton, jute, flax) Tuber crops; crops whose edible portion is a short thickened underground stem (potato, elephant yam) Sowing or Planting of Arable Crops? Since arable farming encompasses a wide range of different crops, we have to consider the sowing, as well as planting. There is a big difference between these two farm practices. For instance, sowing is a practice that involves putting seeds into the soils. While, planting means putting an already live plant into the soil. The plant can be grown by a farmer or purchased from a nursery. An additional difference between sowing and planting is in the crop spacing and density. For instance, sowing row spacing is usually smaller than in planting. On the other hand, crop density is higher than in the crops that are sown. However, a common feature of both practices is that each practice can be done manually or with the use of machinery. Sowing and Planting Types in Arable Farming There are a few methods of sowing and planting in arable farming, including:       Broad casting; the sowing practice that scatters the seeds by hand all over the prepared field Drilling or line sowing; sowing of crops with the use of machinery Dibbling; sowing method of placing the seeds at cross marks made in the field; this practice is done manually using a dibbler Putting seeds behind the plough; a practice that involves the dropping of seeds manually behind the plough in the furrow Planting; unlike the sowing, planting of arable crops involves the putting of the vegetative parts of the crops which are propagated into the field Transplanting; a planting practice that includes the transplanting of already raised seedlings into the field Top 5 Tips for Advanced Sowing/ Planting in Arable Farming In aiming to reach full crop potential, it’s extremely important to manage crop production properly from its earliest stages. Here are the top 5 farming practices, all of which are important to consider before the sowing or planting of arable crops. 1. Selection of the appropriate crop variety as according to the climatic and environmental conditions 2. Choosing the earliest recommended date for sowing 3. Ensuring a well-prepared soil 4. Practicing soil analysis before sowing/ planting 5. Regulating water (irrigation or drainage) and nutrients (fertilization according to the demands of crop and soil pH) Following recommended practices enables a farmer to be one step ahead of all obstacles. Moreover, farmers wanting the best results consider every important detail before the sowing. CHARACTERISTICS OF ARABLE FARMING IN NIGERIA 1. SIZE OF FARMS: Farms are generally small in size, sometimes over 0.5-5 hectares the farmers are small holder farmers. 2. LABOUR: Uses a large labour force, hired labour, labour mainly seasonal (mainly during planting and harvesting time). 3. Crop Production is seasonal 4. PURPOSE: Mainly plant crop for local consumption 5. RELIEF OF LAND is undulating either there are valleys or hill that prevent for easy movement of machinery 6. LAND PREPARATION TECHNIQUE/TOOLS USED they normally use hoes and cutlasses hence the lad are to be cleared is usually small 7. There is little or lack of credit facilities 8. Chemicals such as fertilizer, herbicide, pesticides, fungicides. Uses machinery such as combine harvesters, crawlers, tractors, and ploughs to speed up planting and harvesting time. 9. METHOD OF FARMING Practices multiple cropping cultivation of several crops eg. Sugar cane, bananas. Agronomy (from Ancient Greek agrós "field" and nómos "law") is the science and technology of producing and using plants for food, fuel, fiber, and land reclamation. The management, utilization and marketing of crops in large area. It can also be defined as the branch of agriculture that deals with the principles and practices of soil management and crop production. Agronomy has come to encompass work in the areas of plant genetics, plant physiology, meteorology, and soil science. It is the application of a combination of sciences like biology, chemistry, economics, ecology, earth science, and genetics. Agronomists of today are involved with many issues, including producing food, creating healthier food, managing the environmental impact of agriculture, and extracting energy from plants. Agronomists often specialize in areas such as crop rotation, irrigation and drainage, plant breeding, plant classification, soil fertility, weed control, and insect and pest control. physiology, soil The Practice That Marks the Beginning of Arable Crop Life Cycle Arable farming is a type of crop production that produces a wide range of annual crops. This means that the crop life cycle, from germination to seed production, is complete within one year. Depending on the type of use, there are a few different types of arable crops. These include:       Grain crops; cultivated grasses and millets grown for their edible starch grains (wheat, maize, rice, barley, proso millet) Pulse crops; edible seeds from the legume family, high in protein (lentil, beans, peas) Oil seed crops; grown for the oil extraction from the seeds (rapeseed, soybean, sunflower) Forage crops; crops used for animal feed, fresh or preserved (cowpea, clovers, timothy) Fiber crops; crops grown for fiber yield (cotton, jute, flax) Tuber crops; crops whose edible portion is a short thickened underground stem (potato, elephant yam) Sowing or Planting of Arable Crops? Since arable farming encompasses a wide range of different crops, we have to consider the sowing, as well as planting. There is a big difference between these two farm practices. For instance, - sowing is a practice that involves putting seeds into the soils. - planting means putting an already live plant into the soil. The plant can be grown by a farmer or purchased from a nursery. An additional difference between sowing and planting is in the crop spacing and density. For instance, sowing row spacing is usually smaller than in planting. On the other hand, crop density is higher than in the crops that are sown. However, a common feature of both practices is that each practice can be done manually or with the use of machinery. Sowing and Planting Types in Arable Farming There are a few methods of sowing and planting in arable farming, including:    Broad casting; the sowing practice that scatters the seeds by hand all over the prepared field Drilling or line sowing; sowing of crops with the use of machinery Dibbling; sowing method of placing the seeds at cross marks made in the field; this practice is done manually using a dibbler    Putting seeds behind the plough; a practice that involves the dropping of seeds manually behind the plough in the furrow Planting; unlike the sowing, planting of arable crops involves the putting of the vegetative parts of the crops which are propagated into the field Transplanting; a planting practice that includes the transplanting of already raised seedlings into the field Top 5 Tips for Advanced Sowing/ Planting in Arable Farming In aiming to reach full crop potential, it’s extremely important to manage crop production properly from its earliest stages. Here are the top 5 farming practices, all of which are important to consider before the sowing or planting of arable crops. 1. Selection of the appropriate crop variety as according to the climatic and environmental conditions 2. Choosing the earliest recommended date for sowing 3. Ensuring a well-prepared soil 4. Practicing soil analysis before sowing/ planting 5. Regulating water (irrigation or drainage) and nutrients (fertilization according to the demands of crop and soil pH) Following recommended practices enables a farmer to be one step ahead of all obstacles. Moreover, farmers wanting the best results consider every important detail before the sowing. FACTORS AFFECTING CROP PRODUCTION Two major Factors: Genetic factors The increase in crop yields and other desirable characters are related to Genetic makeup of plants.  High yielding ability  Early maturity  Resistance to lodging  Drought flood and salinity tolerance  Tolerance to insect pests and diseases  Chemical composition of grains (oil content, protein content)  Quality of grains (fineness, coarseness)  Quality of straw (sweetness, juiciness) The above characters are less influenced by environmental factors since they are governed by genetic make-up of crop. External factors  Climatic  Edaphic  Biotic  Phsiographic  Socio-economic CLIMATIC FACTORS Nearly 50 % of yield is attributed to the influence of climatic factors. The following are the atmospheric weather variables or elements of weather which influences crop production.  