Agricultural Crop And Soil Science PDF

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AGRICULTURAL AND BIOSYSTEMES ENGINEERING AGRICULTURAL CROP AND SOIL SCIENCE Chapter - 1 INTRODUCTION TO AGRICULTURE AND CROP PRODUCTION Meaning and definition of Agriculture ▪ The word agriculture comes from the Latin words ager, means the soil & cultura, means cultivation, when combined, the Latin agricultura, means field or land tillage ▪ Agriculture can be defined as the science, art, or practice of cultivating the soil, producing crops, and raising livestock and in varying degrees the preparation and marketing of the resulting products ▪ But the word has come to subsume a very wide spectrum of activities that are integral to agriculture and have their own descriptive terms, such as cultivation, domestication, horticulture, arboriculture, and vegeculture, as well as forms of livestock management such as mixed crop-livestock farming, pastoralism, and transhumance. Scope of Agriculture 1. National Economy: It is the backbone of national economy because it contributes a major portion of national income. 2. Employment generation: Majority of population is working & depends on agriculture and allied activities. 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. 3. 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. 4. Food Supply: It plays an important role in feeding the growing population. 5. National Revenue: The agriculture is contributing the revenue by agriculture taxation includes direct tax and indirect tax. Direct tax includes land revenue, and surcharge on land revenue, on crops & agril. Income tax. Indirect tax induces sales tax, custom duty and which farmer pays on purchase of agriculture inputs. 6. Trade: Agriculture plays an important role in foreign trade attracting valuable foreign exchange, necessary for our economic development. Philippine agriculture also plays an important role in roads, rails & waterways outside the countries. Philippine roads, rails and waterways used to transport considerable amount of agricultural produce and agro based industrial products. Crop production It is one of the agricultural sciences, which plays a key role in enhancing the total production by improving productivity resulting in food security. ▪ It teaches us what crops should be cultivated in a particular climate and in each kind of soil and what water management practices are to be followed in order to realize the higher productivity. ▪ It is basically conversion of environmental inputs (solar energy, CO2, water, soil nutrients) into economic products in the form of human or animal food or industrial raw material.  Page 2 of 28 ▪ Principles and practices are the two important aspects of crop production. ▪ For growing a good crop, one should know the important principles of the crop production plants or livestock products‟  Page 3 of 28 Chapter – 2 CLASSIFICATION OF CROPS Range of cultivation a. Garden crops: They are grown on a small scale in gardens. e.g., onion, brinjal, etc. b. Plantation crops: They are grown on a large scale in estates and perennial in nature. e.g., tea, coffee, cacao, rubber etc. c. Field crops: They are grown on a vast scale under field condition. They are mostly seasonal such as rice, wheat, cotton etc. Place of origin a. Native crops: They are grown within the geographical limits of their origin, e.g., rice, barely, blackgram, green gram, mustard, castor, sugarcane and cotton, grown in India, are native to India. b. Exotic or Introduced crops: They are introduced from other countries, such as tobacco, potato, jute, maize, apple, etc. Botanical/taxonomical classification According to systematic botany, plants are classified as order, family etc. Similarly crop plants are grouped into families as: a. Poaceae (Graminae): Cereals, millets and grasses b. Papilionaceae (Legumes):Pulses, legume fodders, vegetables, groundnut, berseem, green manures etc. c. Cruciferae: Mustard, Indian rape seed, radish cabbage, cauliflower etc. d. Cucurbitaceae: All gourds, cucumber, pumpkin etc. e. Malvaceae: Cotton, lady‟s finger, roselle etc. f. Solanaceae: Potato, tomato, tobacco, chillies, brinjal g. Tiliaceae: Jute h. Asteraceae (Compositae): Sunflower, safflower, niger i. Chenopodiaceae: Spinach, sugar beet j. Pedeliaceae: Sesame k. Euphorbiaceae: Castor, tapioca l. Convolvulaceae: Sweet potato m. Umbelliferae: Coriander, cumin, carrot, anise n. Liliaceae: Onion, garlic o. Zingiberaceae: Ginger, turmeric Commercial classification Based on the plant products which come into the commercial field are grouped as: a) Food crops: Rice, wheat, green gram, soybean, groundnut, etc. b) Food crops/Forage crops: All fodders, oats, sorghum, maize, napier grass, Lucerne etc. c) Industrial/Commercial crops: Cotton, sugarcane, sugar beet, tobacco, jute, etc. d) Food adjuvunts: Turmeric, garlic, cumin, etc. Economic/Agrarian/Agricultural/Agronomical classification This classification is based on use of crop plants and their products. This is an important classification as for as agronomy is concerned. 1. Cereals ▪ They are cultivated grasses grown for their edible starchy grains (one seeded fruit– caryopsis). ▪ Their larger grains are used as staple food e.g. rice, wheat, maize, barley, etc. ▪ The word cereal was derived from the word ceres, which denotes a goddess who was believed as the giver of grains by Romans. 2. Millets ▪ Small grained cereals, which form the staple food in drier regions of the developing countries, are called millets. e.g. major- sorghum, pearl millet or cumbu and finger millet or ragi. Minor- fox-tail millet, little millet, common millet, barnyard millet and kodomillet 3. Oil seeds: They yield seeds rich in fatty acids, are used to extract vegetable oils.e.g. groundnut or peanut, sesame or gingelly, sunflower, castor, linseed or flax, niger, safflower, mustard and cotton. 4. Pulses: Seeds of leguminous plants used as food. They produce dal rich in protein. e.g., red gram, black gram, green gram, cowpea, Bengal gram, horse gram, dew gram, soybean, peas or garden pea and garden-bean. 5. Feed/Forage: It refers to vegetative matter, fresh or preserved, utilized as feed for animals. It includes hay, silage, pasturage and fodder. e.g., bajra napier grass, guinea grass, fodder-sorghum, fodder-maize, lucerne, desmanthus, etc. 6. Fibre crops: Plants are grown for their fibre yield. There are different kinds of fibre. They are: seed fibre–cotton, (ii) stem  Page 4 of 28 fibre-jute, mesta, (iii) leaf fibre–agave, pineapple. 7. Sugar and starch crops: They are grown for production of sugar and starch. e.g., sugarcane, sugar beet, potato, sweet potato, tapioca and asparagus. 8. Spices and condiments: Crop plants or their products are used to flavour, taste, and add colour to the fresh or preserved food. e.g., ginger, garlic, fenugreek, cumin, turmeric, chillies, onion, coriander, anise and asafetida. 9. Drug crops/medicinal plants: They are used for preparation of medicines. e.g., tobacco, mint etc. 10. Narcotics, fumitories and masticatories: Plants/products are used for stimulating, numbing, drowsing or relishing effects. e.g., tobacco, ganja, opium poppy. 11. Beverages: Products of crops are used for preparation of mild, agreeable and stimulating drinking. e.g., tea, coffee, cocoa. According to ontogeny It is a classification based on the life cycle of a plant. 1. Annual crops ▪ Crop plants that complete life cycle within a season or year. ▪ They produce seed and die within the season. e.g., wheat, rice, maize, mustard. 2. Biennial crops ▪ Plants that have life span of two consecutive seasons or years. ▪ First year/Season these plants have purely vegetative growth usually confined to rosette of leaves. ▪ The tap root is often fleshy and serves as a food storage organ. ▪ During the second year/season, they produce flower stocks from the crown and after producing seeds the plants die. e.g., sugar beet, beet root, cabbage, radish, carrot, etc. 3. Perennial crops ▪ They live for three or more years. ▪ They may be seed bearing or non-seed bearing. e.g., sugarcane, napier grass. ▪ In general perennial crops occupy land for more than 30 months. According to cultural requirement of crops 1. Crops grown on upland: They are grown on upland leveled elevated land with drain all around or unbunded leveled land with drains or drops. Crops that cannot tolerant water stagnation come under this group. e.g., red gram, groundnut, maize, sorghum, cotton, sesame, napier etc. Crops that require sufficient soil moisture but cannot tolerate water stagnation. e.g., potato, sugarcane, upland rice, ragi, wheat, black gram, Bengal gram. 2. Crops grown on lowland: They are grown on lowlands provided with dykes or bunds all around to stagnate water. Crops that require abundant supply of water and can withstand prolonged water logged conditions. e.g., rice, daintier, paragrass and jute. According to source of water 1. Irrigated crops: The crop cultivation primarily depends upon the irrigation water for a part/entire growth period of the crop. All crops irrespective seasons are possible to be raised in this category. 