AGR 111 Fundamentals of Agronomy Notes PDF

AGR 111 : Fundamentals of Agronomy (2+1) Extended Syllabus Theory : Agriculture: Latin words-ager and cultura, definition, art, science and business of crop production; importance and scope of agriculture; spheres of agriculture. Agronomy and its scope: Greek words-agros and nomos, definitions, science of manipulating crop environment, scope of agronomy, principles of agronomy; relation of agronomy to other branches of agricultural sciences-Soil Science, Crop Physiology, Agricultural Microbiology, Entomology and Plant Pathology. History of agricultural development in India and Karnataka: Ancient Indian agriculture-Indus valley civilization, historic developments in agriculture during British period-establishment of botanical gardens, famine commission, establishment of IARI, Royal commission on agriculture, establishment of ICAR and its objectives, All India Coordinated Research Projects, NSC, National demonstration programmes, Green revolution, establishment of DARE, command area development, NARP, NABARD, NAEP, NATP, NAIP, KVK; Agriculture education in India-establishment of agricultural colleges, state agricultural universities, deemed universities; national agricultural research system-central research institutes, project directorates, national bureaus, AICRP, state agricultural universities and central agricultural universities; agricultural research, education and extension in Karnataka-establishment of farm universities, research stations and KVK. Factors affecting crop production: Genetic factors and environmental factors- climatic, edaphic, physiographic, biotic and anthropic factors; climatic factors- precipitation, solar radiation-photoperiodism, short day plants, long day plants and day neutral plants, significance of photoperiodism in crop production, temperature-cardinal points, vernalization, temperature stresses; wind-effect of high wind velocity on crop; atmospheric humidity; atmospheric gases; edaphic factors- soil moisture, soil air, soil temperature, soil mineral matter, soil organic matter, soil organisms and soil reaction; biotic factors-insect pests and diseases, beneficial microorganisms and insects; physiographic factors-topography; anthropic factors-human activities. Classification of crops: According to place of origin, botanical classification-based on life cycle, family and cotyledons; based on pollination-self-pollinated crops, cross pollinated crops and often cross pollinated crops; seasonal classification of crops - kharif, rabi and summer crops, based on temperature-warm season and cool season crops; agricultural/agrarian/economic classification-cereals, millets, oilseed crops, pulses, fibre crops, forage crops, sugar and starch crops, spices and condiments, narcotics and beverages; agronomic classification/classification according to cultural requirements- according to the suitability of soil textural classes, tolerance to the problematic soils, tillage requirement, depth of root system, water supply, method of planting, length of field duration; special purpose crops- catch crops, restorative crops, exhaustive crops, paira crops, smother crops, cover crops, nurse crops, guard crops, trap crops, mulch crops, cash crops, warehouse crops, truck crops, cole crops, silage crops, soiling crops, green manure crops. Soil and its components, properties, fertility and productivity and their management-Definition of soil, importance of soil, soil composition, soil texture, soil structure, soil water, soil air, soil organic matter, soil microorganisms, soil temperature, soil pH, soil porosity, soil bulk density, soil particle density; definition of soil fertility and productivity, difference between soil fertility and soil productivity, factors affecting soil fertility- natural and artificial factors, factors affecting soil productivity-physical, chemical and biological factors; management of soil fertility and soil productivity, main features of good soil management. Tillage and tilth: Meaning, characteristics of good soil tilth, objectives of tillage, influence of tillage on soil physical properties-soil structure, bulk density, soil porosity, soil temperature; types of tillage-preparatory tillage and after cultivation – primary tillage, secondary tillage and layout of seed bed; optimum time, depth and number of ploughings; after cultivation-intercultivation and earthing up; requirement of ideal seed bed. Seeds and sowing: meaning, selection of seed and seed material, characteristics of good quality seed; seed treatment, methods of establishing the crop- direct sowing, transplanting, thinning and gap filling, methods of sowing-broadcasting, sowing behind the plough, drill sowing, dibbling, planting; time of sowing and depth of sowing, nursery techniques for rising seedlings. Crop density and geometry: Meaning of crop density and geometry, optimum plant density, planting geometry-square planting, rectangular planting. Crop nutrition: Criteria of essentiality of plant nutrients-classification of plant nutrients- primary, secondary and micronutrients; role of nutrients in plant growth; manures-organic manures-bulky organic manures-FYM, compost, green manures and concentrated organic manures-cakes, bone meal, blood meal and fish meal; green manures- meaning, types of green manuring-green manuring insitu and green leaf manuring, advantages and limitations of green manuring and characteristics of green manure crops; bio fertilizers-meaning, types of biofertilizers-N fixers, P solubilizing microorganisms; fertilizers-meaning, classification of fertilizers-straight fertilizers, complex fertilizers, mixed fertilizers, low analysis and high analysis fertilizers, solid fertilizers and liquid fertilizers, straight fertilizers-nitrogenous, phosphatic and potassic fertilizers, sources of secondary and micronutrients; fertilizer management-fertilizer dose, sources of fertilizer, methods of fertilizer application-broadcasting, band placement, point placement, deep placement, plough sole placement, fertigation, foliar application; time of fertilizer application-basal and top dressing; INM-meaning and its importance; nutrient use efficiency. Growth and Development of crops: Definition of crop growth and development; germination-biochemical and morphological processes; developmental stages-germination and emergence, seedling growth, maximum vegetative growth stage, primordial differentiation, flowering stage, fruit growth, physiological maturity, harvest maturity; factors influencing growth and development-temperature, soil moisture, depth of sowing, solar radiation, soil aeration, mineral nutrition; plant growth substances-growth promoters and growth retardants; sigmoid growth curve; biological yield, economic yield and harvest index. Crop ideotypes: Meaning, characteristics of ideotypes of cereals and pulses Cropping systems and its principles: Definition, objectives of cropping systems, difference between cropping pattern and cropping system, types of cropping systems-mono cropping and multiple cropping; multiple cropping-intercropping and sequential cropping; intercropping-row inter cropping, mixed intercropping, relay intercropping, strip intercropping, multi-storeyed cropping; sequential cropping-double cropping, triple cropping, quadruple cropping; principles of crop rotation; interactions in intercropping and interactions in sequential cropping. Crop adaptation and Distribution: Meaning of crop adaptation, morphological, anatomical and physiological adaptations of hydrophytes, xerophytes and mesophytes; principles of plant distribution. Crop management technologies in problematic areas: acid soils-Causes for formation of acid soils, ill effects of acid soils on plant growth, management of soil acidity- liming, growing acid tolerant crops, management of phosphatic fertilizers; beneficial effects of liming; salt affected soils-saline, sodic and saline-sodic soils, causes for soil salinity, effects of soil salinity on plant growth, management of saline soils; alkali (sodic) soils-causes for soil sodicity, effects of soil sodicity on plant growth, management of sodic soils-gypsum application, growing of tolerant crops; saline-alkali soils-management of saline-sodic soils; waterlogged soils-management of waterlogged soils. Harvesting and threshing of crops: Meaning, time of harvesting-symptoms of physiological maturity; methods of harvesting-manual and mechanical harvesting, mechanical harvesting-combine harvesters, problems in harvesting; threshing and winnowing-meaning and methods. Weeds: Definition, classification of weeds-based on life cycle, morphology, habitat, cotyledon character, origin, nature of stem and other weed groups-noxious weeds, objectionable weeds, satellite/mimicry weeds, ephemerals and parasitic weeds; harmful effects/losses caused by weeds-crop yield, quality, interference with agricultural implements, harbour pest and diseases, health hazards; characteristics of weeds-seed production, dormancy, self-regeneration, evasiveness, C4 pathway, deep root system; crop weed competition-definition, nature of crop weed competition-competition for moisture, nutrients, light and space; factors influencing on crop weed competition-weed factors, crop factors and management factors; critical period of crop weed competition. Concepts of weed management: Principles of weed control-prevention, eradication, control and management of weeds; weed control methods-cultural methods, physical methods (mechanical /manual), chemical methods and biological methods; chemical method-herbicides-definition, nomenclature, advantages and disadvantages, classification of herbicides based on time of application, selectivity, residual activity, mode of action, mobility; selectivity of herbicides-meaning, herbicide resistance-meaning and management; herbicide adjuvants-meaning; biological methods of weed control-definition, bio agents, advantages and disadvantages; allelopathy-meaning, interaction between crop and weed, weed and weed and crop and crop and integrated weed management. Practical Identification of crops, seeds and fertilizers, Classification of field crops, tillage implements, Study and practice of different methods of ploughing, Study of different methods of sowing, Study of seed drills, intercultural implements, Study of fertilizers, manures and green manures, Calculation of fertilizers and seed rates, Study on seed germination and plant population, Preparation of FYM and compost, Participation in ongoing field operations, Study of agro-climatic zones of Karnataka and India. Study and identification of dry land and waste land weeds. Study and identification of garden land, wet land and aquatic weeds. Calculation of herbicide formulations, doses and their spray. Reference books 1. Balasubramanian, P. and Palaniappan, S.P., 2001, Principles and practices of Agronomy, Agrobios, Jodhpur- 342 002 2. Gopal Chandra De, 1997, Fundamentals of Agronomy. Oxford & IBH Publishing Co. Pvt. Ltd., New Delhi. 