Precipitation  Temperature  Atmospheric humidity  Solar radiation  Wind velocity  Atmospheric gases  Precipitation 1. Precipitation includes all water which falls from atmosphere such as rainfall, snow, hail, fog and dew. 2. Rainfall one of the most important factor influences the vegetation of a place. 3. Total precipitation in amount and distribution greatly affects the choice of a cultivated species in a place. 4. In heavy and evenly distributed rainfall areas, crops like rice in plains and tea, coffee and rubber in Western Ghats are grown. 5. Low and uneven distribution of rainfall is common in dryland farming where drought resistance crops like pearl millet, sorghum and minor millets are grown. 6. In desert areas grasses and shrubs are common where hot desert climate exists. 7. Though the rainfall has major influence on yield of crops, yields are not always directly proportional to the amount of Precipitation as excess above optimum reduces the yields. 8. Distribution of rainfall is more important than total rainfall to have longer growing period especially in drylands. Lecture 10/03/2020  Temperature Temperature is a measure of intensity of heat energy. The range of temperature for maximum growth of most of the agricultural plants is between 15 and 40ºC. The temperature of a place is largely determined by its distance from the equator (latitude) and altitude. 1. It influences distribution of crop plants and vegetation. 2. Germination, growth and development of crops are highly influenced by temperature. 3. Affects leaf production, expansion and flowering. 4. Physical and chemical processes within the plants are governed by air temperature. 5. Diffusion rates of gases and liquids changes with temperature. 6. Crops Minimum temperature ºC Optimum temperature ºC Maximum temperature ºC Rice 10 32 36-38 Wheat 4.5 20 30-32 Maize 8-10 20 40-43 Sorghum 12-13 25 40 Tobacco 12-14 29 35 Solubility of different substances in plant is dependent on temperature. 7. The minimum, maximum (above which crop growth ceases) and optimum temperature of individual’s plant is called as cardinal temperature. Atmospheric Humidity (Relative Humidity – RH) Water is present in the atmosphere in the form of invisible water vapour, normally known as humidity. Relative humidity is ratio between the amount of moisture present in the air to the saturation capacity of the air at a particular temperature. If relative humidity is 100% it means that the entire space is filled with water and there is no soil evaporation and plant transpiration. 1. Relative humidity influences the water requirement of crops 2. Relative humidity of 40-60% is suitable for most of the crop plants. 3. Very few crops can perform well when relative humidity is 80% and above. 4. When relative humidity is high there is chance for the outbreak of pest and disease. Solar radiation (without which life will not exist) From germination to harvest and even post-harvest crops are affected by solar radiation. Biomass production by photosynthetic processes requires light. All physical process taking place in the soil, plant and environment are dependent on light. Solar radiation controls distribution of temperature and there by distribution of crops in a region. Visible radiation is very important in photosynthetic mechanism of plants. Photo synthetically Active Radiation (PAR – 0.4 – 0.7μ) is essential for production of carbohydrates and ultimately biomass. 0.4 to 0.5 μ – Blue – violet – Active 0.5 to 0.6 μ – Orange – red – Active 0.5 to 0.6 μ – Green –yellow – low active Photoperiodism is a response of plant to day length Short day – Day length is 12 hours (Barley, oat, carrot and cabbage), day neutral – There is no or less influence on day length (Tomato and maize). Phototropism –– Response of plants to light direction. Eg. Sunflower Photosensitive – Season bound varieties depends on quantity of light received Wind velocity 1. The basic function of wind is to carry moisture (precipitation) and heat. 2. The moving wind not only supplies moisture and heat, also supplies fresh CO2 for the photosynthesis. 3. Wind movement for 4 – 6 km/hour is suitable for more crops. 4. When wind speed is enormous then there is mechanical damage of the crops (i.e.) it removes leaves and twigs and damages crops like banana, sugarcane 5. Wind dispersal of pollen and seeds is natural and necessary for certain crops. 6. Causes soil erosion. 7. Helps in cleaning produce to farmers. 8. Increases evaporation. 9. Spread of pest and diseases. Atmospheric gases on plant growth   CO2 – 0.03%, O2 – 20.95%, N2 – 78.09%, Argon – 0.93%, Others – 0.02%. CO2 is important for Photosynthesis, CO2 taken by the plants by diffusion process from leaves through stomata  CO2 is returned to atmosphere during decomposition of organic materials, all farm wastes and by respiration  O2 is important for respiration of both plants and animals while it is released by plants during Photosynthesis  Nitrogen is one of the important major plant nutrient, Atmospheric N is fixed in the soil by lightning, rainfall and N fixing microbes in pulses crops and available to plants  Certain gases like SO2, CO, CH4, HF released to atmosphere are toxic to plants READ Buckwheat Benefits Nature EDAPHIC FACTORS (soil) Plants grown in land completely depend on soil on which they grow. The soil factors that affect crop growth are  Soil moisture  Soil air  Soil temperature  Soil mineral matter  Soil organic matter  Soil organisms  Soil reactions Soil moisture  Water is a principal constituent of growing plant which it extracts from soil  Water is essential for photosynthesis  The moisture range between field capacity and permanent wilting point is available to plants.   Available moisture will be more in clay soil than sandy soil Soil water helps in chemical and biological activities of soil including mineralization  It influences the soil environment Eg. it moderates the soil temperature from extremes  Nutrient availability and mobility increases with increase in soil moisture content. Soil air  Aeration of soil is absolutely essential for the absorption of water by roots  Germination is inhibited in the absence of oxygen  O2 is required for respiration of roots and microorganisms.  Soil air is essential for nutrient availability of the soil by breaking down insoluble mineral to soluble salts  For proper decomposition of organic matter  Potato, tobacco, cotton linseed, tea and legumes need higher O2 in soil air  Rice requires low level of O2 and can tolerate water logged (absence of O2) condition. Soil temperature  It affects the physical and chemical processes going on in the soil.  It influences the rate of absorption of water and solutes (nutrients)  It affects the germination of seeds and growth rate of underground portions of the crops like sweet potato.  Soil temperature controls the microbial activity and processes involved in the nutrient availability  Cold soils are not conducive for rapid growth of most of agricultural crops Soil mineral matter  The mineral content of soil is derived from the weathering of rocks and minerals as particles of different sizes.  These are the sources of plant nutrients eg; Ca, Mg, S, Mn, Fe, K etc Soil Organic matter  It supplies all the major, minor and micro nutrients to crops  It improves the texture of the soil  It increases the water holding capacity of the soil.  It is a source of food for most microorganisms  Organic acids released during decomposition of organic matter enables mineralisation process thus releasing unavailable plant nutrients Soil organisms  The raw organic matter in the soil is decomposed by different microorganisms which in turn releases the plant nutrients  Atmospheric nitrogen is fixed by microbes in the soil and is available to crop plants through symbiotic (Rhizobium) or non-symbiotic (Azospirillum) association Soil reaction (pH)   Soil reaction is the pH (hydrogen ion concentration) of the soil. Soil pH affects crop growth and neutral soils with pH 7.0 are best for growth of most of the crops  Soils may be acidic (7.0)  Soils with low pH is injurious to plants due high toxicity of Fe and Al.  