Improvement In Food Resources PDF

Chapter 15 IMPROVEMENT IN FOOD R ESOURCES We know that all living organisms need food. Hence, there is a need for sustainable Food supplies proteins, carbohydrates, fats, practices in agriculture and animal vitamins and minerals, all of which we require husbandry. for body d...

Chapter 15 IMPROVEMENT IN FOOD R ESOURCES We know that all living organisms need food. Hence, there is a need for sustainable Food supplies proteins, carbohydrates, fats, practices in agriculture and animal vitamins and minerals, all of which we require husbandry. for body development, growth and health. Also, simply increasing grain production Both plants and animals are major sources for storage in warehouses cannot solve the of food for us. We obtain most of this food problem of malnutrition and hunger. People from agriculture and animal husbandry. should have money to purchase food. Food We read in newspapers that efforts are security depends on both availability of food always being made to improve production and access to it. The majority of our from agriculture and animal husbandry. Why population depends on agriculture for their is this necessary? Why we cannot make do livelihood. Increasing the incomes of people with the current levels of production? working in agriculture is therefore necessary India is a very populous country. Our to combat the problem of hunger. Scientific population is more than one billion people, management practices should be undertaken and it is still growing. As food for this growing to obtain high yields from farms. For population, we will soon need more than a sustained livelihood, one should undertake quarter of a billion tonnes of grain every year. mixed farming, intercropping, and integrated This can be done by farming on more land. farming practices, for example, combine But India is already intensively cultivated. As agriculture with livestock/poultry/fisheries/ a result, we do not have any major scope for bee-keeping. increasing the area of land under cultivation. The question thus becomes – how do we Therefore, it is necessary to increase our increase the yields of crops and livestock? production efficiency for both crops and livestock. 15.1 Improvement in Crop Yields Efforts to meet the food demand by increasing food production have led to some Cereals such as wheat, rice, maize, millets successes so far. We have had the green and sorghum provide us carbohydrate for revolution, which contributed to increased energy requirement. Pulses like gram (chana), food-grain production. We have also had the pea (matar), black gram (urad), green gram white revolution, which has led to better and (moong), pigeon pea (arhar), lentil (masoor), more efficient use as well as availability of milk. provide us with protein. And oil seeds However, these revolutions mean that our including soyabean, ground nut, sesame, natural resources are getting used more castor, mustard, linseed and sunflower intensively. As a result, there are more provide us with necessary fats (Fig. 15.1). chances of causing damage to our natural Vegetables, spices and fruits provide a range resources to the point of destroying their of vitamins and minerals in addition to small balance completely. Therefore, it is important amounts of proteins, carbohydrates and fats. that we should increase food production In addition to these food crops, fodder crops without degrading our environment and like berseem, oats or sudan grass are raised disturbing the balances maintaining it. as food for the livestock.  the kharif season from the month of June to October, and some of the crops are grown in the winter season, called the rabi season from November to April. Paddy, soyabean, pigeon pea, maize, cotton, green gram and black gram are kharif crops, whereas wheat, gram, peas, mustard, linseed are rabi crops. In India there has been a four times increase in the production of food grains from 1952 to 2010 with only 25% increase in the cultivable land area. How has this increase in production been achieved? If we think of the practices involved in farming, we can see that we can divide it into three stages. The first is the choice of seeds for planting. The second is the nurturing of the crop plants. The third is the protection of the growing and harvested crops from loss. Thus, the major groups of activities for improving crop yields can be classified as: Crop variety improvement Crop production improvement Crop protection management. 15.1.1 CROP VARIETY IMPROVEMENT This approach depends on finding a crop variety that can give a good yield. Varieties or strains of crops can be selected by breeding for various useful characteristics such as disease resistance, response to fertilisers, Fig. 15.1: Different types of crops product quality and high yields. One way of Q incorporating desirable characters into crop varieties is by hybridisation. Hybridisation uestion refers to crossing between genetically 1. What do we get from cereals, dissimilar plants. This crossing may be pulses, fruits and vegetables? intervarietal (between different varieties), interspecific (between two different species of the same genus) or intergeneric (between different genera). Another way of improving Different crops require different climatic the crop is by introducing a gene