3. Guptha, O.P., 2007, Modern Weed management, Agrobios, Jodhpur 4. Reddy, S.R., 1999, Principles of Agronomy, Kalyani Publishers, New Delhi. 5. Yellamanda Reddy, T. and Shankara Reddy, G.H., 2012, Principles of Agronomy, Kalyani Publishers, New Delhi Evaluation Pattern Particulars Max. Marks Mid-term 30 Practical record 05 Practical Examination 10 Attendance 05 Final theory examination 50 (external) Total marks 100 INTRODUCTION TO AGRICULTURE Agriculture: The term agriculture is derived from two Latin words ager or agri meaning soil and cultura meaning cultivation. Agriculture is a broad term encompassing all aspects of crop production, livestock farming, fisheries, forestry etc. Agriculture in its widest sense can be defined as the cultivation and /or production of crop plants or livestock products. It is synonymous with farming: the field or field dependent production of food, fodder and industrial organic materials. Agriculture is a branch of applied science. It is the art of farming including the work of cultivating the soil for producing crops and raising livestock. There are three main spheres of agriculture ✔ Geoponic - meaning cultivation in earth, ✔ Hydroponic - meaning cultivation in water ✔ Aeroponic - meaning cultivation in air Agriculture can also be defined as an art, science and business of producing crops and livestock for economic purposes. Agriculture is a productive unit where in the natural resources like land, light, water and temperatures are integrated into a single primary unit i.e crop plant which is indispensable for human beings. The secondary productive units of agriculture are animals including livestock, birds and insects which feed on the primary units and provide concentrated products such as meat, milk, wool, eggs, honey, silk and lac. The important cultural energies utilized for the production and protection of agricultural commodities are Natural resources: Land, water, light and other resources of environment. Added resources: ✔ Irrigation and drainage ✔ Organic, biological and mineral fertilizers, chemicals ✔ Farm equipments and draft power. These are used to maximize the productivity per unit time, water, land, labour and rupee invested. The word Agriculture may be expanded as Activities on the Ground for Raising Intended Crops for Uplifting Livelihood Through the Use of Rechargeable Energies. Agriculture as an art, science and business and Branches of agriculture: Agriculture as an art: Learning by doing and gaining experience. Art is concerned with skill and experience. It is inherited by seeing parents or elders through experience. Agriculture tells us how to perform and operation like sowing, weeding etc in a skill full manner. Agriculture primarily requires physical skill. Physical skill is inherited by doing physical work with perfect execution. E.g. opening a straight furrow, Leveling the field, sowing seed, application of manures and fertilizers etc. Art of agricultural requires secondarily mental skill. Mental skill: Decision making Eg. Selection of crops for a particular area, Deciding the time of operation, timing of production to get better returns, choosing of low cost / no cost inputs etc. Agriculture as a Science: Science is systematic study of happenings of anything. Scientific principles were used in agriculture for increasing production and quality of crops. Several scientific advances have been made in all branches of agriculture which are systematized to increase crop production and achieve self sufficiency. Eg. Plant breeding and Bio-technology – Developed many varieties suiting to various soils, climate and consumer tastes. Agronomy – Developed improved crop production practices like management of soils, fertilizers etc. Other disciplines – use of pesticides, labour saving machinery, satellite and remote sensing in weather forecasting etc. Together, all these contributed for self sufficiency. Agriculture as a Business: Agriculture in developed countries is a business driven process. The farmers in these countries cultivate the crops to earn higher income with less investment and agriculture is practiced on a business line and land is considered as workshop or factory to generate returns. Mechanization and commercialization have been introduced in these countries to get maximum profit. Where as in developing and under developed countries, agriculture is considered as a way of life and practicing on a subsistence level. Traditional farming is handed over from father to son without any effort to increase production. However, with improvement in literacy rate, WTO, GATT, Agriculture in these countries are assuming as a business enterprise. Similar to the industry, agriculture has many problems like, Excessive / deficit in production as it is controlled by several factors viz., climate. Management Consumer taste and preferences Trade Taxation Employer and employee relationship. Economic interdependence – relationship between farmers Vs merchants & Transport. Hence, Agriculture is considered as a business. Difference between Agriculture and Industry Sl. No. Agriculture Industry Biological process in which plants convert solar 1 Mechanical process energy to chemical energy Primary products of agriculture is organic in 2 Majorly inorganic nature Primary resources are environment, plant, water Depends on agriculture for 3 and air raw materials Can be protected from Subjected to natural calamities and production is 4 natural calamities and not under control production can be controlled BRANCHES OF AGRICULTURE: Major branches: Agril. Agril. Plant 1 Agronomy 5 9 Engineering Pathology Genetics & Plant 2 6 Agril. Icrobiology 10 Agril. Economics Breeding Soil Science & 3 Agricultural 7 Crop Physiology 11 Agril. Statistics Chemistry Agril. 4 8 Plant Biotechnology Entomology Allied branches: 1 Horticulture 3 Animal Science 5 Agricultural Engineering 2 Forestry 4 Fishery 6 Home Science Science 1. Agronomy – It deals with the production management of various crops, which includes food crops, fodder crops, fiber crops, sugar, oil seeds, etc. 2. Horticulture – Branch of agriculture deals with the production of flowers, fruits, vegetables, ornamental plants, spices, condiments and beverages. 3. Forestry – It deals with large-scale cultivation of perennial trees for supplying wood, timber, etc. and also raw materials for industries. 4. Animal Husbandry –Husbandry is the rearing of various animals for meat, milk, wool, draft energy etc. 5. Fishery Science – It is for marine fish and inland fishes including shrimps and prawns. 6. Agricultural Engineering – It is an important component for crop production and horticulture particularly to provide tools and implements. It is aiming to produce modified tools to facilitate proper animal husbandry and crop production. 7. Home Science – It deals with the effective conversion of raw produce into consumable with value addition. Scope and Importance of Agriculture: Agriculture plays a key role in the overall economic and social well being of the country. Though the share of agriculture in both GDP and Employment has declined overtime, agriculture still forms the backbone and occupies a pride of place of the country. 1. Agriculture contributes 15.87 % the Gross domestic Product. The GDP was declined from 1950-51 Agriculture contribution to GDP was 55 % 1980-81 – 37.6 % 1999-2000 – 25 % 2006-07 – 18.5 % 2008-2009 – 15 % 2012 -13 – 14.62 % 2014-15 – 17.1 % 2015-16 – 17.6 % 2017-18 – 17.32 % 2018-19 – 15.87 % 2. Provides livelihood support for more than half of the population in the country. The sector provides employment to 50 % of the India’s work force. 3. Agriculture has been the source of raw material for industries. Majority of the industries depending on agriculture for their raw materials. Eg: Textile (Cotton, Jute), Sugar (Sugarcane, Sugar beet), Small & medium scale industries like soaps, dyes, medicines, vitamins, preservation of fruits and vegetables, dhal milling, rice husking, Jaggery making, oil crushing, handlooms etc. 4. It provides large part of market for industrial goods viz., seeds, fertilizers, pesticides, implements, machines like pump sets, trucks, tractors, power tillers, sprayers etc. 5. Support roadways, railways, airways and shipways for transport of inputs & produce. 6. Provides a large portion of India’s export. Agriculture Provides 15% of the national exports. The commodities exported are tea, coffee, sugar, cashewnut, spices, tobacco, cotton etc. 7. Agriculture maintains food and nutritional security and in turn national security. Satisfactory agriculture Production brings peace, prosperity, harmony, health and wealth. “A man without food – for 3 days will quarrel a week will fight – for a month will die” 8. Agriculture and allied sectors like horticulture, animal husbandry, diary & fishery have an importance in improving economic conditions, health and nutrition of human being Agricultural growth can be witnessed by increased food grains from 50 to 281.37 m.t. The estimated production of major crops during 2018-19 is as under: Food grains –283.37 million tonnes. Rice – 115.63 million tonnes. (record) Wheat – 101.20 million tonnes (record) Nutri / Coarse Cereals – 43.33 million tonnes. Maize –27.82 million tonnes. Pulses –23.22 million tonnes. Gram – 10.09 million tonnes. Tur –3.50 million tonnes. Oilseeds –31.42 million tonnes. Soybean – 13.74 million tonnes Rapeseed and Mustard – 8.78 million tonnes Groundnut – 6.50 million tonnes Cotton – 27.59 million bales (of 170 kg each) Sugarcane – 400.37 million tonnes (record) Per Capita availability of food for per person: ✔ Total cereals – 374.69 gram/person/day Rice – 175.4 g Wheat – 145.1 g Other cereals – 54 g ✔ Pulses – 48 g/p/d ✔ Fruits & vegetables -522 g/p/d Fruits – 172 g/p/d Vegetables – 350 g/p/d ✔ Availability of milk -263 g/p/d This has happened mainly because of revolutions with development of technology. The major revolutions are Green Revolution - Food grains (50 to 215 mt) White Revolution - Milk (17 to 70 mt) Blue Revolution - Fish (0.75 to 5.0 mt) Yellow Revolution - Oilseeds (5 to 25 mt) Geometrical growth of population resulted in 1.2 billion in India. However, food grains production is moving arithmetically. The food grains demand by 2025 is estimated at 235 mt over different years. In future, agricultural development in India would be guided not only by the compulsion of improving food and nutritional security, but also by the concerns for environmental protection, sustainability and profitability. We need to achieve the food grains production growth rate by 2.7% to meet the population growth rate of 2.2%. This is possible through 1. Increasing the area under HYV and Hybrids 2. Adoption of improved production technology 3. Increasing area under irrigation 4. Efficient and integrated management of manures and fertilizers 5. Adoption of suitable crop / cropping system and formulation of cropping zones 6. Attentions to develop