Low pH also interferes with availability of other plant nutrients. BIOTIC FACTORS Beneficial and harmful effects caused by other biological organism (plants and animals) on the crop plants Plants   Competitive and complementary nature among field crops when grown together Competition between plants occurs when there is demand for nutrients, moisture and sunlight particularly when they are in short supply or when plants are closely spaced  When different crops of cereals and legumes are grown together, mutual benefit results in higher yield (synergistic effect)  Competition between weed and crop plants as parasites eg: Striga parasite weed on sugarcane crop Animals  Soil fauna like protozoa, nematode, snails, and insects help in organic matter decomposition, while using organic matter for their living  Insects and nematodes cause damage to crop yield and considered as harmful organisms.  Honey bees and wasps help in cross pollination and increases yield and considered as beneficial organisms  Burrowing earthworm facilitates aeration and drainage of the soil as ingestion of organic and mineral matter by earthworm results in constant mixing of these materials in the soils.  Large animals cause damage to crop plants by grazing (cattle, goats etc) Physiographic factors:  Topography is the nature of surface earth (leveled or sloppy) is known as topography. Topographic factors affect the crop growth indirectly.  Altitude – increase in altitude cause a decrease in temperature and increase in precipitation and wind velocity (hills and plains)  Steepness of slope: it results in run off of rain water and loss of nutrient rich top soil  Exposure to light and wind: a mountain slope exposed to low intensity of light and strong dry winds may results in poor crop yields (coastal areas and interior pockets) Socio-economic factors   Society inclination to farming and members available for cultivation Appropriate choice of crops by human beings to satisfy the food and fodder requirement of farm household.  Breeding varieties by human invention for increased yield or pest & disease resistance The economic condition of the farmers greatly decides the input/ resource mobilizing ability (marginal, small, medium and large farmers) Other factors include Loss of cropland Cropland has been lost because of various reasons, the most noteworthy of them being as follows:  Rapid urban development and accompanying development of infrastructure has been primarily at the cost of agricultural land. As settlements, towns and cities grow; adjacent cropland is reduced to accommodate roads, industries and buildings. With expected increase in world urban population from about 3 billion people in 2000 to 5 billion in 2030 (according to UN projections), built-up area is likely to increase to about 0.7 per cent by 2030. This is likely to be at the expense of cropland.  Cropland area has been lost to degradation because of deforestation and inappropriate agricultural practices. It is estimated by several researchers that globally, 20,000-50,000 sq. km. of land are lost annually, mainly because of soil erosion, the losses being some 3-6 times higher in Africa, Latin America and Asia than in North America and Europe. The major areas of degradation are in Africa, south of the equator, South-East Asia, Southern China, North-Central Australia, and the pampas of South America. More than 900,000 sq km of land in sub-Saharan Africa is threatened with irreversible degradation if nutrient depletion is allowed to continue. In most parts of Asia, forest is shrinking, agriculture is gradually expanding to marginal land, and nutrient leaching and soil erosion are accelerating land degradation.  Changes in the proportion of non-food crops to food crops could have a significant impact on available cropland for food production. Biofuels (which include biodiesel from palm oil and ethanol from sugarcane, corn and soya-bean) have become prominent given the circumstances of high oil prices and the initial perception that they are environmentally friendly in reducing carbon dioxide emissions. North America and Europe have set high targets to convert to biofuels. Many countries, such as Indonesia and Malaysia, see’ in biofuels an opportunity to improve rural livelihoods and boost the economy through exports. Though biofuels are a potential low-carbon energy source, the conversion of rainforests, peatlands, and savannas to produce biofuels in the US, Brazil and South East Asia may actually release more carbon dioxide than the reductions in greenhouse gases brought about by using biofuels as an energy source. The main potential of biofuels lies in using biomass grown in wastelands or abandoned agricultural land. It has also been pointed out that growing crops for biofuels competes with food production; according to some calculations, the corn equivalent of a full tank of ethanol in a 4-wheel drive suburban utility vehicle (SUV) could practically feed one person for a year. As a consequence of diverting cropland to biofuel production, food prices are expected to rise drastically. Production of other non-food crops, such as cotton, is also projected to increase. Again, this would be at the expense of food production. Reduced yields Due to environmental degradation and loss of ecosystem components, there would be reduced yield of food crops. Unsustainable practices in irrigation and production may lead to increased salinisation of soil, depletion of soil nutrients, and erosion. This, in turn, will cause lower yields. The productivity of some lands has declined by 50 per cent due to soil erosion and desertification. Africa is considered to be the continent most severely affected by land degradation. Global climate change can also affect food production: by changing overall growing conditions (rainfall distribution, temperature regime); by inducing more extreme weather such as floods, storms, and drought; and by increasing extent, type and frequency of infestations, including that of invasive alien species. All this would be bound to adversely affect yield. An important factor in agricultural, yield is water: agriculture accounts for nearly 70 per cent of water consumption. Water scarcity is expected to affect over 1.8 billion people by 2025 according to the World Health Organisation. This could cause not only health problems but also impact farm productivity. Watersheds have been damaged. The global consumption of both ‘blue’ water (withdrawn for irrigation from lakes, rivers and aquifers) and ‘green’ water (precipitation) by rain-fed and irrigated agriculture and other terrestrial ecosystems is steadily increasing. Water may be considered as one of the most limiting factors in increasing food production. Over- extraction of water resources from aquifers and rivers has led to much loss of this resource. River discharge has decreased in many areas mainly as a result of human action and use. This water scarcity is likely to reduce yields of food grains, as 40 per cent of world’s crop yields is based on irrigation. Invasive Alien Species Invasive alien species—pests and diseases—are another threat to food production. Pests and pathogens have had particularly severe effects on crop yields in the world’s poorest and most food insecure region of sub-Saharan Africa. Increased climate extremes may encourage the spread of plant diseases, pest outbreaks and weeds. The spread of invasive alien species also occurs in the provisions of humanitarian food aid in times of famine and disaster emergencies, as lower sanitary and phytosanitary standards apply to such food aid. The Practice That Marks the Beginning of Arable Crop Life Cycle Arable farming is a type of crop production that produces a wide range of annual crops. This means that the crop life cycle, from germination to seed production, is complete within one year. Depending on the type of use, there are a few different types of arable crops. These include:       Grain crops; cultivated grasses and millets grown for their edible starch grains (wheat, maize, rice, barley, proso millet) Pulse crops; edible seeds from the legume family, high in protein (lentil, beans, peas) Oil seed crops; grown for the oil extraction from the seeds (rapeseed, soybean, sunflower) Forage crops; crops used for animal feed, fresh or preserved (cowpea, clovers, timothy) Fiber crops; crops grown for fiber yield (cotton, jute, flax) Tuber crops; crops whose edible portion is a short thickened underground stem (potato, elephant yam) Sowing or Planting of Arable Crops? Since arable farming encompasses a wide range of different crops, we have to consider the sowing, as well as planting. There is a big difference between these two farm practices. For instance, sowing is a practice that involves putting seeds into the soils. While, planting means putting an already live plant into the soil. The plant can be grown by a farmer or purchased from a nursery. An additional difference between sowing and planting is in the crop spacing and density. For instance, sowing row spacing is usually smaller than in planting. On the other hand, crop density is higher than in the crops that are sown. However, a common feature of both practices is that each practice can be done manually or with the use of machinery. Sowing and Planting Types in Arable Farming There are a few methods of sowing and planting in arable farming, including:    Broad casting; the sowing practice that scatters the seeds by hand all over the prepared field Drilling or line sowing; sowing of crops with the use of machinery Dibbling; sowing method of placing the seeds at cross marks made in the field; this practice is done manually using a dibbler    Putting seeds behind the plough; a practice that involves the dropping of seeds manually behind the plough in the furrow Planting; unlike the sowing, planting of arable crops involves the putting of the vegetative parts of the crops which are propagated into the field Transplanting; a planting practice that includes the transplanting of already raised seedlings into the field Top 5 Tips for Advanced Sowing/ Planting in Arable Farming In aiming to reach full crop potential, it’s extremely important to manage crop production properly from its earliest stages. Here are the top 5 farming practices, all of which are important to consider before the sowing or planting of arable crops. 1. Selection of the appropriate crop variety as according to the climatic and environmental conditions 2. Choosing the earliest recommended date for sowing 3. Ensuring a well-prepared soil 4. Practicing soil analysis before sowing/ planting 5. Regulating water (irrigation or drainage) and nutrients (fertilization according to the demands of crop and soil pH) Following recommended practices enables a farmer to be one step ahead of all obstacles. Moreover, farmers wanting the best results consider every important detail before the sowing. FACTORS AFFECTING CROP PRODUCTION Two major Factors: Genetic factors The increase in crop yields and other desirable characters are related to Genetic makeup of plants.  High yielding ability  Early maturity  Resistance to lodging  Drought flood and salinity tolerance  Tolerance to insect pests and diseases  Chemical composition of grains (oil content, protein content)  Quality of grains (fineness, coarseness)  Quality of straw (sweetness, juiciness) The above characters are less influenced by environmental factors since they are governed by genetic make-up of crop. External factors  Climatic  Edaphic  Biotic  Phsiographic  Socio-economic CLIMATIC FACTORS Nearly 50 % of yield is attributed to the influence of climatic factors. The following are the atmospheric weather variables or elements of weather which influences crop production.  Precipitation  Temperature  Atmospheric humidity  Solar radiation  Wind velocity  Atmospheric gases  Precipitation 1. Precipitation includes all water which falls from atmosphere such as rainfall, snow, hail, fog and dew. 2. Rainfall one of the most important factor influences the vegetation of a place. 3. Total precipitation in amount and distribution greatly affects the choice of a cultivated species in a place. 4. In heavy and evenly distributed rainfall areas, crops like rice in plains and tea, coffee and rubber in Western Ghats are grown. 5. Low and uneven distribution of rainfall is common in dryland farming where drought resistance crops like pearl millet, sorghum and minor millets are grown. 6. In desert areas grasses and shrubs are common where hot desert climate exists. 7. Though the rainfall has major influence on yield of crops, yields are not always directly proportional to the amount of Precipitation as excess above optimum reduces the yields. 8. Distribution of rainfall is more important than total rainfall to have longer growing period especially in drylands. Temperature Temperature is a measure of intensity of heat energy. The range of temperature for maximum growth of most of the agricultural plants is between 15 and 40ºC. The temperature of a place is largely determined by its distance from the equator (latitude) and altitude. 1. It influences distribution of crop plants and vegetation. 2. Germination, growth and development of crops are highly influenced by temperature. 3. Affects leaf production, expansion and flowering. 4. Physical and chemical processes within the plants are governed by air temperature. 5. Diffusion rates of gases and liquids changes with temperature. Crops Minimum temperature ºC Optimum temperature ºC Maximum temperature ºC Rice 10 32 36-38 Wheat 4.5 20 30-32 Maize 8-10 20 40-43 Sorghum 12-13 25 40 Tobacco 12-14 29 35 6. Solubility of different substances in plant is dependent on temperature. 7. The minimum, maximum (above which crop growth ceases) and optimum temperature of individual’s plant is called as cardinal temperature. Atmospheric Humidity (Relative Humidity – RH) Water is present in the atmosphere in the form of invisible water vapour, normally known as humidity. Relative humidity is ratio between the amount of moisture present in the air to the saturation capacity of the air at a particular temperature. If relative humidity is 100% it means that the entire space is filled with water and there is no soil evaporation and plant transpiration. 1. Relative humidity influences the water requirement of crops 2. Relative humidity of 40-60% is suitable for most of the crop plants. 3. Very few crops can perform well when relative humidity is 80% and above. 4. When relative humidity is high there is chance for the outbreak of pest and disease. Solar radiation (without which life will not exist) From germination to harvest and even post-harvest crops are affected by solar radiation. Biomass production by photosynthetic processes requires light. All physical process taking place in the soil, plant and environment are dependent on light. Solar radiation controls distribution of temperature and there by distribution of crops in a region. Visible radiation is very important in photosynthetic mechanism of plants. Photo synthetically Active Radiation (PAR – 0.4 – 0.7μ) is essential for production of carbohydrates and ultimately biomass. 0.4 to 0.5 μ – Blue – violet – Active 0.5 to 0.6 μ – Orange – red – Active 0.5 to 0.6 μ – Green –yellow – low active Photoperiodism is a response of plant to day length Short day – Day length is 12 hours (Barley, oat, carrot and cabbage), day neutral – There is no or less influence on day length (Tomato and maize). Phototropism –– Response of plants to light direction. Eg. Sunflower Photosensitive – Season bound varieties depends on quantity of light received Wind velocity 1. The basic function of wind is to carry moisture (precipitation) and heat. 2. The moving wind not only supplies moisture and heat, also supplies fresh CO 2 for the photosynthesis. 3. Wind movement for 4 – 6 km/hour is suitable for more crops. 4. When wind speed is enormous then there is mechanical damage of the crops (i.e.) it removes leaves and twigs and damages crops like banana, sugarcane 5. Wind dispersal of pollen and seeds is natural and necessary for certain crops. 6. Causes soil erosion. 7. Helps in cleaning produce to farmers. 8. Increases evaporation. 9. Spread of pest and diseases. Atmospheric gases on plant growth  CO2 – 0.03%, O2 – 20.95%, N2 – 78.09%, Argon – 0.93%, Others – 0.02%.  