2. Rainfed crops: The crop cultivation entirely depends upon the rainfall received. Crop varieties depend upon the season and the rainfall pattern. According to the depth of root system 1. Shallow rooted crops: Rice, potato, and onion 2. Moderately deep rooted: Wheat, groundnut, castor and tobacco 3. Deep rooted: Maize, cotton, and sorghum 4. Very deep rooted: Sugarcane, safflower According to method of sowing/planting 1. Direct seeded crop: Where the seeds are sown directly either dry or sprouted. e.g. upland rice, wheat, jowar, bajra, groundnut etc. 2. Planted crops: Where plant parts are planted directly. e.g., sugarcane, potato, sweet potato, napier, guinea grass. 3. Transplanted crops: Where seedlings are raised in the nursery, pulled out and planted in the field. e.g. rice, ragi, bajra, tobacco, bellary onion, brinjal  Page 5 of 28 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 According to important uses 1. Catch crops/contingent crops ▪ These crops are 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. They provide feed, check weed growth, conserve soil, utilized added fertilizer and moisture. e.g., green gram, black gram, cowpea, onion, coriander and bajra. 2. Cover crops ▪ These 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. e.g., groundnut, black gram, marvel grass, sweet potato 3. Trap crops ▪ These crop plants are grown to trap soil borne harmful parasitic weeds. For e.g., orabanche and striga are trapped by solanaceous and sorghum crops, respectively. ▪ Nematodes are trapped by solanaceous crops (on uprooting crop plants, nematodes are removed from the soil). ▪ Castor in cotton, groundnut act as crop for army worm pest. 4. Alley crops ▪ These arable crops are grown in „alleys‟ formed by trees or shrubs, established mainly to hasten soil fertility restoration, enhance soil productivity and reduce soil erosion. ▪ They are generally of non-trailing with shade tolerance capacity. For e.g., growing pulses in between the rows of casuarina. Chapter - 3 ESSENTIAL NUTRIENT ELEMENTS FOR CROP GROWTH Essential nutrient elements play an important role in improving growth and development of crops resulting in higher crop production. Classification of nutrient elements The essential elements can be classified based on the amount required, their mobility in plant and soil, their chemical nature and their functions in the plant. On the basis of the required amount of nutrients: Twenty elements have been demonstrated to be essential for plant growth. These elements have been classified into two groups on the basis of the required amount by the crop plants. Macro/major element: It is required in relatively large amount Micro/minor/trace element: It is required in relatively small amounts On the basis of mobility in soil - -2 -2 - ++ 1. Mobile nutrients: They are highly soluble and are not adsorbed on clay complex: e.g. NO3 , SO4 , BO3 , Cl , and Mn. + 2. Less mobile nutrients: They are also soluble, but they are adsorbed on clay complex and so their mobility is reduced. e.g. NH4 , + ++ ++ ++ K , Ca , Mg , Cu. - - Immobile nutrients: Ions are highly reactive and get fixed in the soil. H2SO4 , HPO4 - ++ , Zn. On the basis of mobility in plant. Knowledge of the mobility of nutrients in plants help in finding what nutrient is deficient. A mobile nutrient in plant, move the growing points in case of efficiency. Deficiency symptoms therefore appear on the lower leaves.  Page 6 of 28 Mobile: N, P and K Moderately mobile: Zn Less mobile: S, Fe, Mn, Mo and Cl Immobile: Ca and B On the basis of chemical nature Nutrients can be classified in to cations and anions and metals and non-metals based on their chemical mature. Cations: K, Ca, Mg, Fe, Mn, Zn, and Cu - Anions: NO3 ,H2PO4,SO4 Metals: K, Ca, Mg, Fe, Mn, Zn, and Cu Nonmetals: N, P, S, MO, Cl Macro- and micro- nutrient elements Primary Secondary Iron (Fe) Carbon (C) Nitrogen (N) Calcium (Ca) Manganese (Mn) Hydrogen (H) Phosphorus (P) Magnesium (Mg) Boron (B) Oxygen (O) Potassium (K) Sulphur (S) Molybdenum (Mo) Copper (Cu) Zinc (Zn) Chloride (Cl) Cobalt (Co) Functional elements (Nicholas, 1961) Sodium (Na) Vanadium (V) Silicon (Si) Plants absorb elements in ionic and non ionic forms. Ionic and non ionic forms for different nutrient elements have been given in table 3.2. Ionic and non ionic forms of nutrient elements Element Ionic Non ionic Macronutrient elements Nitrogen (N) + - 2 NH4 , NO3 CO(NH2) Phosphorus (P) - 2- Nucleic acid, Phytin H2PO4 , HPO4 Potassium (K) + K Calcium (Ca) 2+ Ca Magnesium (Mg) 2+ Mg Sulphur (S) 2- SO2 SO4 Micronutrient elements Iron (Fe) 2- 3- Fe SO4 with EDTA Fe ,Fe Manganese (Mn) 2+ MnSO4 Mn EDTA Boron (B) 2- - 2- B4O7 H2BO3 , HBO3 Molybdenum (Mo) 2- MoO4 Copper (Cu) 2+ CuSO4 with EDTA Cu Zinc (Zn) 2+ Zn SO4 with EDTA Zn Chloride (Cl) - Cl Cobalt (Co)  Page 7 of 28 Role of nutrients, deficiency symptoms and control of deficiency Page 8 of 28  Page 9 of 28 Chapter- 4 WEATHER AND SOIL ELEMENTS AND THEIR EFFECT ON CROP GROWTH Crop growth is defined as irreversible increase in size, measured as dry weight, which occurs throughout the crop life cycle. It may be expressed in terms of dry weight, length, height or diameter. Crop development is the progression through the morphological changes, which occur during growth of the crop. It is more readily described qualitatively than quantitatively. For example, development of a crop plant from germination to maturity. Weather elements i. Air temperature ii. Solar radiation iii. Precipitation iv. Wind v. Composition of the atmosphere Effect of weather elements on crop growth i. Air temperature: It is a measure of intensity of heat. Temperature required for the growth is ranging from 5 to 45 0C. It directly influences photosynthesis, respiration, cell wall permeability, nutrient and water absorption, transpiration, enzyme activity and protein coagulation.  Page 10 of 28 ii. Solar Radiation: This is the radiant energy from the sun, measured as a total amount (direct solar plus sky radiation) expressed - in cal cm-2 min-1 measured by pyrheliometer. For photosynthesis, only visible part of the total solar energy is of importance. Photosynthesis in green leaves use solar energy in wavelengths from 0.4to 0.7 m often referred to as photosynthetically active radiation (PAR) or simply light. Radiant energy influences the protoplasm permeability, intake and loss of water, enzyme activity, respiration, photosynthesis, flower initiation and ripening of fruits. Three aspects of light-intensity (quantity), duration (day length) and quality (spectral distribution). iii. Precipitation: The essential requirement of water for plant growth can be visualized from the fact that it may constitute 70-95% of total fresh weight when it is actively growing. Precipitation is the major source of soil moisture for crop growth in dry regions during rainy season. A number of physiological processes in crop growth is affected due to water stress. Cell growth, cell wall and protein synthesis are adversely affected by the stress. High humidity can increase the risk of disease and pest outbreak. Consequences of high intensity rains of long duration (floods) on crop production are well established. iv. Wind: Plant responses to wind. Wind over the crop surface can alter the onset of drought during dry periods due to water vapor loss through transpiration. This may lead to stomatal closure and reduce rate of gaseous exchange leading to reduced photosynthesis and crop growth. Strong winds in association with rain can cause lodging, particularly at flowering in cereals. Provision of windbreaks in exposed areas can minimize the adverse effects of high wind speed. Growth of plants, in general, seems to be inhibited at wind speeds above 