integrated pest management timely to avoid losses 7. Rain water management – efficient conservation & harvest followed by judicious use 8. Transfer of technology from lab to land efficiently and timely. INTRODUCTION TO AGRONOMY Agronomy: The term Agronomy is derived from two Greek words ‘Agros’ meaning ‘Field’ and ‘Nomos’ meaning ‘Manage’. Agronomy is a branch of applied science deals with the principles and practices of soil, water and crop management. Norman (1980) defined agronomy as ‘The science of manipulating the crop environmental complex with dual aims of improving agricultural productivity and gaining a degree of understanding of the process involved’. In recent times, Agronomy has assumed a newer dimensions and can be defined as ‘A branch of agricultural science that deals with the methods which provide favourable environment to the crops for higher productivity. Role of Agronomist Agronomist exploits the knowledge of the basic and applied sciences to maximize crop production at minimum cost. Agronomists are concerned with deriving efficient technology of crop production activities like. a. Land Preparation: Developing efficient and economic field preparation methods depending on crop, season and resource availability. Developing machineries in co- ordination with Agricultural Engineers. b. Selection of crops: Involved in selecting suitable crop and variety in accordance with the season, soil and farmers preference. c. Sowing / Planting: Develop efficient method of sowing / planting and standardized spacing / plant geometry to maintain optimum plant population and in turn better yield. d. Nutrient management: Identify various nutrients required by the crop taking crop demand and soil fertility in to consideration. He is also responsible for deriving optimum time and method of application of these nutrients. e. Weed management: Agronomist is responsible for selecting better weed management practices viz., mechanical / physical or cultural / agronomic or biological or chemical or integration of 2 or more methods. f. Irrigation management: Selection of proper irrigation method, time and quantity of application based on crop water need and its availability. g. Crop planning / cropping system: Identifying the crop sequence, inter / mixed cropping for efficient utilization of available resources to maximize farm income. h. After care: Management of crop after planning / sowing till harvesting including the schedule of plant protection measures, interculture etc. i. Harvesting and Processing : Responsible for deriving efficient method and time of harvesting & processing. j. Decision making: on marketing / sale of produce i.e., Time and place of marketing. Overall, Agronomist is like a Physician HISTORY OF AGRICULTURE: It is supposed that man was evolved on earth about 15 lakh years ago. This man started to move by standing erect on his feet. Such man has been called Homo erectus. Later the modern man was evolved called Homo sapiens (Sapiens means learning habit) due to his continuous learning habit. It is difficult to trace the exact period of beginning of agriculture. Archeological evidences indicated that, agriculture started about 50,000 years ago. Hunting was the primary source of food in olden days and was prevailed for long time. Pastoral obtained his food through domestication of some animals like dogs, horse, cow, buffalo etc. They live in the periphery of the forest and migrate from one place to another in search of food. It was not comfortable and they started enjoying by settling at one place near the river and started agricultural system. Agricultural systems of the world can be divided into 4 groups. Shifting cultivation , Simple sedentary cultivation , Simple plough cultivation , Advanced / modern agriculture. a. Shifting cultivation: Moving from one place to other specially the river beds by clearing forest through fire and broadcasting the crop seeds like paddy, chilli, redgram etc. it is also called as Jhumming or Jhum Cultivation. b. Simple sedentary cultivation: People use to dig pits / holes with sharp spade or pickaxe and plant / sow seeds. It is common in Asian countries and crops cultivated are banana, coconut, arecanut, root tubers etc. c. Simple plough cultivation: Practiced with development of small local ploughs and animal draft power. Eg: Rice cultivation. d. Advanced / modern agriculture: It is based on modern machineries and adoption of technologies developed over time. The Agriculture history can be divided into 3 Phases. i) Ancient period (From 800 BC to the fall of Rome – 476 AD) ii) Medieval period (From 476 AD to 1600 AD) iii) Modern period (From 1600 AD onwards) i) Ancient period: From 800 BC to the fall of Rome – 476 AD Period Event Before 10,000 BC Hunting & gathering of fruits, grains in forest area and animals 7,500 BC Shifting cultivation of crops – Wheat & Barley 3,400 BC Invented wheel (out of stone) 3,000 BC Bronze used for making tolls 2,900 BC Invented plough, started irrigated farming 2,300 BC Cultivation of chickpea, cotton & mustard 2,200 BC Rice cultivation 1,500 BC Sugarcane cultivation 1,400 BC Used iron for making tools 1,000 BC Use of iron plaogh 430 to 330 BC Xenophan – Greek historian mentioned about ploughing of green material to enrich soils 234 to 149 BC Cato gave importance to ploughing and manuring 70 to 19 BC Virgil mention about crop rotation and inclusion of legumes to enrich soil fertility. ✔ Mentions about agriculture has also been made in Vedas (Rigveda, Yajurveda, Atharvanaveda and Samaveda). ✔ Rigveda: Green cultivation, cattle rearing, use of ploughs & sickles ✔ Atharvanaveda: Different crops grown in different season ii) Medieval period: During the period of Buddist’s, Gupta’s, Maurya’s and Magada’s, mention has been made on agriculture. For instance a. A Greek ambassador Megasthanis came to India and mentioned how Indian people giving importance to maintain soil fertility and crop production b. Kautilya, a famous economist mentioned the role of a king in protecting agriculture. He emphasized for drying seeds / grains and their storage for future use. c. Saint Manu, in his ‘Manusmrithis’ has mentioned about the punishment given against implement theft. d. Saint Parasara (1000 AD) in his book ‘Krishiparasara’ mention the operations for paddy for different season. He emphasized manuring, ploughing, puddling, thinning, weeding and irrigation. e. Peter Decresenzi (1230 – 1307 AD) collected many literatures related to Agronomy in his book ‘Opus Ruralium Kamo Daram’. Hence, he is considered as ‘Father of Agronomy’. iii) Modern period / Development of scientific agriculture Scientific agriculture was started during 16th century. Experimentation technique was started by Francis Bacon (1561-1624 AD). He concluded from his study that water is the principle element for plant. Van Helmont (1572- 1644 AD) conducted a pot experiment on willow tree, popularly known as ‘Willow Tree Experiment’. He took a willow plant of weight 5 Pounds and planted in a pot containing 200 pounds soil. The plant was monitored for 5 year by continuous watering. By the end of 5th year, the willow tree weighed 169 Pounds and the weight of soil was 198 Pounds. He concluded that water is the solw requirement for plants. Jethrotull (1674-1741) mentioned soil particles are essential for plant growth. He developed ‘ Horse hoe’ for tillage. He suggested providing more soil particles to plant by tilth and addition of animal excreta and manures to soil, which make it friendlier for plant growth. He invented ‘seed drill’ in 1731 for row sowing. He also published a book ‘Horse hoeing husbandry’ in 1733. He is considered as ‘Father of Tillage’ Arthur Young (1741-1820) published ‘Annals of Agriculture’ comprehending available literature on agriculture. Priestly (1780) mentioned that plant take CO2 from carbonic acid of soil and give up O2. Theodore De Saussure (1804) concluded from his experiment that a. Plants absorb CO2 from atmosphere and not from soil b. ‘N’ essential for plant growth taken from soil c. Plant roots are selective in absorption and absorb only water from soil leaving salts. Hence, salts accumulate in soil. d. Mineral matters are not synthesized in the plants but are absorbed by roots from the soil. The large scale field experimentation was started by JB Boussingault (1834). He is recognized as ‘Father of Field Experimentation’. He worked on mineral nutrition of plants. Justas Van Leibig, a german scientist considered as ‘Father of Agricultural Chemistry’ opinion that, growth of plant was proportional to the amount of mineral substance available in the soil. He proposed a law called Leibig Law of Minimum. It states that ‘The growth of plant is limited by the plant nutrient which is present in smaller quantity while all other being adequate’. JB Lawes & JH Gilbert (1843), started an agricultural experiment station to conduct long term fertilizer trial and to test the superphosphate they developed by the action of rock phosphate and H2SO4 at Rothamsted. Gregor Johm Mendal (1856) discovered laws of heredity. Charles Darwin (1876) proposed theory of evolution and inheritance of acquired character. PMA Millerdet (1880) discovered ‘Bordeux Mixture (CuSO4 + Ca(OH)2 + H2O :: 1:1:100 ratio) to control downy mildew in grapes. Thomas Malthus (1898) proposed theory of population growth, which states “Population in India is growing in geometrical and food grain in arithmetical progression. Human would run-out of food inspite of advances in agriculture due to limited land and yield potential of crops”. Blackmann (1905) Proposed Theory of Optima and Limiting Factor. Which states that ‘When a process is conditioned as to its rapidity by a number of separate factors, the rate of the process is limited by the pace of slowest factor’. Mitscherlich (1909) proposed Law of Diminishing Returns, which states ‘Increase in growth with each successive addition of the limiting element is progressively smaller and the response is curvilinear’. Wilcox (1929) proposed Inverse Yield Nitrogen Law. It states that ‘The growth or yielding ability of any crop plant is inversely proportional to the mean nitrogen content in plant’. He also published a book called Wilcox Agro-Biology. Agricultural Research / Education in India: No agricultural experiment stations were initiated in India till 1903. there was famine in 1877, 1889, 1892, 1897 and 1900 in India caused decreased population due to scarcity of food and death. Lord Curzon (1898-1905) constructed great canal in western Punjab. Famine commission appointed in 1888, 1898 and 1901 stressed the importance of agricultural research. As a consequence, he started Imperial Agricultural Research Institute in 1905 at Pusa, Bihar. His period is called as ‘Golden Period of Agriculture’. During his regime, Agricultural Colleges were started at Poona, Dehradun, Saidapet (Coimbatore) Province. Also Hebbal Farm at Bangalore in Mysore Province was started in 1899. Later it was upgraded as Agricultural school in 1912-13 to offer Diploma in Agriculture. Due to earthquake in 1934 at Pusa, Bihar, Imperial Agricultural Research Institute was shifted to New delhi in 1936. Later, it was renamed as Indian Agricultural Research Institute (IARI). Which is one of the largest research institute in the country and also taking Post-Graduate education. Further, based on the 1928 Royal commission recommendation, Imperial Council of Agricultural Research was started at New Delhi in 1929. which was later changed as Indian Council of Agricultural Research (ICAR) with 3 main objectives. 