CO2 is important for Photosynthesis, CO2 taken by the plants by diffusion process from leaves through stomata  CO2 is returned to atmosphere during decomposition of organic materials, all farm wastes and by respiration  O2 is important for respiration of both plants and animals while it is released by plants during Photosynthesis  Nitrogen is one of the important major plant nutrient, Atmospheric N is fixed in the soil by lightning, rainfall and N fixing microbes in pulses crops and available to plants  Certain gases like SO2, CO, CH4, HF released to atmosphere are toxic to plants READ Buckwheat Benefits Nature EDAPHIC FACTORS (soil) Plants grown in land completely depend on soil on which they grow. The soil factors that affect crop growth are  Soil moisture  Soil air  Soil temperature  Soil mineral matter  Soil organic matter  Soil organisms  Soil reactions Soil moisture  Water is a principal constituent of growing plant which it extracts from soil  Water is essential for photosynthesis  The moisture range between field capacity and permanent wilting point is available to plants.  Available moisture will be more in clay soil than sandy soil  Soil water helps in chemical and biological activities of soil including mineralization  It influences the soil environment Eg. it moderates the soil temperature from extremes  Nutrient availability and mobility increases with increase in soil moisture content. Soil air  Aeration of soil is absolutely essential for the absorption of water by roots  Germination is inhibited in the absence of oxygen  O2 is required for respiration of roots and microorganisms.  Soil air is essential for nutrient availability of the soil by breaking down insoluble mineral to soluble salts  For proper decomposition of organic matter  Potato, tobacco, cotton linseed, tea and legumes need higher O 2 in soil air  Rice requires low level of O2 and can tolerate water logged (absence of O2) condition. Soil temperature  It affects the physical and chemical processes going on in the soil.  It influences the rate of absorption of water and solutes (nutrients)  It affects the germination of seeds and growth rate of underground portions of the crops like sweet potato.  Soil temperature controls the microbial activity and processes involved in the nutrient availability  Cold soils are not conducive for rapid growth of most of agricultural crops Soil mineral matter  The mineral content of soil is derived from the weathering of rocks and minerals as particles of different sizes.  These are the sources of plant nutrients eg; Ca, Mg, S, Mn, Fe, K etc Soil Organic matter  It supplies all the major, minor and micro nutrients to crops  It improves the texture of the soil  It increases the water holding capacity of the soil.  It is a source of food for most microorganisms  Organic acids released during decomposition of organic matter enables mineralisation process thus releasing unavailable plant nutrients Soil organisms  The raw organic matter in the soil is decomposed by different microorganisms which in turn releases the plant nutrients  Atmospheric nitrogen is fixed by microbes in the soil and is available to crop plants through symbiotic (Rhizobium) or non-symbiotic (Azospirillum) association Soil reaction (pH)  Soil reaction is the pH (hydrogen ion concentration) of the soil.  Soil pH affects crop growth and neutral soils with pH 7.0 are best for growth of most of the crops  Soils may be acidic (7.0)  Soils with low pH is injurious to plants due high toxicity of Fe and Al.  Low pH also interferes with availability of other plant nutrients. BIOTIC FACTORS Beneficial and harmful effects caused by other biological organism (plants and animals) on the crop plants Plants  Competitive and complementary nature among field crops when grown together  Competition between plants occurs when there is demand for nutrients, moisture and sunlight particularly when they are in short supply or when plants are closely spaced  When different crops of cereals and legumes are grown together, mutual benefit results in higher yield (synergistic effect)  Competition between weed and crop plants as parasites eg: Striga parasite weed on sugarcane crop Animals  Soil fauna like protozoa, nematode, snails, and insects help in organic matter decomposition, while using organic matter for their living  Insects and nematodes cause damage to crop yield and considered as harmful organisms.  Honey bees and wasps help in cross pollination and increases yield and considered as beneficial organisms  Burrowing earthworm facilitates aeration and drainage of the soil as ingestion of organic and mineral matter by earthworm results in constant mixing of these materials in the soils.  Large animals cause damage to crop plants by grazing (cattle, goats etc) Physiographic factors:  Topography is the nature of surface earth (leveled or sloppy) is known as topography. Topographic factors affect the crop growth indirectly.  Altitude – increase in altitude cause a decrease in temperature and increase in precipitation and wind velocity (hills and plains)  Steepness of slope: it results in run off of rain water and loss of nutrient rich top soil  Exposure to light and wind: a mountain slope exposed to low intensity of light and strong dry winds may results in poor crop yields (coastal areas and interior pockets) Socio-economic factors  Society inclination to farming and members available for cultivation  Appropriate choice of crops by human beings to satisfy the food and fodder requirement of farm household.  Breeding varieties by human invention for increased yield or pest & disease resistance The economic condition of the farmers greatly decides the input/ resource mobilizing ability (marginal, small, medium and large farmers) Other factors include Loss of cropland Cropland has been lost because of various reasons, the most noteworthy of them being as follows:  Rapid urban development and accompanying development of infrastructure has been primarily at the cost of agricultural land. As settlements, towns and cities grow; adjacent cropland is reduced to accommodate roads, industries and buildings. With expected increase in world urban population from about 3 billion people in 2000 to 5 billion in 2030 (according to UN projections), built-up area is likely to increase to about 0.7 per cent by 2030. This is likely to be at the expense of cropland.  Cropland area has been lost to degradation because of deforestation and inappropriate agricultural practices. It is estimated by several researchers that globally, 20,000-50,000 sq. km. of land are lost annually, mainly because of soil erosion, the losses being some 3-6 times higher in Africa, Latin America and Asia than in North America and Europe. The major areas of degradation are in Africa, south of the equator, South-East Asia, Southern China, North-Central Australia, and the pampas of South America. More than 900,000 sq km of land in sub-Saharan Africa is threatened with irreversible degradation if nutrient depletion is allowed to continue. In most parts of Asia, forest is shrinking, agriculture is gradually expanding to marginal land, and nutrient leaching and soil erosion are accelerating land degradation.  Changes in the proportion of non-food crops to food crops could have a significant impact on available cropland for food production. Biofuels (which include biodiesel from palm oil and ethanol from sugarcane, corn and soya-bean) have become prominent given the circumstances of high oil prices and the initial perception that they are environmentally friendly in reducing carbon dioxide emissions. North America and Europe have set high targets to convert to biofuels. Many countries, such as Indonesia and Malaysia, see’ in biofuels an opportunity to improve rural livelihoods and boost the economy through exports. Though biofuels are a potential low-carbon energy source, the conversion of rainforests, peatlands, and savannas to produce biofuels in the US, Brazil and South East Asia may actually release more carbon dioxide than the reductions in greenhouse gases brought about by using biofuels as an energy source. The main potential of biofuels lies in using biomass grown in wastelands or abandoned agricultural land. It has also been pointed out that growing crops for biofuels competes with food production; according to some calculations, the corn equivalent of a full tank of ethanol in a 4-wheel drive suburban utility vehicle (SUV) could practically feed one person for a year. As a consequence of diverting cropland to biofuel production, food prices are expected to rise drastically. Production of other non-food crops, such as cotton, is also projected to increase. Again, this