10kmph. However, there are individual variations. v. Composition of the atmosphere: Certain gases, such as sulphur dioxide (SO2),carbon monoxide (CO) and hydrofluoric acid (HF) when released into air in sufficient quantities are toxic to plants. Acid rain is often due to relatively high concentrations of surphur dioxide and sulphates. Some of the effects that acid rain can have on plants and soil include increased leaching of inorganic nutrients, damage to leaves at pH6 Ca and Mg 7-8.5 Fe 7 Mineral nutrient supply: Capacity of the soil to supply essential plant nutrient elements has profound influence on crop production. Soil analysis provides estimates of the levels of available nutrients for determining the suitability of a soil for a particular crop and in formulating more precisely the fertilizer requirements. The inherent capacity of soil to supply amount of adequate nutrients to plants in balanced form is known as soil fertility while soil productivity is the capacity of soil to yield crops per unit area. Soil fertility differs from soil productivity as under:  Page 13 of 28 Soil fertility Soil productivity It is an index of available nutrients to crop plants It is an indicator of crop yields. It is one of the crop production factors.It is the interaction of all the factors. It can be analyzed in the laboratory. It can be assessed in the field only. It is the potential status of the factors soil to produce crops It is the resultant of various influencing soil management. Chapter-5 TILLAGE Tillage is the important operation in crop production. With good tillage operations, higher yield can be achieved. TJethro Tull is considered as father of tillage. He proposed a theory that „Plants absorb minute particles of soils’. Therefore, he suggested that thorough ploughing and other operations were necessary so as to make soil into fine particles. Though his theory is not absolutely correct, tillage operations are carried out to prepare a fine seedbed for sowing crops. After harvest of the crop, soil becomes hard and compact. Beating action of rain drops, irrigation and subsequent drying, movement of inter-cultivation implements and labor cause soil compaction. Field contains weed and stubbles after the harvest of the crop. Seeds need loose, friable soil with sufficient air and water for good germination. The field should be free from weed and stubbles to avoid competition with crop and to facilitate easy and smooth movement of sowing implements. Definition Tillage is the physical manipulation of the soil with tools and implements for obtaining conditions ideal for seed germination, seedling establishment and growth of crops. The term tilth is used to describe qualitative characteristics of a loose friable (mellow) and crumby conditions of the soil favorable for crop production. In other words, tilth is a physical condition of the soil resulting from tillage. A soil with good tilth is quite porous and has free drainage up to water table. The capillary and non-capillary pores should be in equal proportion so that sufficient amount of water is retained in the soil as well as free air. Objectives The important objectives of tillage for cop production are: To prepare a suitable seedbed 1. To destruct the weeds, insect pests and pathogen To conserve soil and moisture 2. To improve soil physical properties (soil structure, soil aeration, pore space, etc.) To encourage the root penetration 3. To mix the applied manures and fertilizers To remove the hard pan Seedbed preparation: Good seedbed is necessary for early seed germination and initial good stand of the crop. The seedbed should be fine for small seeded crops and moderate for bold seeded crops. Intimate contact between the soil particles is necessary to facilitate movement of water for quicker germination. Destruction of weeds, insect pest and pathogen: Tillage destroys a number of weeds, insect pests and pathogens, which are responsible for poor growth, and development of the crop plants results in poor yield. Soil and moisture conservation: Proper tillage results in soil and moisture conservation through higher infiltration reduced runoff and increased depth of soil for moisture storage. When the compact soil is ploughed, it becomes fluffy and can hold more amount of water. Removal of hard pans, increase the soil depth for water absorption. Soil physical properties: Tillage has considerable influence on soil physical properties like pore space, soil structure, bulk density, water content and colour. Tillage practices have, therefore, greatest effect on seedbed preparation, seedling emergence and stand establishment.  Page 14 of 28 Types of tillage 1. Primary tillage: Ploughing is the opening of the compact soil with the help of different ploughs. Ploughing is done mainly to open the hard soil. In addition, ploughing should ensure inversion (whenever necessary) of soil, uprooting of weeds and stubbles and less cloudy soil surface. 2. Primary tillage implements: The implements, which are used for ploughing, are known as primary tillage implements. Disc plough, mould bold plough are the examples of primary tillage implements. 3. Secondary tillage: Lighter or finer operations performed on the soil after primary tillage are known as secondary tillage. After ploughing, the fields are left with large clods with some weeds and stubbles partially. Harrowing is done to a shallow depth to crush the clods and uproot the remaining weeds and stubbles. Planking is done to crush the hard clods to smoothen the soil surface and to compact the soil lightly. 4. Secondary tillage implements: The implements, which are used for other operations after ploughing, are known as secondary tillage implements. Disc harrows, cultivators, blade harrow etc. are the examples of secondary primary tillage implements Thus, the field is made ready for sowing after ploughing by harrowing and planking. Generally sowing operations are also included in secondary tillage. Modern concepts of tillage In conventional tillage combined primary and secondary tillage operations are performed in preparing seed bed by using animal or tractor, which cause hard pan in sub soils resulting in poor infiltration of rain water, thus it is more susceptible to run off and soil erosion. Farmers usually prepare fine seed bed by repeated ploughing, when the animal of the farm is having less work. Research has shown that frequent tillage is rarely beneficial and often detrimental. Repeated use of heavy machinery destroys structures, causes soil pans and leads to soil erosion. Minimum Tillage Minimum tillage is aimed at reducing tillage to the minimum necessary for ensuring a good seedbed, rapid germination, a satisfactory stand and favorable growing conditions. Tillage can be reduced in two ways by omitting operations, which do not give much benefit when compared to the cost, and by combining agricultural operations like seeding and fertilizer application. Advantages a. Improved soil conditions due to decomposition of plant residues in situ b. Higher infiltration caused by the vegetation present on the soil and channels formed by the decomposition of dead roots c. Less resistance to root growth due to improved structure d. Less soil compaction by the reduced movement of heavy tillage vehicles Less soil erosion compared to conventional tillage Disadvantages a. Seed germination is lower with minimum tillage. b. More nitrogen has to be added as the rate of decomposition of organic matter is slow. This point holds good only in temperate regions. Contrary to this in tropics, minimum tillage recommended to conserve organic matter in the soil. c. Nodulation is affected in some leguminous crops like peas and broad beans. d. Sowing operations are difficult with ordinary equipment. e. Continuous use of herbicides causes pollution problems and dominance of perennial problematic weeds (weed shift). Methods of obtaining minimum tillage a. Row zone tillage: Primary tillage is done with mould board plough in the entire area of the field, secondary tillage operations like discing and harrowing are reduced and done only in row zone. b. Plough plant tillage: After the primary tillage a special planter is used for sowing. In one run over the field, the row zone is pulverized and seeds are sown by the planter. c. Wheel track planting: Primary ploughing is done as usual. Tractor is used for sowing, the wheels of the tractor pulverize the row zone in which planting is done. Zero Tillage/No Tillage/Chemical Tillage ▪ Zero tillage is an extreme form of minimum tillage. ▪ Primary tillage is completely avoided and secondary tillage is restricted to seedbed preparation in the row zone only. ▪ It is also known as no-tillage and is resorted to places where soils are subjected to wind and water erosion, timing of tillage operation is too difficult and requirements of energy and labor for tillage are also too high. ▪ Weeds are controlled using herbicides. ▪ Hence, it is also referred as chemical tillage.  