1. To Co-ordinate the education in agriculture, animal husbandry, fishery, research and its application (Extension) 2. To finance various research institutes, Agril. Universities, schemes/ projects all over the country 3. Disseminate the knowledge gained by research through literature. ICAR is the sole body, which controls all Agricultural Research Institutes in India. It paved way for Green Revolution. Several research institutes both at National, International level were set up to take location specific research (Appendix – I) After independence, ICAR adopted to Land Grant Colleges. The first Land grant College was started at Panth Nagar (Uttaranchal) in 1962. University of Agricultural Sciences, Bangalore was established in 1965 with Three objectives viz., Teaching, Research & Extension. There are 71 Universities under ICAR with research institutes on its own. Presently, in Karnataka, 6 Universities are coming under ICAR. UAS (Bangalore) was bifurcated in to 2 in 1986 as UAS (Bangalore) and UAS (Dharwad). Considering the essence of Animal & Dairy research, Animal / Dairy components were separated from both the Universities to formulate a separate University ‘Karnataka, Veterinary, Animal and Fishery Sciences University’ Headquartered at Bidar in 2004. As of now, the Teaching campuses of UAS (Bangalore) are : Degree Campuses B.Sc. (Hons.) Agriculture Bangalore (1946), Mandya (1991), Hassan (2006) & Chintamani (2007) Chamaraj Nagar (2019) B.Sc. (Hons.) Sericulture / B.Sc. (Hons.) Chintamani (1995) Agricuture B.Sc. (Agri. Engineering) Bangalore B.Sc. (Agri. Business Management) Bangalore B.Tech. (Biotechnology) Hassan (2007) B.Tech. (Food Technology) Hassan (2007) Research: With the prime mandate of Research, Zonal Agricultural Research Stations (ZARS) were established in all the Agro-climatic Zones with 2-4 affiliated Agricultural Research Station (ARS). The Research stations of UAS (B) are given in Appendix – II. Extension : Krishi Vignana Kendra (KVK’s) were established to transfer the technology from lab to land beside training the farmers. There are 7 KVK’s functioning under UAS, Bangalore besides 2 under NGO’s sponsored by ICAR & 1 directly under ICAR and are listed in Appendix - III APPENDIX - I 1947 - CTRI at Rajamundry (Tobacco) 1949 - CPRI at Patna, 1956 - CPRI shifted to Simla 1950 - IARI established at New Delhi 1952 - IISR at Lucknow (sugarcane) 1955 - NDRI at Karnal (Dairy) 1956 - PIRRCOM Project for intensification of regional research on cotton, oilseeds and millets. (Central Cotton Research Institute – Regional Centre) 1959 - CAZRI at Jodhpur (Rajasthan) (Arid zone) 1960 - IRRI, Los Bonas, Phillippines 1962 - IGFRI at Jhansi Uttar Pradesh; G.B. Pant Nagar Agricultural Univeristy and technology at Pant Nagar. 1963 - CTCRI, Trivandrum (Tuber crops) 1965 - IAAP (Intensive Agriculture Area Programme) 1969 - CSSRI (Central soil salinity Research Institute) at Karnal (Haryana) 1970 - CPCRI at Kasargod (Kerala) (Plantation crops) / Drought Prone 1972 - ICRISAT at Patancheru, Hyderabad National Institutions for Agricultural Research: 1. Central Arid Zone Research Institute (CAZRI), Jodhpur, Rajasthan. 2. Central Institute for Cotton Research (CICR), Nagpur, Maharastra. 3. Central Institute of Agricultural Engineering (CIAE), Bhopal, Madhya Pradesh. 4. Central Institute of Fisheries Technology (CIFT), Cochin, Kerala. 5. Central Marine Fisheries Research Institute (CMFRI), Ernakulam, Cochin, Kerala. 6. Central Plantation Crops Research Institute (CPCRI), Kasaragod, Kerala. 7. Central Potato Research Institute (CPRI) Simla. Himachal Pradesh. 8. Central Research Institute for Dryland Agriculture, (CRIDA), Hyderabad, Andhra Pradesh. 9. Central Research Institute for Jute and Allied Fibres (CRIJAF), Barrackpore, West Bengal. 10. Central Rice Research Institute (CRRI) Cuttack, Orissa. 11. Central Soil and Water Conservation Research and Training Institute. (CSWCRTI), Dehradun, Uttar Pradesh. 14. Central Soil Salinity Research Institute (CSSRI), Karnal, Haryana. 15. Central Tobacco Research Institute (CTRI) Rajamundry. Andhra Pradesh. 16. Central Tuber Crops Research Institute (CTCRI), Thiruvananthapuram, Kerala. 17. Indian Agricultural Research Institute (IARI), New Delhi, 18. Indian Agricultural Statistics Research Institute (IASRI), Pusa, New Delhi. 19. India Grassland and Fodder Research Institute (IGFRI) Jhansi, Uttar Pradesh. 20. Indian Institute of Horticultural Research (IIHR), Hassaraghatta, Bangalore, Karnataka. 21. Indian Institute of Pulses Research (IIPR), Kanpur, Uttar Pradesh. 22. Indian Institute of Soil Science (IISS) Bhopal, Madhya Pradesh. 23. Indian Institute of Spices Research (IISR), Calicut, Uttar Pradesh. 24. Indian Institute of Sugarcane Research (IISR), Lucknow, Uttar Pradesh. 25. Indian Lac Research Institute (ILRI), Ranchi. Bihar. 26. Indian Veterinary Research Institute, (IVRI) Izat nagar, Uttar Pradesh. 27. Jute Technological Research Laboratories (JTRL), Calcutta, West Bengal. 28. National Bureau of Plant Genetic Resources (NBPGR), IARI Pusa Campus, New Delhi. 29. National Bureau of Soil Survey and Land Use Planning, (NBSS & LUP) Nagpur, Mhr. 30. National Dairy Research Institute (NDRI), Karnal, Haryana. 31. National Research Centre for Agroforestry (NRCAF), Jhansi, Uttar Pradesh. 32. National Research Centre for Banana (NRCB), Tiruchirappalli, Tamil Nadu. 33. National Research Centre for Oil Palm (NRCOP), West godavari District, AP. 34. National Research Centre for Weed Science (NRCWS) Jabalpur, Madhya Pradesh. 35. Sugarcane Breeding Institute, (SBI) Coimbatore, Tamil Nadu. International Institutions for Agricultural Research 1. Centro International de Agricultura Tropical (CIAT) Columbia. 2. Central International de la Papa (CIP) (International Institute of Potato) Lima, Peru. 3. Centro International de Mejoramiento de Maiz Y Trigo (CIMMYT) (International Centre for maize and Wheat Improvement) Londres Mexico, D.F.Mexico. 4. International Centre for Agricultural Research in the Dry Areas (ICARDA), Syria. 5. International Crops Research Institute for the Semi Arid Tropics (ICRISAT), Hyderabad. 6. International Food Policy Research Institute (IFPRI), Washington, D.C. U.S.A. 7. International Institute of Tropical Agriculture (IITA) Nigeria. 8. International Laboratory for Research in Animal Diseases (ILRAD), Nairobi, Kenya. 9. International Service in National Agricultural Research (ISNAR), Netherlands. 10. International Livestock Centre in Africa (ILCA), Addis Ababa, Ethiopia. 11. West Africa Rice Development Association (WARDA) Ivory coast, Liberia. 12. International Rice Research Institute (IRRI), Manila, Philippines. 13. Asian Vegetable Research and Development Centre (AVRDC) P.O.Box 42, Shanhau, Tasnan 941, Taiwan, Republic of China. 15. International Centre of Insect Physiology and Ecology (ICIPE) Nairobi, Kenya. 16. International Council for Research in Agro Forestry. (ICRAF) Nairobi, Kenya. 17. International Irrigation Management Institute (IIMI), Colombo, SriLanka. 18. Consultative Group on International Agricultural Research (CGIAR), N.W.Washington. D.C.U.S.A. Appendix – II : List of Research Stations under UAS, Bangalore Zone 4: Central Dry Zone 5: Eastern Zone 6: Southern Zone 7: Southern Zone Dry Zone Dry Zone Transitional Zone ZARS, VC farm ZARS. GKVK Mandya ARS, Tiptur MRS, Hebbal ARS, Madenur ARS, Gunjevu ARS, Arasikere ARS, Chintamani ARS, Nagenahally ARS Pavagada ARS, Balajigapade ARS Kunigal ARS Nelamakanahalli Appendix – III : List of Krishi Vignana Kendra’s under UAS, Bangalore District KVK Hassan KVK, Kandli Tumkur KVK, Tiptur Mandya KVK, Mandya Kolar KVK, Chintamani Chamarajanagar KVK, Chamarajnagar B’lore Rural KVK, Doddabalapur Ramanagar KVK Namanagar NGO KVK Mysore JSS KVK, Mysore Operating Distrcits of UASB:10 districts with 4 zones Bangalore Rural, BangaloreUrban, Kolar,Chikkaballapur, Ramanagar,Mysore,Mandya,Hassan,Tumkur,Ramanagara FACTORS AFFECTING CROP PRODUCTION / PLANT GROWTH: Higher plants demand certain basic things for their growth. As many as 52 factors (basic things) influencing crop growth have been identified. Only 7% of the world land is adopted for crop production, of which 100% of the land have sufficient CO2 in the atmosphere & sunlight 83% have favorable temperature 64% have favorable topography 46% have reliable rainfall 40% have satisfactory fertile land But only 7% have combination of these factors to make feasible crop production without advanced technology and this is also declining still in recent times. The factors influencing crop growth / production can be broadly grouped into 2 group Crop growth Internal factors External factors (Genetic or Hereditary) (Environmental) i. Climatic ii. Edaphic iii. Biotic iv. Physiographic v. Socio-economic Genetic factors: The increase in crop yields and other desirable characters are related to genetic make up of plants. Breeders and Bio-technologists have incorporated many desirable characters and developed HYV and hybrids. The characters considered are: 1. High yielding ability 2. Early maturity 3. Resistance to lodging (Strengthening of stalk) 4. Tolerance to drought, flood and salinity 5. Tolerance to insect pests and diseases 6. Chemical composition of grains (high percentage of oil, protein etc.) 7. Quality of grains (fineness, coarseness, etc.) 8. Quality of straw (sweetness, juiciness, etc.) These characters are inherited and transferred from one generation to another through genes. External or Environmental Factors: Crop growth and development is primarily governed by environmental conditions. Success or failure of crop is related to the weather condition that prevails during crop growth. Control of these factors of environment under field condition is more difficult, costly and often impossible. Therefore, it is essential to study these factors in order to cope up with them for better crop growth. The environmental factors are broadly grouped as a) Climatic b) Edaphic c) Biotic d) Physiographic & e) Socio-economic a) Climatic Factors: Climate is a generalized weather or summation of weather conditions over a given region during comparatively longer period. Weather is a state or condition of atmosphere at a give place and at a given time. Climate is weather conditions related to larger areas like zone, state, country etc., and for longer duration like month, season, year etc. The important climatic elements