that would conditions, temperature and photoperiods for provide the desired characteristic. This their growth and completion of their life cycle. results in genetically modified crops. Photoperiods are related to the duration of For new varieties of crops to be accepted, sunlight. Growth of plants and flowering are it is necessary that the variety produces high dependent on sunlight. As we all know, plants yields under different conditions that are manufacture their food in sunlight by the found in different areas. Farmers would need process of photosynthesis. There are some to be provided with good quality seeds of a crops, which are grown in rainy season, called particular variety, that is, the seeds should 204 SCIENCE all be of the same variety and germinate under that less nutrients are consumed by the same conditions. these crops. Thus developing varieties Cultivation practices and crop yield are of desired agronomic characters help Q related to weather, soil quality and availability give higher productivity. of water. Since weather conditions such as drought and flood situations are uestions unpredictable, varieties that can be grown in diverse climatic conditions are useful. 1. How do biotic and abiotic factors Similarly, varieties tolerant to high soil salinity affect crop production? have been developed. Some of the factors for 2. What are the desirable agronomic which variety improvement is done are: characteristics for crop Higher yield: To increase the improvements? productivity of the crop per acre. Improved quality: Quality considerations of crop products vary from crop to crop. Baking quality is 15.1.2 C ROP PRODUCTION MANAGEMENT important in wheat, protein quality in In India, as in many other agriculture-based pulses, oil quality in oilseeds and countries, farming ranges from small to very preserving quality in fruits and large farms. Different farmers thus have more vegetables. or less land, money and access to information Biotic and abiotic resistance: Crops and technologies. In short, it is the money or production can go down due to biotic financial conditions that allow farmers to take (diseases, insects and nematodes) and up different far ming practices and abiotic (drought, salinity, water logging, heat, cold and frost) stresses agricultural technologies. There is a under different situations. Varieties correlation between higher inputs and yields. resistant to these stresses can improve Thus, the farmer’s purchasing capacity for crop production. inputs decides cropping system and Change in maturity duration: The production practices. Therefore, production shorter the duration of the crop from practices can be at different levels. They sowing to harvesting, the more include ‘no cost’ production, ‘low cost’ economical is the variety. Such short production and ‘high cost’ production durations allow farmers to grow practices. multiple rounds of crops in a year. Short duration also reduces the cost 15.1.2 (i) NUTRIENT MANAGEMENT of crop production. Uniform maturity makes the harvesting process easy Just as we need food for development, growth and reduces losses during harvesting. and well-being, plants also require nutrients Wider adaptability: Developing for growth. Nutrients are supplied to plants varieties for wider adaptability will by air, water and soil. There are sixteen help in stabilising the crop production nutrients which are essential for plants. Air under different environmental supplies carbon and oxygen, hydrogen comes conditions. One variety can then be from water, and soil supplies the other grown under dif ferent climatic thirteen nutrients to plants. Amongst these conditions in different areas. thirteen nutrients, six are required in large Desirable agronomic characteristics: quantities and are therefore called macro- Tallness and profuse branching are nutrients. The other seven nutrients are used desirable characters for fodder crops. by plants in small quantities and are therefore Dwarfness is desired in cereals, so called micro-nutrients (Table 15.1). I MPROVEMENT IN FOOD R ESOURCES 205  our environment from excessive use of Table 15.1: Nutrients supplied fertilizers. Using biological waste material is by air, water and soil also a way of recycling farm waste. Based on the kind of biological material used, manure Source Nutrients can be classified as: (i) Compost and vermi-compost: The Air carbon, oxygen process in which farm waste material like livestock excreta (cow dung etc.), Water hydrogen, oxygen vegetable waste, animal refuse, domestic waste, sewage waste, straw, Soil (i) Macronutrients: eradicated weeds etc. is decomposed nitrogen, phosphorus, in pits is known as composting. The potassium, calcium, compost is rich in organic matter and magnesium, sulphur nutrients. Compost is also prepared (ii) Micronutrients: by using earthworms to hasten the iron, manganese, boron, process of decomposition of plant and zinc, copper, animal refuse. This is called vermi- molybdenum, chlorine compost. (ii) Green manure: Prior to the sowing of Deficiency of these nutrients affects the crop seeds, some plants like sun physiological processes in plants including hemp or guar are grown and then reproduction, growth and susceptibility to mulched by ploughing them into the diseases. To increase the yield, the soil