would be at the expense of food production. Reduced yields Due to environmental degradation and loss of ecosystem components, there would be reduced yield of food crops. Unsustainable practices in irrigation and production may lead to increased salinisation of soil, depletion of soil nutrients, and erosion. This, in turn, will cause lower yields. The productivity of some lands has declined by 50 per cent due to soil erosion and desertification. Africa is considered to be the continent most severely affected by land degradation. Global climate change can also affect food production: by changing overall growing conditions (rainfall distribution, temperature regime); by inducing more extreme weather such as floods, storms, and drought; and by increasing extent, type and frequency of infestations, including that of invasive alien species. All this would be bound to adversely affect yield. An important factor in agricultural, yield is water: agriculture accounts for nearly 70 per cent of water consumption. Water scarcity is expected to affect over 1.8 billion people by 2025 according to the World Health Organisation. This could cause not only health problems but also impact farm productivity. Watersheds have been damaged. The global consumption of both ‘blue’ water (withdrawn for irrigation from lakes, rivers and aquifers) and ‘green’ water (precipitation) by rain-fed and irrigated agriculture and other terrestrial ecosystems is steadily increasing. Water may be considered as one of the most limiting factors in increasing food production. Over- extraction of water resources from aquifers and rivers has led to much loss of this resource. River discharge has decreased in many areas mainly as a result of human action and use. This water scarcity is likely to reduce yields of food grains, as 40 per cent of world’s crop yields is based on irrigation. Invasive Alien Species Invasive alien species—pests and diseases—are another threat to food production. Pests and pathogens have had particularly severe effects on crop yields in the world’s poorest and most food insecure region of sub-Saharan Africa. Increased climate extremes may encourage the spread of plant diseases, pest outbreaks and weeds. The spread of invasive alien species also occurs in the provisions of humanitarian food aid in times of famine and disaster emergencies, as lower sanitary and phytosanitary standards apply to such food aid. (CROP ESTABLISHMENT) SOWING AND PLANTING OF CROP Seeds are first covered with earth from open furrows, then the crops are mulched with decayed manure and peat soil. The depth of seed sowing depends not only on their size, but also on the type and texture of the soil: if the soil is heavy, wet, the seeds are sown finely, and if the dry soil is deeper. Seed Germination: Seed germination is a process where a seed or spore develops and grows into new plants. The growth of an embryo from seed into seedling under favourable conditions is called seed germination. Seed germination can also be defined as a process in which different plant species grow from a single seed into a plant. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ferns, bacteria, and the growth of the pollen tube from the pollen grain of a seed plant. Seeds and Methods of sowing (power points) Factors affecting seed germination   External or environmental factors Internal factors External or environmental factors: The seeds of all species essentially require at least three external conditions for germination. These four factors are –     Water Suitable temperature Oxygen Light Water: The supply of water is one of the essential requirements in the germination of seeds. Water is necessary for the physical and chemical processes that take place in the germinating seeds. With the imbibition of water, the seed coat becomes soft and permeable to water. In their resulting state, seeds are characterized as low in moisture and relatively metabolically inactive. Water is also necessary for each germination stage, starting from imbibition, activating the enzyme, digestion of soluble complex food to soluble forms, and translocation to the assimilation into living protoplasm. The amount and rate of water absorption depend upon the kinds of seed during germination and storage. The rate of water absorption increases with the increase of temperature. Soaking and steeping of seeds before planting are sometimes practices to enhance germination. This practice is advantageous for seeds with hard or dry seed coats or with a dormant embryo. Excess water is harmful for seed germination as most of the seed can not respire under poor aeration conditions in a germination medium. Often, oversupply of water favors the damping off. 2. Suitable temperature: Temperature affects the absorption of water. The intake of oxygen and chemical reaction in germinating seeds. The temperature requirement for the seed germination is generally considered about threepoint/There are 3 stages of temperature – minimum, maximum, and optimum. Minimum or maximum temperature below or above the seed germination does not occur. The largest number of seeds and particular species germinate at 26.5 – 36°C may be said as optimum temperature. The non – dormant seed of small grains, clover, radish, onion, etc., germinate at very close to 20°C. Spinach seeds germinate at 10°C or very close to 20°C. Freshly harvested seeds of cucumber and watermelon germinate at a high temperature of 30°C. Wheat seeds (slightly above 35°C) and maize seeds (5 – 45°C) germinate at a wide range of temperatures. Commonly used practices are 15°C or 20°C for 16 – 18 hours and 30°C for 6 – 8 hours. The effect of alternating temperature on germination is called thermoperiodism. 3. Oxygen Oxygen is an essential requirement in respiration which supplies energy to remain life by oxidation of foods. During germination, the oxidation rate increases. C6H12O6 + 6O6= 6CO2 + 6H2O + 673 kCal energy Oxygen uptake is increased, and Carbon dioxide is given off at an increased rate. Oxygen is responsible in some way regarding the initial reaction of germination. Reduced aeration decrease the germination rate seeds of water plant and rice seed can usually germinate underwater. The ability of rice seed to germinate at low oxygen presence due to the presence of an anaerobic condition energy liberating system within the seeds. 4. Light: Visible light can stimulate or inhibit the germination of some plant species. Epiphytic plants have an essential requirement for light. While light inhibits the germination of some plant species, i.e., Allium amaranthus, etc. Light also favors the germination of lettuce, tobacco, and cauliflower. Germination is controlled by a reversible photochemical reaction that involves a pigment’s response (Phytochrome) to the light of a specific wavelength. in red light Phytochrome Phytochrome (far red) (Inhibits germination) (Promotes germination) Imbibe seeds, when exposed to red light (wavelength 6400 – 6700 Å), the phytochrome (red) instantly changes to phytochrome (far red), which is associated in some way with inducing germination. Internal factors: The following internal factor plays a vital role for successful germination in the seed.     Presence of auxin. Reserved food Completion of dormancy Viability of seed 1. Presence of auxin: During germination, a chemical called auxin develops in the seeds, which stimulates germination. In addition, to increase, another substance known as heteroauxin develops in some seeds. Both auxin and heteroauxin are called growth regulators. 2. Presence of reserved food: Foods are stored in the endosperm (monocot seed) or cotyledons (dicot seed). The embryo is dependent on the reserved food. Germination is possible if the seed can provide with necessary food to the embryo. 3. Completion of dormancy: Inhibit the growth of seed due to some internal causes even through the environmental condition available for germination is called dormancy. So during the dormant period of seed, complete breaking of dormancy must be essential. 4. Seed viability: Viability refers to the seeds whether a seed is alive, dormant, or dead. If the seed is not viable, it will not germinate. Seed dormancy, Importance and overcoming seed dormancy 1. CONTENTS:- What is dormancy? Importance of seed dormancy Overcoming seed 2. 3. 4. 5. 6. 7. 