Page 15 of 28 Chapter- 6 MANURES AND FERTILIZERS Soil is the important source of plant nutrients. When the crop requirements are higher than the soil supplying power, nutrients are applied as manures/fertilizers. Manures Manures are plant and animal wastes that are used as sources of plant nutrients. They release nutrients after their decomposition. Classification of manures Manures have been classified into two groups i.e. bulky organic and concentrated organic manures. Bulky organic manures: They contain small percentage of nutrients and are applied in large quantities. FYM, compost, green manure, night soil, sewage and sludge, vermicompost, sheep and goat manures and poultry manures are important examples of bulky organic manures. They are as under: i. Farm yard manure: Decomposed mixture of dung and urine of farm animals plus litter over materials from roughages of fodder fed to the cattle. It contains 0.5, 0.2 and 0.5 % of N, P2O5 and K2O, respectively. ii. Compost: A mass of rotted organic materials made from waste is called compost. It contains 0.5, 0.15 and 0.5 % of N, P2O5 and K2O, respectively. iii. Vermicompost: It is prepared with the help of earthworms. Earthworms consume large quantities of organic matter and excrete soil as caste. It contains 3.0, 1.0 and 1.5 % of N, P2O5 and K2O, respectively. iv. Green manure: Green un-decomposed plant material is known as green manure. v. Night soil: Human excreta, both solid and liquid, are known as night soil. It contains 5.5, 4.0 and 2.0 % of N, P2O5 and K2O, respectively. vi. Sewage and sludge: In the modern system of sanitation adopted in cities/towns, human excreta are flushed out with water, which is called sewage. The solid portion is known as sludge while liquid portion is known as sewage water. vii. Sheep and goat manures: The droppings of sheep and goats contain higher nutrients than FYM and compost. It contains 3.0, 1.0 and 2.0 % of N, P2O5 and K2O, respectively. viii. Poultry manure: The excreta of birds ferment very quickly. It contains 3.03, 2.63 and 1.4 % of N, P2O5 and K2O, respectively. Green manure: Green un-decomposed plant material used as manure is known as green manure. It is obtained by following two ways: ▪ By growing green manure crops ▪ By collecting green leaves from plants grown in wastelands, field bunds and forest Green manuring: Growing of green manure plants, usually belonging to leguminous family, in the field and incorporation into the soil after sufficient growth is known as green manuring. Green manure crops: The plants that are grown for green manure are known as green manure crops. Important green manure crops are: Sesbania aculeate, Crotalaria juncea, Sesbania rostrata, cowpea, clusterbean etc. Advantages of green manuring i. It adds organic matter (OM) and nitrogen (N) in the soil. ii. It facilitates in bringing nutrients to the top layer from deep layers due to growing deep rooted green manure crops and then its incorporation in the soil. iii. It increases nutrient availability due to production of CO2 and organic acids during decomposition. iv. It improves soil structure. v. It increases water holding capacity (WHC). vi. It decreases soil loss by erosion. vii. It reduces weed proliferation and weed growth. viii. It helps in reclamation of alkali soils. ix. It controls root knots nematodes  Page 16 of 28 Fertilizers The chemicals, which are industrially manufactured and contain plant nutrients are known as fertilizers. Nutrient content is higher in fertilizers than in organic manures and nutrients are released immediately just after its application in the soils. Classification of fertilizers According to its manufacturing and primary plant nutrients present in it i. Straight fertilizers: The chemicals which supply only one primary plant nutrient, namely nitrogen or phosphorus or potassium are known as straight fertilizers. Urea (46% N), Ammonium Sulphate (20.5% N, 23.4 % S), Potassium Chloride (58-60% K2O), Potassium Sulphate (48-50% K2O) and Single Super Phosphate (16-22% P2O5) are the examples of straight fertilizers. ii. Complex fertilizers: The chemicals, which supply two or three primary plant nutrients of which two primary nutrients are in chemical combination, are known as complex fertilizers. Theses fertilizers are produced in granular form. Diammonium Phosphate (18% N, 46% P2O5), Nitro-phosphate Suphala (18:18:9; 20:20:2), Ammonium Phosphate (20% P2O5, 20% N), Ammonium phosphate Sulphate (16% N, 20% P2O5) are some of the examples of complex fertilizers. iii. Mixed fertilizers: Physical mixture of straight fertilizers is known as mixed fertilizers. They contain 2 or 3 primary plant nutrients. These are made by thoroughly mixing the ingredients either mechanically or manually. 12:32:16 and 15:15:15 are the examples of mixed fertilizers. According to the concentration of primary plant nutrient i. Low analysis fertilizers: The chemicals, which contain less than 25% of one of the primary nutrients, are known as low analysis fertilizers. SSP (16% P2O5 ), Ammonium Phosphate(20% P2O5, 20% N), and NaNO3(16%N) are some of the examples of low analysis fertilizers. ii. High analysis fertilizers: The chemicals, which contain more than 25% of one of the primary nutrients, are known as high analysis fertilizers. Urea (46% N), Potassium Sulphate (48-50% K2O) and Diammonium Phosphate (18% N, 46% P2O5) are the examples of high analysis fertilizers. According to the physical form of fertilizer i. Solid fertilizers: Most of the fertilizers are in solid form. These are found in several forms like powder (SSP), crystal (AS), pills (urea, DAP, Super phosphate), granules (Holland granules), super-granules (Super granule urea) and briquettes (urea biquettes). ii. Liquid fertilizers: Some of the fertilizers are available in liquid form (Anhydrous Ammonia, 82% N, Urea-Ammonium Nitrate, 28-32% N) for applying either with irrigation water or for direct application. It is of two types, clear liquid fertilizers and suspension liquid fertilizers. iii. Clear liquid fertilizers are those chemicals, which completely dissolve in water whereas suspension liquid fertilizers don’t dissolve completely. Some suspended fine particles are there in the water According to its nutrients present in it i. Nitrogenous fertilizers: The chemicals, which contain only nitrogen element, are known as nitrogenous fertilizers. NaNO3, Ca(NO3)2 , Ammonium Sulphate, Ammonium Chloride, Ammonium Nitrate etc. are the examples of nitrogenous fertilizers. ii. Phosphatic fertilizers: The chemicals, which contain only phosphorus element, are known as phosphatic fertilizers. Water soluble phosphoric acids(SSP, DAP), citric acid soluble phosphoric acid (Basic slag, 14-18 % P2O5, Dicalcium Phosphate, 34- 39 P2O5) and Phosphoric acid not soluble in water and citric acid (Rock phosphate, 20-25% P2O5, Raw bone meal, 20-25% P2O5) are the examples of phosphatic fertilizers. iii. Potassic fertilizers: The chemicals, which contain only potassium element, are known as potassic fertilizers. Potassium Chloride (58-60% K2O), Potassium Sulphate (48-50% K2O) and Potassium Nitrate (13% N, 44% K2O) are the examples of potassic fertilizers. Chloride form, KCl, is not suitable for sugar crops, tobacco and potato while non-chloride form is suitable for these crops. Methods of fertilizer application Fertilizers are applied by different methods to make nutrients available to the crops to reduce fertilizer losses and for easy of application. Methods depend on the nature of the soil, crop and fertilizer material. Pre-planting i. Broadcast (unincorporated and incorporated): In this method, fertilizer is applied uniformly over the field before planting the crop, and it is mixed by tillering or cultivating. Where, there is no opportunity for incorporation (perennial forage and non-till cropping systems), fertilizer may be broadcasted on the surface. ii. Surface band: Surface band applied fertilizers can be an effective method of pre- planting application. However, if not incorporated, dry surface soil conditions can reduce nutrient uptake especially with immobile nutrients. Surface band application of nitrogen can improve nitrogen use efficiency as compared to broadcast application.  