that affect crop production are Precipitation Temperature Atmospheric humidity Solar radiation Wind Atmospheric gases i) Precipitation: Precipitation includes all forms of water that fall on earth from the atmosphere such as rainfall, snow, hail, dew, fog etc. It is the source of water for crop production. Precipitation is resultant of condensation of water vapour evaporated from sea and land surfaces. The process involved in transfer of moisture from land and sea to atmosphere and back is known as hydraulic cycle. Rainfall is the most important factors influences vegetation of a place. Most of the plant water demand is met out with rainfall. Rainfall both in total amount and seasonal distribution greatly affect choice of crops and their growth eg. In heavy and evenly distributed rainfall areas, crops like rice in plains, coffee, tea, rubber in hilly areas can be taken. In low and uneven distributed areas, drought resistance crops like bajra, sorghum, millets can be taken. Both excessive and deficit rainfall affect crop production. Excessive rainfall leads to Soil erosion – loss of nutrient, soil Submergence – affect root respiration / activity Pollen wash – affect pollination & fertilization Crop lodging and grain shedding Deficient rainfall leads to desiccation of plant, reduce yield and result in plant death. About,55% of the world land receive < 51 cm rainfall - Semi arid 20% 51 – 102 cm RF - Sub humid 11% 102 – 152 cm RF - Humid 14% > 152 cm RF - Super humid Water is an indispensable element of plant growth. It performs the following functions i) Constitute of protoplasm (85-90% of actively growing tissue is water) ii) Reagent for many biological activities (Photosynthesis) iii) Acts as solvent for transportation of mineral nutrients iv) Maintains cell turgidity – important for cell division and elongation v) Regulate stomatal movement – important in gas exchange and microclimate. Depending on the water need, the plants are grouped into 3 groups: a) Xerophytes: Plants survive under very low moisture condition and withstand drought even for prolonged period. They are also called as Desert Plants. Eg. Agave. b) Mesophytes: They require normal supply of moisture for their growth and grow well when soil is moist. Eg. Wheat, Maize, Pulses c) Hydrophytes: are water loving plants, grow well only when the soil is wet or full of water. Eg. Rice, Aquatic plants. The water is utilized in photosynthesis results in dry matter production of plants. Which is expressed as Transpiration Co-efficient. Transpiration Co-efficient is the total quantity of water required to produce a unit quantity of dry matter. It varies from plant to plant. Transpiration co-efficient of some of the crop’s are as follows Transpiration Co-efficient Sl. Crop Without With No. fertility fertility 1 Maize 450 330 2 Ragi 250 250 3 Jowar 400 400 4 Rice 1000 800 5 Wheat 850 550 ii) Temperature: Temperature is a measure of intensity of heat energy or the degree of hotness / coolness. Temperature of a place is largely determined by its distance from the equator (latitude) and altitude. The temperature range for maximum growth of agricultural crops lies between 15-40oC. Based on the temperature, the vegetations are grouped as tropical, temperate, taiga, tundra and polar. G r o w Min Opt Max Species and cultivated crop plants differ in their physiological responses to range of temperature. The growth increases with an increase in temperature to a certain extent but reduces after a limit. Every plant community has its own minimum, optimum and maximum temperature range for their growth and development known as cardinal temperature points. Cardinal temperature points are not same throughout the crop growth and vary between germination, growth, flowering and fruiting. The cardinal points of important crops are For germination For growth Crop Minimu Optimu Maximu Minimu Optimu Maximu m m m m m m Rice 13 – 14 28 40 10 32 36 – 38 Wheat 4.0 – 4.5 25 30 – 32 4.5 20 30 – 32 Maize 8 – 10 31 – 35 40 – 44 8 – 10 25 – 30 40 – 43 Sorghu 8 – 10 31 – 35 40 – 44 12 – 13 25 40 m Tobacc 13 – 14 28 40 12 – 14 29 35 o Soil and atmospheric (air) temperature are important from the growth point of plants. Crop production also depends on the temperature during day and night. If the days are warm, increased respiratory loss can be compensated by photosynthesis to some extent. However, if nights are warm, respiratory losses are higher and in turn reduce the crop yield. Some plants require optimum day and night temperature for successful flowering. The response of the plants to rhythmic diurnal fluctuation in temperature is called Thermoperiodism. Eg. Tomato requires 26-27oC day temperature & 17-19oC night temperature. Some plants require a cold stimulus (chill treatment) for flowering. This is done in winter wheat. The cold treatment given to the sprouting seeds to induce flowering is known as Vernalization. Here wheat seeds are subjected to 0oC for about 2-3 weeks before sowing. This is done to save seedling from severe winter damage and to induce flowering. This would change the development of apex from vegetative to reproductive growth called thermo-morpho-genesis. This concept was developed by ‘Lysenco’ – a botanist in Russia. Based on the temperature, the crops are grouped as, 1) Cool season crops: require cool winter period generally grown in winter, the cardinal temperature points of these crops lies between Minimum = 0-5OC, Optimum = 25-30OC, and Maximum = 30-38OC. Eg. Wheat, Barley, Oat, Sugar beet etc 2) Warm season crops: require warm weather and grown in Kharif and summer. Cardinal temperature points of these crops lies between Minimum = 15-20OC, Optimum = 30-38OC, and Maximum = 45-50OC. Eg. Rice, Maize, Sorghum, Sugar cane etc. Influence of temperature on crop growth: Temperature influences crop growth through a. Regulation of bio-chemical reaction b. Uptake of CO2 c. Enzymatic activity d. Chlorophyll synthesis, leaf emergence & expansion e. Influence on growth substances – regulating ratio between growth promoters and retarders f. Photosynthesis and dry matter production g. Crop yield – regulating Photorespiration and other bio-chemical activities, Growing Degree Days: The intensity of growing season is represented by the accumulation of temperature units above the growth threshold. The unit used is degree- days. It is the amount by which daily mean temperature exceeds the stated minimum / base temperature (Temperature at which the activities start). It is also called heat unit and mathematically expressed as n TMax + TMin GDD ∑ { } - Tb = 2 r=1 Where, TMax & TMin = Maximum and Minimum temperature of the day Tb= Base temperature (Rice = 10oC, Wheat = 5 oC, Maize = 10oC). Units of measurement of temperature Temperature is measured either in Fahrenheit (oF), Celsius (oC) or Kelvin (oK) scale and are related as C = 5/9 (F-32) F = 9C/5 +32 K = C + 273 Boiling Point Melting Point Celsius (oC) 100 0 Fahrenheit (oF) 210 32 Kelvin (oK) 373 273 Effect of extreme temperatures on plant growth Extreme high and low temperature causes stress in plants. High temperature stress: 1. Causes reduction in absorption and assimilation of nutrients 2. Affect shoot growth 3. Abortion of pollens – reduce viability and cause female sterility Low temperature stress 1. Survival, cell division and elongation is strongly affected 2. Absorption and translocation of water is affected due to low permeability of water 3. Reduced translocation and gas exchange resulted in poor photosynthetic rate and in turn the crop yield Low temperature also cause the following injury to the crop plants 1. Chilling injury: Plants growing in hot climate, if exposed to low temperature for some time, are found to be killed or injured severely. Eg: Chlorotic condition or bands on leaves of sugarcane, sorghum and maize when exposed for 60 hours at 2 to 40C. 2. Freezing injury: caused in plants growing in temperate region. When the plants are exposed to very low temperature, water in the intercellular spaces is frozen into ice crystals. Further fall in temperature, draws water from the cells, resulting in increased size of ice crystals and death of cells. 3. Suffocation: During winter, the ice or snow form a thick cover over the ground and the crop suffers for want of oxygen. Ice in contact with roots inhibits diffusion of carbon dioxide and the respiratory products may become harmful to plants. 4. Heaving: Injury to plants is caused by a lifting upward of the plant along with the soil from its normal position in temperate regions where snowfall is common. Classification of vegetation based on temperature Class Region Temperature Vegetation Common condition crops Megatherms Equitorial/Tro High temp. throughout Tropical rain Cassava, pical the year rubber, rice Mesotherms Tropicl/SubTr High temp. & winter Tropical Maize, opical low temp deciduous forest sorghum Microtherms Temperate Low temperature Mixed coniferous Wheat, oat, potato Hekistotherm Artic / alpine Very low temperature Alpine Pines s iii) Atmospheric humidity: Humidity refers to the water vapour suspended in the atmosphere. Water vapour is a colourless, odourless, tasteless and consists of very minute water droplets suspended in air. Which is the resultant of the evaporation from soil and water bodies with the solar energy in the form of temperature. When the atmosphere holds maximum amount of water vapour at particular temperature is said to be saturated. Increase in temperature will make the air unsaturated. The evapo-transpiration of water is directly proportional to the difference between the amount of water actually present and the saturation. The difference is termed as Vapour pressure deficit (VPD). The atmospheric humidity is expressed as absolute, specific and relative humidity. Absolute humidity is the actual quantity of water vapour by weight present in a given volume of air Weight of water vapour Absolute humidity (g (g) = m-3) Volume of air (m3) Specific humidity is the weight of water vapour per unit weight of air (including water vapour) Weight of water vapour (g) Specific humidity (g = Weight of air including water vapour kg-1) (kg) Absolute and specific humidity are difficult to measure as they fluctuate greately with temperature. Also, they have little or no effect on crop growth. The extent of evaporation and transpiration depends on the amount of moisture held in the atmosphere. Hence, it is essential to findout the saturation capacity and VPD, which is given by relative humidity. Relative humidity is the ratio between the amount of water vapour present in the air and the amount of vapour required for saturation at particular temperature & pressure and expressed in percentage Water vapour present in air Relative humidity (%) = X 100 Water vapour required for saturation If RH is 100%, there is no evaporation & transpiration and if it is 0%, then there is enormous evapotranspiration. Both these conditions are not congenial for crop growth. RH of around 