8. dormancy a) Natural b)Treatments References 1. What is dormancy? The seed in many species (pisum, Oryza sativa etc.) would germinate. Immediately after falling from the plant if favorable conditions of moisture, temperature and aeration are available. There are some plants whose seeds fail to germinate, for some time after falling from parent plant. This period called dormancy period. Dormancy can be regulated by the environment or by the seed itself. In actual, dormancy can be define as a state in which seeds are prevented from germinating even under favorable environmental condition. 2. Importance of Seed Dormancy:- 1. Storage:- Storage of seeds is prolonged, it is a survival mechanism because of dormancy that human beings and other organisms are able to store grains, pulses and other edibles for making them available throughout the year and transport to the areas of deficiency. 2. Perennation:- Seed dormancy allows seeds to pass through adverse situation/conditions and it restrict germination in adverse sowing conditions such as heavy frost, dry weather or excessive moisture. 3. Maintain seed quality:- Impermeable seed-coat dormancy maintain seed quality under adverse conditions of harvest and storage, eg. Cotton. Dormancy Prevents the In-situ germination and helps in maintaining seed quality. i.e., vivipary. 4. Seed dispersal and Germination:- Seed dormancy essential for the seed dispersal and seed germination on suitable substratum. Seeds germinate only when favorable conditions (moisture, temperature and aeration) are available to leach out inhibitors and soften the seed coats. 4. Overcoming seed dormancy:- Natural Overcoming of Seed Dormancy:- The natural breaking of seed dormancy can when the embryo gets appropriate environment such as adaptive moisture, oxygen and temperature. The hard and impermeable seed coat that exists in many species that becomes permeable due to the rupturing of smoothing action of natural agents like microorganism, temperature and abrasion by the digestive tract enzymes of birds and animals that feed on these seeds. Some other natural methods include:- Leaching of inhibitors present in the seed coat. Inactivation or oxidation of inhibitors by heat, cold and light. Completion of over-ripening period. Attainment of maturity of embryo in case the dormancy is due to incomplete development of embryo. 5. Artificial / Tretments to Seed Dormancy:- 1. Scarification:- Any treatments may be physical or chemical that weakens or softens the seed coat is known as scarification. This method is more applicable to Malvaceae and Leguminaceae group of seeds. a) Mechanical scarification Seeds are rubbed on a sand paper or with a help of mechanical scarifier or by puncturing on seed coat with the help of needle to enhance / increase the moisture absorption by seeds. E.g. Bitter gourd for sand scarification, sand and seed 2:1 ratio should be followed. Rub against hard surface of seed for 5 to 10 minutes. b) Acid scarification By using concentrated H2SO4 in 100 ml/kg of seed for 2-3 minutes treatments dormancy can be overcome in the above group of seeds. The duration of treatment will vary and it depends on type and nature of seed coat. E.g. Tree crops 1-3 hours, Rose seeds, treat the seed partially with acid and then given with warm stratification. 2. Hot water treatments :- It is effective in case of leguminous tree crop seeds. The seeds should be soaked in boiled water for 1-5 minutes for 60-80 minutes. Some crops like Bengal gram and Groundnut, hot water treatment for more than 1 minute is found injurious to seed. 6.. Stratification treatment:- When seed dormancy is due to embryo factor, seeds can be subjected to stratification treatments. a) Cold stratification Incubate the seed at low temperature of 0-5 degree Celsius over a moist substratum for 2-3 days to several months. It depends on the nature of seed and kind of dormancy. (e.g.) Cherry and oil palm seeds. b) Warm stratification Some seeds require temperature of 40-50 0 C for few days e.g. paddy. In case of oil palm it requires temperature of40-50 0 C for 2 months for breaking dormancy. Care should be taken during the treatment and moisture content of seed should not be more than 15%. 4. Leaching of metabolites (Inhibitors):- The seeds can be soaked in water for 3 days. But once in 12 hours fresh water should be changed to avoid fermentation or seeds can be soaked in running water for a day to leach out the inhibitors. (e.g.) Coriander (Coumarin), Sunflower (Hydrocyanic acid) 9. 7. Temperature treatments:- a) Low temperature treatments Plants which grow in temperate and cooler climates, require a period of chilling for breakage of dormancy. E.g. Apple seed dormancy can be released by low temperature treatment by storing the seeds at 5 degree celsius. b) High temperature treatment Normally high temperature treatments are exhibited by early flowering "winter " annuals. E.g. Blue bell (Hyacinthoides nonscripta). c) Alternate temperature treatments Most of the plant species which grow in temperate and cool temperate regions require alternate temperature for breakage of dormancy (e.g.) Bull rush (Typha). d) Fire treatment Many shrubs and trees of sub tropical and semi-arid regions have extremely hard seeds in which the seed coat is very impervious to water. Dormancy in such seeds is clearly coat imposed, and may be broken by exposure to extreme heat such as fire. E.g. Seeds of Calluna vulgaris dormancy is broken by fire. 10. 8. Seed Treatment with Growth Regulators/Chemicals:- If the endogenous dormancy is due to the presence of inhibitors, we can apply growth regulators at the low level to break dormancy. GA & Cytokinin and kinetin can be used at concentration of 100-1000 ppm to break dormancy. GA is light substituting chemical. KNO3 2% can be used for breaking the dormancy of light requiring seeds (e.g.) Oats, Barley and Tomato. Thiourea can be used for breaking dormancy for both light and chilling treatment requiring seeds (e.g.) lettuce - thiourea @ 10-2 to 10-3 M is used. Ethrel can be used for breaking the dormancy of cotton seed. The dormancy in cotton seed is due to the presence of ABA in pericarp of seed. Nitrogenous compounds like Thiourea, Hydroxylamine, Nitric acid, Nitrtate, can also be used for breaking dormancy. Sulphidral compounds like 2 mercapto ethanol and 2,3 dimercapto ehtanol can also be used. Tillage tillage, in agriculture, the preparation of soil for planting and the cultivation of soil after planting. Tillage is the manipulation of the soil into a desired condition by mechanical means; tools are employed to achieve some desired effect (such as pulverization, cutting, or movement). Soil is tilled to change its structure, to kill weeds, and to manage crop residues. Soil structure modification is often necessary to facilitate the intake, storage, and transmission of water and to provide a good environment for seeds and roots. Elimination of weeds is important, because they compete for water, nutrients, and light. Crop residues on the surface must be managed in order to provide conditions suitable for seeding and cultivating a crop. See also no-till agriculture. Generally speaking, if the size of the soil aggregates or particles is satisfactory, preparation of the seedbed will consist only of removing weeds and the management of residues. Unfortunately, the practices associated with planting, cultivating, and harvesting usually cause destruction of soil structure. This leaves preparation of the seedbed as the best opportunity to create desirable structure, in which large and stable pores extend from the soil surface to the water table or drains, ensuring rapid infiltration and drainage of excess or free water and promoting aeration of the subsoil. When these large pores are interspersed with small ones, the soil will retain and store moisture also. Seedbed preparation procedures depend on soil texture and the desired change in size of aggregates. In soils of coarse texture, tillage will increase aggregate size, provided it is done when only the small pores are just filled with water; tillage at other than this ideal moisture will make for smaller aggregates. By contrast, finetextured soils form clods; these require breakage into smaller units by weathering or by machines. If too wet or too dry, the power requirements for shattering dry clods or cutting wet ones are