Page 17 of 28 iii. Sub-surface band: In this method, fertilizer is placed at the depth of 2 to 8 inch depending on the crop and fertilizer source. For immobile nutrients, sub-surface point or spoke injection) can be effective. Point injection of nitrogen in no- till systems is also more efficient than broadcast N. At planting i. Seed band: Fertilizer application with the seed also is a sub-surface band but it commonly used as starter or pop-up application. These are generally used to enhance early seedling vigor, especially in cold, wet soils. Starter fertilization can also be placed near the seed instead of with the seed. Usually low rates of fertilizer are applied to avoid germination or seedling damage. ii. Surface band: Fertilizer can be surface applied or dibbled at planting in bands directly over the row or several inches to the side of the row. Application over the row can be an effective method of placement of immobile nutrients with a hoe opener because soil can slough off over time and cover up the fertilizer band. Thus, surface applied band becomes a subsurface band placed slightly above the seed. iii. Sub-surface band: In this method, fertilizer is applied 1-2 inch directly below the seed or 1-3 inch to the side and below the seed depending on the equipment and crop. Sub-surface application of liquid sources is more common. After planting i. Broadcast (Top dressing): In this method, fertilizer is broadcasted uniformly in the field having crop plants. Top dressing of nitrogen is common on small grain and pasture, however, top-dressed P & K is not as effective as pre-plant application. ii. Surface band: Fertilizer can also be surface applied or dibbled after planting in bands. iii. Sub-surface band (Side dressing): Side dressing application of N is very common with corn, sorghum, cotton etc. and is done with a standard knife or point injector applicator. Anhydrous NH3 and liquid sources are most common. This method allows a grower more flexibility in application time since side dress application can be made almost anytime. The equipment can be operated without damage to the crop. Sub- surface side dress application with a knife too close to the plant can cause damage by either root pruning or fertilizer toxicity (anhydrous NH3). Side dress application of immobile nutrients is not recommended because most crops need P & K early in the season and during the reproduction growth stage. Chapter-7 SOIL WATER RELATIONSHIP AND CROP WATER REQUIREMENT The soil moisture is the most important component or ingredient of the soil, which plays a vital role in crop production or plant growth. Water is retained as thin film around the soil particles and in the capillary pores by the forces of adhesion, cohesion and surface tension. i. Adhesion: It is the force of attraction between molecules of different substance. That is the force of attraction between solid surface (soil mass) to liquid surface (soil water). A thin film of water is held in soil particles due to this adhesive force. ii. Cohesion: Cohesion is the force of attraction between molecules of same substances i.e., between liquid molecules or water molecules. Hence, a thick film of water is formed due to this cohesive force. iii. Surface Tension: It is the total force acting in a solid-liquid-air system. The liquid surface has some properties of stretched elastic nature. This is due to the unequal forces of molecular attraction at the surface layer. This elasticity is known as surface tension. In other words, surface tension is defined as the “Force pulling tangentially along the surface of a liquid”. This force tends to make the surface area as small as possible and has the dimension of force per unit length or energy per unit area expressed in Newton/meter (N/m) or dynes/cm. As a result of this surface tension, the air-water interspace become curved.  Page 18 of 28 Soil moisture tension Soil moisture tension is the tenacity with which water is held in the soil. To remove this water, some pressure (force per unit area) must be given or exerted. This pressure or tenacity is measured in terms of potential energy of water and is expressed in atmosphere or bars. 1 atmosphere = 1036 cm water column or 76.39 cm of mercury 1 Bar = 1023 cm water column To convert the soil moisture tension to equivalent atmosphere, the above conversion ratio can be used. But here, there is no real vertical pressure of water column. Hence, it can be stated as suction or negative pressure. Hence, soil moisture tension of one atmosphere is approximately equal to suction or a negative pressure of 1000 cm of water column. At different soil moisture constants the soil moisture tension will vary. For example, the loam or clay type of soil retains moisture at a tension of 1/3 atmosphere at field capacity level, whereas the sandy soil has a tension of as low as 1/10 atmosphere. The available soil moisture is not only the function of soil physical characteristics like texture and structure but also the soil depth. Kinds of soil water The soil water can be classified into three kinds based on their nature of attachment to the soil particles. Hygroscopic water Capillary water Gravitational water Kinds of soil water i. Hygroscopic water: This is the first stage of soil water content where water is held tightly by the surface of the soil particles by the forces of adhesion or adsorption force. Hence, it is also known as water of adhesion. At this condition the tension with which water is held in soil surface is from 10,000 atmosphere to 31 atmosphere. So the plant cannot exert this much of energy to extract the water from the soil particles. Hence, it is the unavailable form of water. This condition mostly occurs at permanent wilting point stage or dry condition. ii. Capillary water: This is the next stage after attaining hygroscopic water, with reference to soil-water relationship. In this stage there is relatively better thick film of water around the soil particles and between the soil particles. Hence, the cohesive force is responsible for the attraction of water molecules with each other. At this condition some of the pore spaces are not filled with water. Only the micro pores are filled up with water and little chances for macro pores to hold water. This condition will appear at field capacity level where the water is held at a tension of one-third atmosphere to 15 atmosphere. The water is available to the plants because plants can exert the same amount of energy to extract this water. Hence, it is known as available water. When water comes in contact with the surface of soil particles, it will be attracted by the surface of the soil by adhesive force and gravitational force. At the same time there is repulsion for this attraction due to cohesive force along the liquid surface. Texture - Finer the texture greater is the capillary capacity. Structure - Granular structure produces higher capillary capacity Organic matter - More organic matter increases the capillary capacity iii. Gravitational water - It is the third stage of soil water where water that moves freely as response to gravity percolates downwards and drains out to deeper layer of soil profile. It is also known as free water. At this condition, the macro and micro pores are completely filled up with water. There is no space for air movement in soil pore spaces. This state will appear when the soil is under saturation.  