60% is suitable for most of field crops. Relative humidity is greately influenced by temperature, wind, vegetation and water content in soil. Increased RH - favours growth of many fungi, bacteria, insects affecting crop growth - affect gas exchange through stomata by affecting transpiration & in turn photosynthesis & crop yield. Reduced RH - Increase evapo-transpiration and demand more irrigation. iv) Solar radiation: Solar radiation is the source of energy for all physical processes taking place in the atmosphere. This energy also drives the process of photosynthesis, chlorophyll synthesis, evaporation, heating of soil & air to regulate temperature besides germination, leaf expansion, stem growth, flowering, fruiting etc. More than 70% of solar radiation absorbed by the plant is converted into heat which is essential for transpiration. About 28% of solar energy is utilized in photosynthesis. A constant amount of radiation (1.94 cal cm-2 min-1) is emitted continuously from the sun. The amount of solar energy received per unit area of surface held at right angle to the sun rays at the top of the atmosphere is called solar constant. Light affect plants growth through its intensity, duration and quality. a) Light intensity: The total quantity of light received in unit time can be considered as light intensity, which is expressed in Foot Candles / Lux. The optimum light intensity for most of the crops is around 1700 Lux. There are certain plants which grow luxuriously with high light intensity, such plants are called Heliophytes (Sun-loving) Eg. Sunflower. The plants growing under low light intensity / shade condition are called Sciophytes (Shade loving) eg. Coffee. The light intensity at which the photosynthates produced through photosynthesis is completely made use for its respiration is called Light saturation point. It varies from sciophytes (27 Lux) to heliophytes (4200 Lux). Higher light intensity may disintegrate chlorophyll. b) Quality of light: The process of photosynthesis in green plants depends on quality of light. Radiation up to 250 ήm in UV spectrum is harmful to most of the plants. Though, radiation from 300 ήm is photosynthetically active, visible spectrum (400 – 750 ήm) is more effective. Visible spectrum composed with seven colour range VIBGYOR. Violet - 400 to 435 ήm Green - 490 to 574 ήm Orange - 595 to 626 ήm Indigo - 435 to 460 ήm Yellow – 574 to 595 ήm Red - 626 to 750 ήm Blue - 460 to 490 ήm With in the visible range, the principle wavelength absorbed in photosynthesis are Violet to Blue (400 – 490 ήm) and Orange to Red (595 – 750 ήm). Red light is found most favourable. Radiation above 750 ήm (Infra Red radiation) is harmful to photosynthesis. c) Duration of light: Light intensity and duration determine the amount of light that a plant receives. The length of the day is more important than intensity. The response (Flowering) of the plants to the relative length of day and night is known as photoperiodism. Different species and in some cases different cultivars of the same species responds differently to the length of day and night. The photoperiod required to induce flowering is called critical day length. Based on the photoperiodic response, the plants are grouped as ❖ Long day plants: Crops that reproduce (Flower) normally when the light period is longer than 12 hours. Eg. Rabi Crops – Wheat, Barley, Sugar beet, Potato etc. ❖ Short day plants: Crops that reproduce (Flower) normally when the light period is shorter than critical minimum ( 60 cm): Sugarcane, safflower, lucerne, redgram. F. According to the tolerance to hazardous weather condition i. Frost tolerant: Sugarbeet, beet root, ii. Cold tolerant: Potato, cabbage, mustard iii. Drought tolerant: Bajra, jowar, barely, safflower, castor G. According to water supply i. Irrigated crops: Rice, wheat, pulses, groundnut, berseem. ii. Rainfed / upland crops: Jute, maize, ragi, upland rice, redgram iii. Rainfed but partially irrigated: Bengal gram, wheat, jowar, bajra, mustard, Horsegram iv. Residual / conserved soil moisture: Rapeseed, bajra, barley, safflower, linseed. v. Rainfed with supplemental irrigation: Kharif rice, sugarcane, blackgram. vi. Rainfed with flooded water: Deep water rice, jute, sugarcane, daincha H. According to method of sowing / planting i.Direct seeded crop: Upland rice, wheat, Ragi, jowar, bajra, groundnut etc. ii.Planted crops: Sugarcane, potato, sweet potato, napier, guinea grass. iii.Transplanted crop (after raising seedlings in the nursery) : Rice, ragi, tobacco, brinjal I. According to length of field duration of crops i) Very short duration crops: up to 75 days Pulses ii) Short duration crops: 75 – 100 days Sunflower, cauliflower, uplandrice iii) Medium duration crops: 100-125 days Wheat, jowar, bajra, groundnut, jute. iv) Long duration crops: 125-150 days Mustard, tobacco, cotton v) Very long duration crops: above 150 days Sugarcane, redgram, castor. j) According to the method of harvesting i) Reaping : Rice, wheat, ii) Uprooting by pulling : Bengal gram, black gram, lentil, rapeseed iii) Uprooting by digging : Potato, sweet potato, groundnut, carrot etc. iv) Picking : Cotton, vegetables, brinjal, bhendi, chillies v) Priming : Tobacco vi) Cutting : Berseem, napier, amaranthus vii) Grazing : Stylosanthes. k) According to post harvest requirement i) Curing : Tobacco, mustard ii) Stripping : Jute, sunnhemp iii) Shelling : Groundnut iv) Ginning : Cotton v) Seasoning : Turmeric, chillies vi) Grading and sorting : Potato, rice, wheat, fibre crops etc. l) Based on climatic condition 1) Tropical crop : Coconut, sugarcane 2) Sub-tropical crop : Rice, cotton 3) Temperate crop : Wheat, barley 4) Polar crop : All pines, pasture grasses 8. According to important uses: Though plants are useful in many ways only certain uses are given below. i. Catch crops / contingent crops: are those crops cultivated to catch the forth coming season. It replaces the main crop that has failed due to biotic or climatic or management hazards. Generally, they are of very short duration, quick growing, harvestable or usable at any time of their field duration and adaptable to the season, soil and management practices. Eg. Greengram, Blackgram, Cowpea, Onion, Coriander, Bajra. ii. Restorative crops: are those crops which enrich or restore soil fertility or amelioration of the soils. They fix atmospheric nitrogen in root nodules, shed their leaves during ripening and thus restore soil conditions. Eg. Legumes. iii. Exhaustive crops: are those crop plants which on growing leave the field exhausted because of a more aggressive nature. Eg. Gingelly, Maize, sunflower etc. iv. Paira crop / residual crops: are those crop plants which are sown a few days or weeks before the harvest of the standing mature crops to utilize the residual moisture, without preparatory tillage. The standing crop and the later sown (paira) crop become simultaneous (forming a pair) for a short period. For example Black gram in Paddy v. Smother crops: are those crop plants which are able to smother or suppress the weed growth by providing suffocation (curtailing movement of air) and obscuration (of the incidental radiation) Eg. Cowpea vi. Cover crops: are those crop plants which are able to protect the soil surface from erosion (wind, water or both) through their ground covering foliage and or root mats. Example – groundnut, blackgram, marvel grass, sweet potato. vii. Nurse crops: A companion crop which nourishes the main crop by way of nitrogen fixation and or adding the organic matter into the soil. Example-cowpea intercropped with cereals, glyricidia in tea. viii. Guard / barrier crops: are those crop plants which help to protect another crop from trespassing or restrict the speed of wind and thus prevent crop damage. Main crop in the centre surrounded by hardy or thorny crop. Eg. Mesta around sugarcane; sorghum around cotton; safflower around gram. ix. Trap crops: are those crop plants grown to trap soil borne harmful parasitic weeds. Eg. orobanche and striga are trapped by solanaceous and sorghum crops respectively. Nematodes are trapped by solanaceous crops (On uprooting crop plants, nemathodes are removed from the soil). Castor in cotton. x. Mulch crop: To conserve soil moisture, such crops are grown eg: Cowpea xi. Cash crop: Such crops are grown for sale to earn the hard cash eg: Jute, Cotton, Tobacco, Sugarcane xii. Warehouse crops: Such crops are grown for temporary storing as intact in warehouse for future use or sale eg: Potato xiii. Truck crop: Grown to market fresh eg: Behndi, Spinach xiv. Cole crops: Cole is derived from colewart. Colewart is the ancestor of wild cabbage. Therefore, cole crops are essentially cold weather crops belonging to the cruciferae capable of withstanding considerable frost eg: cabbage, cauliflower and Brussles sprouts xv. Augmenting crops: are those sub crops sown to supplement the yield of the main crop. Example – Mustard or cabbage with berseem to augument the forage yield of berseem. xvi. Green manure crops: grown & incorporated freshly in to the soil to increase soil fertility. It may be (a) Green leaf manuring – Calotrophis, (b) Green manuring Insitu – Sunhemp xvii. Silage crop: These are grown to preserve in pits in a succulent condition by a process of natural fermentation or acidification for feeding livestock during lean months Eg. Maize, sorghum, Cowpea xviii. Soilage crop: these are grown to harvest while they are still green and fed fresh to livestock Eg. Cowpea, Napier, Horsegram. MANURES AND FERTILIZERS Plant require certain element for their growth and development. There are about 60 chemical elements present in the plant and it doesn’t mean that all are essential for normal growth and development. Arnon and Stout (1939) proposed criterion of essentiality. Which were refined by Arnon (1954) and are popularly known as Arnon’s criteria of essentiality? They are 1. The deficiency of elements makes it impossible for the plant to complete the vegetative or reproductive stage of its life. 2. The deficiency of elements in question can be corrected only by supplying that particular element 3. The element is directly involved in nutrition and metabolism of the plant quite apart from its possible effect in correcting some micro-biological or chemical conditions in the soil. Based on the above criterion, 16 elements are considered essential for plant growth and development. They are classified as I. Based on quantity of nutrient present in plants, they are grouped into Essential nutrient Basic nutrients Macro nutrients Micro / trace elements C, H, O Fe, Zn, Cu, B, Mo, Mn, Cl Major / Primary nutrient Secondary nutrient N, P, K Ca, Mg, S Basic nutrients : contribute 96% of the total dry matter of plants and are taken in the form of water and air (CO2) Macro nutrients : are required in large quantity (> 1 ppm) and are further divided into a) Major / Primary nutrients : are required in bulk and applied externally Eg. N, P, K. b) Secondary nutrients : They are called secondary because they applied inadvertently to the soil while applying N, P, K fertilizers Eg. Ca, Mg, S. Micro nutrients : Theya re also called trace elements and are required in minute quantity ( 0.75 2. Available Nitrogen (Kg ha-1) < 280 280 – 560 > 560 3. Available P2O5 (Kg ha-1) < 10 10 – 22.5 > 22.5 4. Available K2O (Kg ha-1) < 108 108 – 280 > 280 If the soil are medium fertile, apply recommended dosage. If they are high, apply 25% lower than recommended dose and if they are low, apply 25% extra dose. c) Management : If the farm is managed intensively without any limits for other factors, the optimum dosage boost the yield. If there are limitations for any factor viz, light, water, temperature etc, the higher dosage is uneconomical. Calculation of fertilizer dosage : Fertilizer recommendations are made in elemental or oxidized form of nutrient but not as such as fertilizers available. The amount of fertilizer to be applied can be calculated using the formulae Recommended dosage (Kg ha- Amount of fertilizer 1 ) to be applied (Kg ha- = X 100 1 ) Nutrient content of fertilizer (%) Problem : Calculate the quantity of Urea, SSP, MOP required for paddy crop in 1 ha area with the recommendation of 100:50:50. Solution : Data given - Recommended dosage : 100:50:50 Fertilizers – Urea (46% N), SSP (16% P2O5) and MOP (60% K2O) Calculation of Urea : Recommended dosage (Kg ha- Amount of Urea 1 ) = X 100 required (Kg ha-1) Nutrient content of Urea (%) 100 = X 100 46 = 217.39 Kg ha-1 Calculation of SSP : Recommended dosage (Kg ha- Amount of SSP 1 ) = X 100 required (Kg ha-1) Nutrient content of SSP (%) 50 = X 100 16 = 312.50 Kg ha-1 Calculation of MOP : Recommended dosage (Kg ha- Amount of MOP 1 ) = X 100 required (Kg ha-1) Nutrient content of MOP (%) 50 = X 100 60 = 83.33 Kg ha-1 In situation of deviation in area the formulae can be modified as Area (ha) X Recommended dosage (Kg Amount of fertilizer ha-1) = X 100 to be applied Nutrient content of fertilizer (%) Methods of fertilizer application: Appropriate method of fertilizer application is essential for a) make the nutrients easily available for crop plant b) Reduce fertilizer / nutrient loss c) Ease of application Suitable method for a particular situation depends on the nature of soil, crop and fertilizer material i) Nature of soil : Soil properties like texture, pH, CEC, nutrient and moisture status are important factors to be considered in selecting suitable method. If pH of soil is higher (>8), the ammonia volatilizes and it is not advisable to apply to apply ammonical fertilizer their. If the soil P content is less, P fertilizers as to be applied as band placement to reduce the fixation problems. ii) Nature of crop: It depends on the root system and spacing. If the crop is closely spaced with shallow fibrous roots, fertilizer has to be applied in surface layer through broadcasting followed with irrigation. For widely spaced and deep rooted crop, deep point / band placement is advantageous. iii) Nature of fertilizer: Fertilizer properties like form, solubility, mobility in soil decides the method of application. Granular / powder form can be broadcasted, pellets can be point placed and liquid form can be fertigated. Different methods of fertilizer application: Fertilizer may be applied either in solid or liquid form to the soil. The different methods of soil application of fertilizers are: 1. Application of fertilizers in solid form a. Broadcast: The fertilizers is spread uniformly over the entire surface and then mixed with soil by tillage implements. Broadcasting of fertilizer is done at planting and as top- dressing. b. Placement: Fertilizers are placed in the soil irrespective of the position of seed, seedling or growing plants before sowing or after sowing the crops. i) Plough sole placement: Fertilizer is placed in a continuous band on the bottom of the furrow during ploughing. Each furrow covered as the next furrow is turned. ii) Deep placement of fertilizers: Ammonia forming nitrogenous fertilizer are placed deep in the reduction zone in paddy fields to avoid losses. Deep placement of phosphatic fertilizers in deep black soils for paddy also increases its efficiency. c. Localized placement: Fertilizer is applied into soil close to seed or plant. i) Contact placements or combined drilling or drill placement Only small quantity of fertilizer and seeds combined and drilled so that germination may not be adversely affected. ii) Band placement: Fertilizer is placed in Bands. These bands may be continuous or discontinuous (close to the seed or transplanted plant). Hill placement or ring placement can be followed when plants are widely spaced particularly in square planting. Row placement can be followed for placing fertilizers one side or both sides of the row by hand or a seed drill. iii) Pellet application: Nitrogenous fertilizer is applied in the form of pellets 3-5cm deep between the rows of the paddy crop. The fertilizer is mixed with the soil in the ratio of 1:10 and made into a dough. Small pellets of convenient size are then made and deposited in the soft mud of paddy fields. Application of urea through mud balls and paper packet is convenient for deep placement. 2. Application of liquid fertilizers: a. Starter solutions : Solutions of fertilizers generally consisting of N-P2O5-K2O in the ratio of 1:2:1 and 1:1:2 are applied to young vegetable plants at the time of transplanting, in place of watering. b. Foliar application: This refers to the application of dilute solutions of fertilizers like urea (1-5%) directly on the foliage. Higher concentrations may cause scorching of leaves. When applied along with other spraying operations of pesticides it is less costly. c. Direct application to soil : With the help of special equipment anhydrous ammonia (a liquid high pressure upto 200 pounds per square inch or more) and nitrogen solutions are directly applied to the soil. This practice is very popular in USA. d. Application through irrigation water (fertigation): Straight and mixed fertilizers easily soluble in water are allowed to dissolve in the irrigation stream. The flow of water is regulated based on the dosage. Fertilizer specially secondary & micro-nutrients are also applied to the plant as a) Root dipping: The roots of the seedlings are dipped in nutrient solution before transplanting. b) Foliar spray: fertilizers solutions are sprayed on the foliage of standing crop. Time of Application: The time of fertilizer aimed at providing nutrient in sufficient quantities to meet the crop demand and avoiding excessive availability (toxicity) at all the stages and reducing losses. The time of application depends on crop uptake pattern, soil properties, nature of fertilizer material and utilization of carbohydrates. 1. Crop uptake: NPK are taken by the crop in large quantities in early stage in cereals. Legumes require nitrogen until root nodulation and P & K gradually throughout the crop growth. Further, duration and nature of crop also influence the time greatly. 2. Soil properties: Solubility and availability of nutrients depends on soil physical and chemical properties. In light textured soils, N fertilizer has to be applied in more number of splits. 3. Nature of fertilizers: ‘N’ fertilizer is soluble and highly mobile while, ‘P’ is subjected for fixation problem and become immobile. N fertilizer has to be applied in split dose while, P & K as basal dose. 4. Utilization of carbohydrates: The level of carbohydrates and nitrogen are inversely related. When large quantity of N fertilizer applied, the carbohydrate content reduces. The time of N application depends on the end product. In fodder crops, succulent leaves with higher protein are preferred. Hence, application of N in several splits are essential. N shouldn’t be applied in late stage where the end product is carbohydrates. In Sugarcane, sugar recovery reduces with increased N. Time of fertilizer application can be divided into a) Basal application: Application of fertilizer before or at the time of sowing is known as basal application. A portion of the recommended dose of N and entire dose of P & K are applied as basal in most of the crops. b) Split application: Application of recommended dose of fertilizer in two or three splits during the crop period is known as split application. Application of fertilizer in standing crop is known as Top dressing. Balanced fertilization: refers to the application of NPK nutrients to soil in quantities to bring the balance in nutrients to meet the requirement of any a specific crop. Integrated Nutrient Management (INM) : Plant nutrients can be supplied through different sources viz., organic manure, crop residues, bio-fertilizers, chemical fertilizers. For efficient utilization of nutrients and to produce crop with less cost, INM is the best approach. INM is the judicious nutrient management system where in the nutrient demand of the crop is supplemented with two or more sources considering the economics / cost. GROWTH AND DEVELOPMENT OF CROP Growth is irreversible increase in size or weight. Growth is an irreversible increase in mass or weight whereas development denotes phasic change. Growth is defined as an irreversible change in the size of a cell, organ or whole organism. Commonly, growth is the increase in the amount of living material (protoplasm) which leads to an increase in cell size and ultimately cell division. Growth occurs only in living cells by metabolic process involved in the synthesis of proteins, nucleic acids, lipids and carbohydrate at the expense of metabolic energy provided by photosynthesis and respiration. Development of plant is the orderly and progressive change from seed germination through juvenility, maturity, flowering and fruiting. Environmental factors may influence developmental times or block particular stage altogether. Growth in plants has various phases which start with activation of the embryo and ends with maturation of the seed. The processes involved in growth are very complex and very vitally influenced by environmental factors which themselves form a complex. Growth of any organism increases in size and also in complexity. The quantitative increase in matter is accompanied by changes in nature of their plant parts which are of qualitative character. These phases run their courses during the life cycle of the plant with modifications engendered by the environment. Germination Biochemical Process Morphological Process Germination: Germination is defined as the emergence and development from seed embryo of those essential structures which are indicative of seeds capacity to produce the normal plant under favourable conditions by Justice 1972. As fertilization initiates the transformation of ovule into fertilized seed. So Germination refers to the process by which an organism grows from a seed. The most common forms of germination include a seed sprouting to form a seedling Thus, germination occurs primarily in plant. Three