prohibitive when using tillage alone. Thus, the farmer usually attempts tillage of such soils only after a slow rain has moistened the clods and made them friable. Some soils require deepening of the root zone to permit increased rate of water intake and improved storage. Unfavourable aeration in zones of poor drainage also limits root development and inhibits use of water in the subsoil. Tillage, particularly conventional plowing, may create a hardpan, or plow sole—that is, a compacted layer just below the zone disturbed by tillage. Such layers are more prevalent with increasing levels of mechanization; they reduce crop yields and must be shattered, allowing water to be stored in and below the shattered zone for later crops. Tillage is also associated with the loss of fertile topsoil through erosion, a serious threat to the longevity of arable land. Primary tillage equipment Disc Plow Equipment used to break and loosen soil for a depth of 15 to 90 cm (6 to 36 inches) may be called primary tillage equipment. It includes moldboard, disk, rotary, chisel, and subsoil plows. The moldboard plow is adapted to the breaking of many soil types. It is well suited for turning under and covering crop residues. There are hundreds of different designs, each intended to function best in performing certain tasks in specified soils. The part that breaks the soil is called the bottom or base; it is composed of the share, the landside, and the moldboard. When a bottom turns the soil, it cuts a trench, or furrow, throwing to one side a ribbon of soil that is called the furrow slice. When plowing is started in the middle of a strip of land, a furrow is plowed across the field, and on the return trip a furrow slice is lapped over the first slice. This leaves a slightly higher ridge than the second, third, and other slices. The ridge is called a back furrow. When two strips of land are finished, the last furrows cut leave a trench about twice the width of one bottom, called a dead furrow. When land is broken by continuous lapping of furrows, it is called flat broken. If land is broken in alternate back furrows and dead furrows, it is said to be bedded or listed. Different soils require different-shaped moldboards in order to give the same degree of pulverization of the soil. Thus, moldboards are divided into several different classes, including stubble, general-purpose, general-purpose for clay and stiff-sod soil, slat, blackland, and chilled general-purpose. The blackland bottom is used, for example, in areas in which the soil does not scour easily—that is, where the soil does not leave the surface of the emerging plow clean and polished. The share is the cutting edge of the moldboard plow. Its configuration is related to soil type, particularly in the down suction, or concavity, of its lower surface. Generally, three degrees of down suction are recognized: regular for light soil, deep for ordinary dry soil, and double-deep for clay and gravelly soils. In addition, the share has horizontal suction, which is the amount its point is bent out of line with the landside. Down suction causes the plow to penetrate to proper depth when pulled forward, while horizontal suction causes the plow to create the desired width of furrow. Secondary tillage disc harrow Secondary tillage, to improve the seedbed by increased soil pulverization, to conserve moisture through destruction of weeds, and to cut up crop residues, is accomplished by use of various types of cultivators, harrows, rollers, or pulverizers, and tools for mulching and fallowing. Used for stirring the soil at comparatively shallow depths, secondary tillage equipment is generally employed after the deeper primary tillage operations; some primary tillage tools, however, are usable for secondary tillage. There are five principal types of harrows: the disk, the spike-tooth, the spring-tooth, the rotary cross-harrow, and the soil surgeon. Rollers, or pulverizers, with V-shaped wheels make a firm and continuous seedbed while crushing clods. These tools often are combined with each other. Minimum tillage The use of cropping systems with minimal tillage is usually desirable, because intensive tillage tends to break down soil structure. Techniques such as mulching also help prevent raindrops from injuring the surface structure. Excessive tillage leaves the soil susceptible to crusting, impedes water intake, increases runoff, and thus reduces water storage for crop use. Intensive vegetable production in warm climates where three crops per year may be grown on the same land may reduce the soil to a single-grain structure that facilitates surface cementation and poor aeration. The loosening and granulating actions of plowing may improve soil structure if the plowing is done when the moisture content is optimal; if not so timed, however, plowing can create unfavourable structure. The lifting and inversion of the furrow slice likewise may not always be desirable, because in many cases it is better to leave a trashy surface. The concept of minimum tillage and no-till agriculture has received much attention. One type of minimum tillage consists in seeding small grain in sod that has been relatively undisturbed. Narrow slits are cut in the sod, and seed and fertilizer are placed in the breaks thus formed. Soil normally subject to erosion can be planted to grain this way while still retaining the erosion resistance of the sod. The technique has been successful in preparing winter grazing in southeastern portions of the United States. In another type of minimum tillage, the land is broken and planted without further tillage in seedbed preparation. One approach involves breaking the land and planting seeds in the tractor tracks (wheel-track planting); the tractor weight crushes clods and leaves the seed surrounded by firm soil. Another method consists of mounting a planter behind the plow, thus planting without further traffic and leaving a loose seedbed that is satisfactory in areas where post-planting rains may be heavy. In some areas, where winter rain often comes after wheat is drilled, a rotation of wheat following peas has been successful. After the peas have been harvested, the field is rough plowed, and fall wheat is then drilled in directly. All these methods minimize expense and land preparation, tending to leave the soil rough, which reduces erosion and increases water intake. Somewhat similar systems are employed with row crops, where chemical weed control assists in reducing need for cultivation. Mulch tillage Mulch tillage is a system in which crop residues are left on the surface, and subsurface tillage leaves them relatively undisturbed. In dryland areas, a maximum amount of mulch is left on the surface; in more humid regions, however, some of the mulch is buried. Planting is accomplished with disk openers that go through several inches of mulch. Since mulch decomposition may deprive the crop of nitrogen, extra fertilizer is often placed below the mulch in humid areas. In rainy sections, intercropping extends the protection against erosion provided by mulches. Intercrops are typically small grains or sod crops such as alfalfa or clover grown between the rows of a field crop that reach maturity shortly after the field crop has been established and furnish mulch cover for a long time. See also green manure. If growth of the intercrop competes with the main crop for moisture and nutrients, that growth may be killed at seeding time or soon thereafter by undercutting with sweeps. Tillage in dry areas must make maximum use of scanty rainfall. The lister (doublemoldboard) plow, or middlebreaker, is here used to make water-impounding ridges that promote infiltration. SECTION CONTENTS: Defining Tillage Systems Effects of Tillage on Plants & Soils Fertilizer Application Methods Nitrogen Lime Phosphorus and Potassium DEFINING TILLAGE SYSTEMS The way in which tillage systems change fertilization practices is a complex issue. Tillage systems are sequences of operations that manipulate the soil in order to produce a crop. Operations include tilling, planting, fertilization, pesticide application, harvesting, and residue chopping or shredding. The ways in which these operations are implemented affect the physical and chemical properties of the soil, which in turn affect plant growth. 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