Page 19 of 28 Crop water requirement Water requirement is defined as the quantity of water required by a crop or a diversified pattern of crops in a given period of time for its normal growth at a place under field conditions. The source of water may be anything like wells, tanks, artisan wells of canals of rivers. Crop water requirement is the water required by the plants for its survival, growth, development and to produce economic parts. This requirement is applied either naturally by precipitation or artificially by irrigation. Hence the crop water requirement includes all losses like: ▪ Transpiration loss through leaves (T) ▪ Evaporation loss through soil surface in cropped area (E) ▪ Amount of water used by plants (WP) for its metabolic activities, which is, estimated as less than 1% of the total water absorption These three components cannot be separated so easily. Hence, the ET loss is taken as crop water use or crop water consumptive use. Other application losses are conveyance loss, percolation loss, runoff loss etc., (WL). The water required for special purpose (WSP) like puddling operation, ploughing operation, land preparation, leaching requirement, for the purpose of weeding for dissolving fertilizers and chemicals etc. Hence, the water requirement is symbolically represented as: The crop water requirement can also be defined as water required to meet the evapotranspiration demand of the crop and special needs in case of wet land crop and which also includes other application losses both in the case of wet land and garden land crops. This is also known as crop water demand. Evaporation Evaporation is defined as the process by which water moves out of the water surface or soil surface in the form of water vapor to atmosphere due to pressure gradient. Evaporation from natural surface such as open water, bare soil or vegetative cover is a diffusive process by which water in the form of vapor is transferred from the underlying surface to the atmosphere. Transpiration Transpiration is the process by which water in plant body transfers to the atmosphere in the form of water vapor. It is the process by which water evaporates in the form of water vapor from living plant body especially from leaves to atmosphere. It involves a continuous movement of water from soil to atmosphere through root, stem and leaves. Chapter- 8 WEEDS Weed is a plant growing where it is not wanted, unwanted plant, out of place, extremely noxious, useless, and poisonous. Characteristics of weeds Weeds are like any other crops plants in size, form, morphological & physiological characters but possess the following characteristics, on account of which they are considered as enemy of crops by the farmer : i. The weed seeds germinate early and the seedlings grow faster. They being hardy, compete for light, moisture and nutrients. ii. They flower earlier, run to seed in profusion and mature ahead of the crop. They are difficult to control and it may be even impossible to eradicate some weeds completely. iii. They are non-useful, unwanted & undesirable. iv. They are harmful to crops, cattle and human beings. v. They can thrive even under adverse conditions of soil, climate, etc. vi. They are prolific and have a very high reproduction capacity. e.g.: A plant of satyanashi (Argemone mexicana) produces over 5000 seeds while a plant of striga produces over half a million seeds. vii. Viability of weed seeds remains intact, even if they are buried deep in the soil. In some cases, the seeds may remain viable even after passing through the digestive tract of the animals. viii. The seeds may have special structures like wings, spines, hooks, sticky hair, etc. on account of which they can be easily disseminated over long distances. ix. Many weeds like Cynodon dactyl on are vegetatively propagated and spread rapidly all over the field even under adverse conditions.  Page 20 of 28 Disadvantages of weeds i. Reduction in crop yield: Weeds compete for water, nutrients & light. Being hardy & vigorous in growth habit, they soon outgrow the crops & consume large amounts of water & nutrients, thus causing heavy losses in yield. e.g.: 40% reduction in yield of groundnut & 66% reduction in yield of chilli. The loss of N through weeds is about 150 kg/ha. ii. Increase in the cost of cultivation: One of the objects of tillage is to control weed on which 30% expenditure is incurred and this may increase more in heavy infested areas & also cost on weed control by weeding or chemical control. Hence, reduce margin of net profit. iii. Reduction in the quality of field produce: Weed seeds get harvested & threshed along the crop produce, which lowers the quality. Such produce fetches fewer prices in the market. e.g.: Leafy vegetables, grain crop. iv. Reduction in quality of livestock produce: Weeds impart an undesirable flavor to the milk (Ghaneri), impair quality of wool of sheep (Gokhuru, Aghada), and cause death of animals due to poisonous nature of seed (Dhatura). v. Harbour insect-pests & disease pathogens: Weeds either give shelter to various insect pests & disease pathogens or serve as alternate hosts & thus helps in perpetuating the menace from pests & diseases. e.g.: Gall fly of paddy, midge fly of Jowar, leaf minor of soybean & Groundnut, rust of Wheat, tikka of Groundnut, Black rust of wheat, Downey mildew (Saccharum spontaneum). vi. Check the flow of water in irrigation channels: Weeds block drainage & check the flow of water in irrigation canals & field channels thereby increasing the seepage losses as well as losses through over through over flowing, so reduce the irrigation efficiency. vii. Secretions are harmful: Heavy growth of certain weeds like quack grass (Agropyon repens) or lavala lowers the germination & reduce the growth of many crop plants due to presence of certain phytotoxins secreted by weeds. viii. Harmful to human beings and animals: Weeds cause irritation of skin allergy & poisoning to human beings, also death of castles. ix. Cause quicker wear & tear of farm implements: Being hardy & deep rooted; the tillage implements get worn out early & cannot work efficiently unless they are properly sharpened or mended. x. Reduce value of the lands: Heavily infested lands with perennial weeds fetch less price as require heavy expenditure to bring under cultivation. Benefits/advantages derived from weeds i. Weeds when ploughed under, add nutrients, organic matter. ii. Weeds check winds or water erosion by soil binding effect of their roots (undirkani). iii. Useful as fodder for castles (Hariyali) & vegetable by human beings (Ghol, Tandulja). iv. Have medicinal value, Leucas aspera isused aga9inst snake bite, oil of satyanashi seed is useful against skin diseases, nuts of lavala are used in making scents (Udabattis/Incense sticks). v. Have economic importance e.g.: saccharum spp used for making thatches. vi. Reclamation of alkali lands (Satyanashi). vii. Serve as ornamental plants (Ghaneri). viii. Used for fencing (Cactus, Nagphana). ix. Used as mulch to check the evaporation losses of water from soil. x. Used as green manuring & composting. xi. Fix atmospheric „N‟ (Blue green algae, Tarota, Unhali, etc.) Principles of wced Control For successful control, one has to consider the following points: a. Habits of weed plants: A xerophytes weed (e.g. Alhagi camelorum) thriving under dry & arid conditions will die if fields are flooded with water. Similarly improving drainage can control weeds, which thrive under marsh or ill drained condition of soil. b. Life cycle of the weed: Annuals & biennials can be controlled effectively if the land is cultivated before seedling stage of weeds. Perennials require deep ploughing to dig out rhizomes, bulbs, etc. vegetative part by which they propagate. c. Susceptibilities: Some weeds are susceptible to certain chemicals while others are not. e.g.: Dicots are susceptible to 2, 4-D while monocots are not, hence 2,4- D is used to control broad leaved weeds in monocot crops. d. Dormancy period: While controlling dormancy weeds, period is to be considered as they have long dormancy period. e. Resistance to adverse conditions without losing viability: Some weed seeds have hard seed coats, which enable them to remain for a long time without losing their viability, hence they should be controlled before seed formation. f. Methods of reproduction: Weeds propagate either by seeds, vegetative parts or by both. Seeded weeds should be removed or smothered before seed formation. Vegetatively propagated weeds should be exposed to sun heat to dry & die like rhizome, bulbs, solons, etc. by deep ploughing. Frequent cultivation leads to destroy green leaves & thereby exhaust the food reserves & starve the plants may have to be restored too. In weeds propagated by both mechanical & chemical methods may have to be followed.  