changes or steps occurring during seed germination are: (1) Imbibition (2) Enymatic Activity: (3) Cell enlargement and division Imbibition: The first step in the seed germination is imbibition i.e. absorption of water by the dry seed. Imbibition results in swelling of the seed as the cellular constituents get rehydrated. The swelling takes place with a great force. It ruptures the seed coats and enables the radicle to come out in the form of primary root. Enymatic Activity: The water activates special proteins, called enzymes, that begin the process of seed growth. First the seed grows a root to access water underground. Next, the shoots, or growth above ground, begin to appear. The seed sends a shoot towards the surface, where it will grow leaves to harvest energy from the sun. The leaves continue to grow towards the light source in a process called photo morphogenesis. Cell enlargement and division: Resulting in emergence of radical and plumule. Seeds when sown in moist soil, germinate under favourable temperature and sufficient aeration. Seeds of some plants species do not germinate even under favourable conditions and these seeds of are said to be dormant. In simpler terms, seed dormancy is blocking the growth of embryo. The period of dormancy may be for a few days, weeks, or months. Dormancy may be due to several reasons; improper development of embryo, high concentration of growth inhibiting substances, hard and impermeable seed coat. Seed dormancy in crops is less significant, as dormancy is for a very short period or is broken during the period between harvesting and next sowing. However, it is important with seeds are grouped as 1. Positive photoblasttic, those that require light for inducing germination (lettuce, tobacco, mistletoe, etc.) 2. Negative photoblastic, those that do not germinate when exposed to light (onion, lily, Amaranthus, Nigella, etc.) 3. Non-photoblastic, those that germinate either in light or dark. Seeds of many cultivated crops belong to non-photoblastic group. Flowering plants can be broadly grouped into monocotyledons and dicotyledons. Monocotyledons have single cotyledon in their seeds. Cereals and millets belong to this group. The important parts of monocotyledon seed are embryo, endosperm and aloeurone layer. (FIG). Carbohydrates are stored in endosperm whereas embryo contains miniature root and shoot. In other words, seed is more or less partially formed plant enclosed in protective casing with a reserve of essential food. Under appropriate conditions, this plant has the ability to utilize these reserves and develop into an autotrophic plant. In dicotyledonous plants, the seed contains two cotyledons which provide food material during the process of germination. Biochemical Process: Germination can be grouped into biochemical and morphological processes. When the seed is sown into most soil, it absorbs water twice its weight. As a result, the seed bulges and breaks the seed coat. Subsequently, embryo secretes gibberellins which in turn induces the secretion of hydrolytic enzymes by aleurone layer in cereals. Hydroloytic enzymes break down complex food materials like starches and proteins into simple sugars and amino acids respectively. Fats which occur chiefly in the cotyledons of certain oil bearing seeds and in the embryos of cereal seeds are split by enzymes called lipages into fatty acids and glycerol. These in turn undergo chemical changes and form sugars. The simpler products thus formed are soluble and can be translocated to growing point until the plant becomes autotrophic. The energy required for the chemical and biological process of germination and growth is supplied by respiration. During this process, 25 to 50 per cent of stored food is used up in respiration. Morphological Process: The radical is the first organ to emerge from the seed in nearly all cases. The radical is soon followed by the plumule of uyoung shoot. In many dicotyledonous plants, such as groundnut, beans etc. the cotyledons emerge from the soil and function as first leaves. These first leaves are brought to soil surface without damage because they are present inside the thick cotyledons. The cotyledons are brought out of the soil by curved elongation of hypocotyls. This type of germination where cotyledons emerge out of the soil is called epigeal germination (Fig.) In monocotyledonous plants, the cotyledon remains in the soil. The plumule grows or is pushed upward by the elongation of epicotyls. This type of germination is called hypogeal germination since the cotyledon is below or inside the soil (Fig.). Dicotyledons also exhibit hypogeal germination when sown deep. For example, groundnut when sown deep , the reserves in cotyledons are spent for the elongation of hypocotyls, and only ture leaves come out of the soil. The coleoptiles of grasses emerges from the soil as pale tube like structure that encloses the first true leaf. A slit develops seminal roots. Seminal roots emerge utilizing seed reserves. The average number of root primodia in the embryo shows general variation and they are 4-6 in wheat and about 9 in barley. The number actually developing varies widely and depends on nutrient and water availability. Development: Growth is an irreversible increase in mass or weight whereas development denotes phasic change. The development of a plant from germination to maturity can be considered as a series of discrete periods, each identified by an accompanying process of change in the structure, size or weight of specific organs. Developmental processes relate to relate to varying degrees of expansion or growth in weight of an organ. Some, such as leaf initiation, are associated with only very small changes in size or weight; others such as flowering in millets which follows expansion of the stem and panicle, can only proceed after considerable increase in size and weight. A characteristic of developmental processes is that they are discrete. Seed either germinates or does not germinate; and a leaf primordium is invisible or visible. Therefore, they can only be defined in terms of time, and not in length, area, volume or weight. The duration of a developmental process is usually measured between events that are detected visually. Such durations are those between wetting a seed and the subsequent elongation of the radical to a defined length and between fertilization of flower and the maximum weight of grain or pod. The rate of development is simply the reciprocal of this duration. Developmental Stages: Age of the crop is expressed as crop growth stages. However, the term growth stages are misleading as these stages do not indicate increase in dry weight or mass. They can be called as developmental stages as they indicate age or progress towards maturity. Stage refers to a specific morphological event whereas phase refers to time period between two distinct stage during which a process occurs. The life cycle of a crop is divided into different stages based on morphological characters, developmental stages etc. the demarcation of crop into different developmental stages helps in better communication among farmers, extension workers and scientists. The expression of crop age or stage by calendar days is misleading because the duration of certain physiological stages are altered by climate. Panicle initiation in cereals, which is an important stage for application of fertilizers and irrigation, may be delayed or advanced by photoperiod and temperature. In rice, low temperarure delays panicle initiation. The developmental stages are helpful in identifying the time for scheduling irrigation, application of fertilizers, herbicides etc. certain stages of crop growth are very sensitive to moisture stress. For example, moisture stress at crown root initiation stage reduces the grain yield of wheat considerably and it cannot be compensated by subsequent better management practices. Fertilizer application is made in split doses to avoid leaching losses but sufficient quanties are to be applied each time to meet the crop demand. As nutrient requirement at panicle initiation stage is high sufficient dose is applied at this stage. Similarly, for effective control of weeds and to reduce adverse effect of herbicides on crop, they have to be applied at proper stage of the crop. The crop developmental Stages applicable to most of the crops are: germination, emergence, seedling stage, maximum vegetative growth stage, primordial differentiation, flowering, fruit growth, fruit maturity, physiological maturity and harvest maturity. These crop stages are named differently to suit the peculiarities of individual crops. Germination and Emergence: after sowing of the crop, the seeds absorb moisture and put forth radical and plumule and it is known as germination. On subsequent growth, the plumule is pushed through the soil and comes out of soil and this is known as emergence. Seedling Stage: subsequent to emergence, the plants put forth leaves and no longer depend on seed reserves. During this stage, the plants establish by developing sufficient number of seminal roots and leaves. This stage ends when the plants put forth tillers or branches. Maximum vegetative Growth stage: During this stage, crops grow at a faster rate. Plants start producing branches or tillers and the crop covers the ground, as much as possible, to intercept more radiation. The loss of plant population that occurs during early stages can be overcome in this stage by producing more number of tillers or branches. The number of ears per unit area are decided during this stage. This stage is variously called as tillering stage, active tillering stage, branching stage etc. depending on the crop. Primordial differentiation stage: this stage is called as panicle initiation stage in cereals and millets, squaring in cotton, flower bud initiation in sunflower etc. with starting of this stage, plants enter reproductive phase. The number of fruits or grains are decided during this stage. This stage is more sensitive to moisture and solar radiation. Flowering stage: this stage is also called as 50 per cent flowering, anthesis, blooming etc. the crop is said to be at 50 per cent flowering when 50 per cent of plants put forth flowers. Opening of flowers and shedding of pollen is called anthesis. Blooming also indicates opening of flowers. This stage is very sensitive to moisture stress. Fruit set is development of flowers into fruits and this is a very important stage. Fruit Growth Stage: During this stage, photosynthates are accumulated in the fruits. Fruit growth is also called as grain growth in cereals, pod growth in groundnut and pulses, boll growth in cotton etc. Maturity Stage: During this stage, biochemical reaction takes place in the fruits for the sysnthesis of proteins, oils and starches from simple carbohydrates. These complex products are synthesized in fruit itself or synthesized in leaves and transl

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