Page 21 of 28 g. Dispersal of seeds: Weeds can be controlled or kept in check if the ways in which different weed seeds disseminate are known and counter measures are undertaken. Weed control methods Weed control methods have been broadly classified into two groups: ▪ Preventive measures ▪ Curative or Control Measures which includes: i. Mechanical ii. Cropping or cultural iii. Biological iv. Chemical Preventive measures: In this, the weeds are prevented from its multiplication, introduction & nipped off the buds. It consists of: 1. Use clean seed 2. Use well decomposed FYM/compost 3. Cut the weeds before seeding 4. Remove weed growth or keep irrigation & drainage channels clean or free from seeds 5. Avoid feeding of grain screenings, hay or fodder containing weed seeds without destroying their viability by grinding or cooking 6. Avoid use of sand or soil from weed infested areas to clean or cultivated areas 7. Avoid allowing castles to move from weed infested areas to clean or cultivated areas 8. Clean all the farm implements & machinery properly after their use in infested areas & before using in clean areas 9. Keep farm fences, roads & bunds clean or free from weeds 10. Watch seedlings in nurseries carefully so that they do not get mixed with weed seedlings & get carried to the fields Types of herbicides a. Selective herbicides are those, which kill only weeds without injuring crop plants. b. Non-selective herbicides are those which kill all kinds of vegetations i.e. weed and crop plant. c. Contact herbicides kill all the plant parts, which may get covered by the chemical, by directly killing the plant cells. These chemicals are effective against annuals particularly when they are young but not perennials. d. Translocated/systemic herbicides are first absorbed in the foliage or through roots and are then translocated to other parts of the plant or kill plants after their absorption by accelerating or retarding the metabolic activities of plants. These are more effective in destroying deep rooted perennials. Chapter - 9 CROP ROTATION Crop rotation refers to recurrent succession of crop on the same piece of land either in a year or over a longer period of time. Component crops are so chosen so that soil health is not impaired. or it means growing a set of crop in a regular succession on a piece of land in a specific period of time, with an object to get maximum profit least investment without impairing soil fertility. Characteristics of good crop rotation i. It should be adaptable to the existing soil, climatic and economic factors. ii. It should be based on proper land utilization or it should be so arranged in relation to fields that crop yields can be maintained and also build up organic matter content of the soil. iii. It should contain sufficient area under soil improving crops (legumes) to maintain and also build up organic matter content of the soil. iv. It should provide food grains, pulses, oilseed etc. to family and roughages, fodder to cattle. v. It should help in control of pests, diseases, and weeds. vi. It should provide maximum area under the most profitable crops adapted to the area. Advantages of an ideal crop production i. It increases overall yield of crops mainly due to maintaining physical- chemical properties of soil. Soil fertility is restored by fixing atmospheric nitrogen, encouraging microbial activity (more organic matter) and protecting soil from erosion, salinity and acidity. ii. It helps in controlling insects, pests and soil borne diseases. iii. It also controls weeds. e.g. repeated wheat culture increases wild oats and phallaris infestation. Similarly growing berseem continuously encourages chicory (kasani) infestation, but an alternate cropping of berseem and wheat helps in controlling kasani as well as oats and phallaris. iv. It prevents or limits periods of peak requirements of irrigation water. Crops requiring high irrigation if followed by light irrigation, this will not affect or deteriorate the soil physical condition.  Page 22 of 28 v. It facilitates even distribution of labor and crop make proper utilization of all resources and inputs. Family and farm labor, power, equipment and machines are well employed through out the year. vi. Farmers get a better price for their produce due to higher demand in local market. So there is regular flow of income over year. vii. Inclusion of crops of different feeding zones (root system) and nutrient requirement maintains the better balance of nutrient in soil. Growing crops of different root depths avoids continuous depletion of nutrients from the same depth. e.g. deep rooted crops take nutrients from deeper zone and during that period upper zone get enriched. Similarly, surface feeding roots take nutrients from upper zone when lower zone get enriched. So growing same crop without rotation results in loss of soil productivity. viii. Diversification of crops reduces risk of financial loss due to unfavorable conditions. Diversification of crops means variety of crops can be grown for meeting the domestic needs of farmers and livestock, to reduce risk of market fluctuations, mechanism of farming, growing expensive crops. So all variety of crops are grown in rotation for more benefit. ix. It improves soil structure, percolation and reduces changes of creation of hard- pan in sub soil and also reduces soil erosion. x. The family needs of feed, food, fuel, fiber, spices, sugar etc. are fulfilled and also fulfill needs of livestock. xi. Advantages of raising short duration crops (catch crop/vegetables) when long season crops cannot be raised due to some reasons. Factors affecting crop rotation a. Net profit per hectare b. Growth habit and nutrient requirement of different crops. c. Soil type and slope d. Infestation of weeds, pests and diseases e. Irrigation facilities f. Climatic conditions g. Land, labor, power and other resources h. Food habit and requirements i. Market facilities Principles of crop rotation 1. The crops with tap-root should be followed by those, which have a fibrous root system. This helps in proper and uniform use of nutrients from the soil and roots do not compete with each other for uptake of nutrients. 2. A shallow rooted grain crop, deep rooted cash crop and restorative crop (legume crop) should be included in the rotation for providing food, fodder, cash and maintaining the fertility and productivity of soil. 3. The leguminous crops should be grown after non-leguminous crops because leguminous fix atmospheric N into soil and more organic matter to soil. Apart from this, legumes need more phosphate and less nitrogen while non- legumes need more of nitrogen and relatively low phosphorus. So nutrient requirements of these crops are different and such combination helps farmers in reducing cost of cultivation. 4. Selection of the crops should be based on soil, climate, season and market demand. 5. More exhaustive crops should be followed by less exhaustive crops because crops like potato, sugarcane, maize, etc. need more inputs such as better tillage, more fertilizer higher number of irrigations, more insecticides, better care than crops like oil seeds, pulses, etc. which need little less care or little less inputs. 6. Two or three crops are taken in a year on same land under irrigated conditions. However, a dry crop should be included in the rotation to avoid damage to the soil due to continuous irrigation. 7. In case of rainfed farming on moisture retentive soils after harvest of Kharif crop some minor crop requiring less moisture like pulses or cereals may be grown. e.g. Rice (Kharif)-Gram/Wal (Rabi), Green gram or black gram-Rabi sorghum, sorghum, sorghum-gram. 8. The selection of crops should be problem based e.g. on sloppy lands which are prone to soil erosion, an alternate cropping of erosion promoting (erect growing crops like millet etc.) and erosion resisting crops like legumes, should be adopted. Selection of crops should suit the farmer’s financial conditions. 9. Both wide spaced crop and thickly planted crops should be included in rotation for control of weeds. e.g. wide spaced crops like tobacco controls weeds due to frequent inter culturing and dense ( thick ) forage or legume crops control weeds and soil erosion e.g. soybean. 10. Crops with different botanical relationship should be altered for control of weeds, pests and diseases. 11. Effect of previous crop on succeeding crop should be considered for obtaining maximum yield and harvest quality of produce. 12. Enough elasticity may be kept in rotation so that if pest or diseases destroy a crop, another crop can be substituted. 13. Fertile and well-drained land should be utilized for important good rotation, less fertile land for soil improving crops (legumes) and salt tolerant crops on acidic, saline or alkali soils.  Page 23 of 28 14. The ideal crop rotation should be built up around a hub crop for which the greatest comparative advantages exist. e.g. in areas of dairy industry oil seeds like groundnut or pulses will supply cattle feed (oil cakes and roughages) or in irrigated areas near cities, growing of vegetables or floriculture will be profitable. 15. Selection of crops should be demand based, i.e. the crops, which are needed by the people or area. So that produce can be sold at a higher price. The area devoted to each crop should be constant from year to year. Chapter-11 INTERCROPPING Intercropping is growing of two or more crops simultaneously on the same piece of land with a definite row pattern. Multiple cropping in the form of intercropping is predominant in the regions of dry, humid and semi-arid tropics. Objectives 1. Increase in total productivity per unit land area 2. Judicious utilization of resources such as land, labor and inputs. Intercropping was originally practiced as an insurance against crop failure under rainfall conditions. At present the main objective of intercropping is higher productivity per unit area in addition to stability in production. Intercropping system utilizes resources sufficiently and their productivity is increased. Important requirements for successful intercropping ▪ The time of peak nutrient demand of component crops should not overlap. In maize + green gram intercropping system, the peak nutrient demand period for green gram is around 35 DAS while it is 50 days for maize. ▪ Competition for light should be minimum among the component crops. Complementary should exist between the component crops. ▪ The differences in maturity of component crops should be at least 30 days. Advantages of intercropping 1. Intercropping gives additional yield income/unit area than sole cropping. 2. It acts as an insurance against failure of crops in abnormal year. 3. Inter-crops maintain the soil fertility as the nutrient uptake is made from both layers of soil. 4. Reduction in soil runoff and controls weeds. 5. Intercrops provide shade and support to the other crop. 6. Inter cropping system utilizes resources efficiently and their productivity is increased (Reddy and Redid, 1992). 7. Intercropping with cash crops is higher profitable. 8. It helps to avoid inter-crop competition and thus a higher number of crop plants are grown per unit area. Disadvantages of intercropping a. Yield decreases as the crops differ in their competitive abilities. b. Management of intercropping having different cultural practices seems to be difficult task c. Improved implements cannot be used efficiently. d. Higher amount of fertilizer or irrigation water cannot be utilized properly as the component crops vary in their response of these resources. e. Harvesting is difficult. Types of intercropping a. Mixed intercropping: Growing two or more crops simultaneously with no distinct row arrangement. b. Row intercropping: Growing two or more crops simultaneously where one or more crops are planted in rows. c. Strip inter-cropping: Growing two or more crops simultaneously in different strips wide enough to permit independent cultivation but narrow enough for the crops to interact ergonomically. d. Relay inter-cropping: Growing two or more crops simultaneously during part of the life cycle of each. A second crop is planted after the first crop has reached its reproductive stage but before it is ready for harvest.  Page 24 of 28 Chapter – 18 CALCULATION ON MANURE AND FERTILIZERS, PLANT POPULATION, SEED RATES, AND HERBICIDES Calculation of manure/fertilizers Problem 1. Calculate the quantity of urea, SSP and MOP required for 1 ha of rice. Recommended dose of NPK is 100:50:50 kg/ha, respectively. Answer: The required amount of urea, SSP and MOP/ha will be 217.4, 312.5 and 83.33 kg, respectively. Problem 2. Calculate the quantity of required NPK for 2 ha of wheat. Recommended dose of urea, SSP and MOP is 120:60:60 kg/ha, respectively. 16 x 8.3 kg Answer: The required amount of N, P&K will be 110.4, 8.3 and 59.76 kg, respectively.  Page 25 of 28 Problem 3. Calculate the quantity of urea, DAP and MOP required for 1 ha of rice. Recommended dose of NPK is 100:50:50 kg/ha, respectively Answer: The required quantity of DAP, urea and MOP will be 108.69, 174.84 and 83.33kg, respectively. Problem 4. Calculate the amount of nutrient from 3:2:1 graded 1ton fertilizer  Page 26 of 28 __________________________________________________________________________ _  Page 27 of 28 Calculation of crop plant population Problem 1. Calculate number of maize plants in one ha area if inter and intra spacing is 60cm and 20 cm, respectively. 2 Given area (m ) Number of plants in a given area = ------------------------------------------ 2 Area required by single plant (m ) 2 1 ha = 10000 m 2 Area required by single plant (m ) = inter spacing/100 x intra spacing/100 = 60/100 x 20/100 or 0.6x0.2 or 1.2 Number of plants/ha = 10000/1.2 = 8333.33 or 8333 Problem 2. Calculate number of wheat plants in 400m2 area if inter and intra spacing is 22cm and 10cm, respectively. 2 Given area (m ) Number of plants in a given area = ------------------------------------------ 2 Area required by single plant (m ) 2 Area required by single plant (m ) = inter spacing/100 x intra spacing/100 2 Area required by single plant (m ) = inter spacing/100 x intra spacing/100 Number of plants = 400/0.022 = 18181.81 or 18182 Calculation of seed rates Recommended quantity of crop seed (kg) per ha or square meters Seed required = ----- ------------------------------------------------------------------------ for the area (kg) Given area in ha or square meters Problem 1. Calculate the seed quantity of wheat for one kanal if seed rate is 100kg/ha. 2 2 1 kanal = 400m 1 ha = 10000m Quantity of seed required = 100x400/10000 = 4kg  Page 28 of 28 Calculation of herbicide dose Problem 1. Calculate the quantity of stomp (Pendimethalin 35% EC) for 1 ha with recommended dose of 1.5L a.i. per ha. Problem 2. Calculate the a.i. quantity of Pendimethalin for 1 ha with the recommended dose of Stomp (35EC) @ 4.29 L per ha. Solution 1. 100 Quantity of herbicide (l or kg/ha) = -------- x Recommended dose of herbicide ( l or kg a.i/ha) Conce of herbicide 100 Quantity of Stomp (L/ha) = ------- x Recommended dose of herbicide (l a.i/ha) Conce of herbicide = 100/35 x 1.5 = 4.285 l/ha Answer = 4.285 l/ha Solution 2. Conce of herbicide Quantity of herbicide (l or kg a.i./ha) = -------- x Recommended dose of herbicide (l or kg/ha) 100 Conce of herbicide Quantity of Stomp (l/ha) = ---------- x Recommended dose of herbicide (l a.i/ha) 100 = 35/100 x 4.29 = 1.5 l/ha Answer = 1.5 l/ha Note: Water for making solution is used @ 750 l per hectare References 1. Chandrasekaran B, Annadurai K and Somasundaram E. 2010. A text Book of Agronomy. New Age International Publishers, New Delhi 2. Cheema SS, Dhaliwal BK and Sahota TS. 1991. Agronomy - Theory and Digest (1st edition). Kalyani Publishers, Ludhiana 3. Harris, D.R., Fuller, D.Q. (2014). Agriculture: Definition and Overview. In: Smith, C. (eds) Encyclopedia of Global Archaeology. Springer, New York, NY. https://doi.org/10.1007/978-1-4419-0465-2_64. 4. Marin JH, Leonard WH and Stamp DL.1976. Principles of Field Crop Production (3rd edition). Macmillan Publishing Co., Inc. Newyork and Collier Macmillan Publishers, London 5. Pratley J. 2003. Principles of Field Crop Production (4th edition). Oxford University Press, Australia 6. Reddy SR. 2000. Principles of Crop Production (1stedition). Kalyani Publishers, Ludhiana 7. Reddy SR. 2006. Agronomy of Field Crops (2nd revised edition). Kalyani Publishers, Ludhiana 8. Reddy TY and Reddy GHS. 2005. Principles of Agronomy (3rd revised edition, 2002 and reprinted in 2005). Kalyani Publishers, Ludhiana 9. Singh J. 2015. Teaching Manual on Introductory Agriculture. College of Agriculture, CSKHPKV, Palampur, India 10. Singh J. and Abraha, T. 2007. Teaching Manual on Principles of Crop Production. a. Hamelmalo Agriculture College, Keren, Eritrea, NE Africa 11. Smith, WC. 1995. Crop Production (Evolution, History and technology), John Willey & Sons. Inc., Newyork, Tronto, Singapur th 12. Tisdale SL, Nelson WL, Beaton, JD and Havlin, JL.1993. Soil Fertility and Fertilizersm (5 edition), Macmillan Publishing Co., Inc. New york