can soil. These green plants thus turn into be enriched by supplying these nutrients in green manure which helps in Q the form of manure and fertilizers. enriching the soil in nitrogen and phosphorus. uestions 1. What are macro-nutrients and FERTILIZERS why are they called macro- Fertilizers are commercially produced plant nutrients? nutrients. Fertilizers supply nitrogen, 2. How do plants get nutrients? phosphorus and potassium. They are used to ensure good vegetative growth (leaves, branches and flowers), giving rise to healthy plants. Fertilizers are a factor in the higher MANURE yields of high-cost farming. Fertilizers should be applied carefully in Manure contains large quantities of organic terms of proper dose, time, and observing pre- matter and also supplies small quantities of and post-application precautions for their nutrients to the soil. Manure is prepared by complete utilisation. For example, sometimes the decomposition of animal excreta and plant fertilizers get washed away due to excessive waste. Manure helps in enriching soil with irrigation and are not fully absorbed by the nutrients and organic matter and increasing plants. This excess fertilizer then leads to soil fertility. The bulk of organic matter in water pollution. manure helps in improving the soil structure. Also, as we have seen in the previous This involves increasing the water holding chapter, continuous use of fertilizers in an capacity in sandy soils. In clayey soils, the area can destroy soil fertility because the large quantities of organic matter help in organic matter in the soil is not replenished drainage and in avoiding water logging. and micro-organisms in the soil are harmed In using manure we use biological waste by the fertilizers used. Short-term benefits of material, which is advantageous in protecting using fertilizers and long-term benefits of 206 SCIENCE using manure for maintaining soil fertility have India has a wide variety of water resources to be considered while aiming for optimum and a highly varied climate. Under such yields in crop production. conditions, several different kinds of irrigation Q systems are adopted to supply water to uestion agricultural lands depending on the kinds of water resources available. These include 1. Compare the use of manure and wells, canals, rivers and tanks. fertilizers in maintaining soil Wells: There are two types of wells, fertility. namely dug wells and tube wells. In a dug well, water is collected from water Organic farming is a farming system with bearing strata. Tube wells can tap minimal or no use of chemicals as fertilizers, water from the deeper strata. From herbicides, pesticides etc. and with a these wells, water is lifted by pumps maximum input of organic manures, recycled for irrigation. farm-wastes (straw and livestock excreta), use Canals: This is usually an elaborate of bio-agents such as culture of blue green and extensive irrigation system. In this algae in preparation of biofertilizers, neem system canals receive water from one leaves or turmeric specifically in grain storage or more reservoirs or from rivers. The as bio-pesticides, with healthy cropping main canal is divided into branch systems [mixed cropping, inter-cropping and canals having further distributaries to crop rotation as discussed below in irrigate fields. 15.1.2.(iii)]. These cropping systems are River Lift Systems: In areas where beneficial in insect, pest and wheat control canal flow is insufficient or irregular besides providing nutrients. due to inadequate reservoir release, the lift system is more rational. Water 15.1.2 (ii) IRRIGATION is directly drawn from the rivers for Most agriculture in India is rain-fed, that is, supplementing irrigation in areas the success of crops in most areas is close to rivers. dependent on timely monsoons and sufficient T anks: These ar e small storage rainfall spread through most of the growing reservoirs, which intercept and store season. Hence, poor monsoons cause crop the run-of f of smaller catchment failure. Ensuring that the crops get water at areas. the right stages during their growing season Fresh initiatives for increasing the water can increase the expected yields of any crop. available for agriculture include rainwater Therefore, many measures are used to bring harvesting and watershed management. This more and more agricultural land under involves building small check-dams which irrigation. lead to an increase in ground water levels. The check-dams stop the rainwater from Droughts occur because of scarcity or flowing away and also reduce soil erosion. irregular distribution of rains. Drought poses a threat to rain-fed farming 15.1.2 (iii) CROPPING PATTERNS More to know areas, where farmers do not use irrigation for crop production and Different ways of growing crops can be used depend only on rain. Light soils have to give maximum benefit. less water retention capacity. In areas Mixed cropping is growing two or more with light soils, crops get adversely crops simultaneously on the same piece of af fected by drought conditions. land, for example, wheat + gram, or wheat + Scientists have developed some crop mustard, or groundnut + sunflower. This varieties which can tolerate drought reduces risk and gives some insurance conditions. against failure of one of the crops. I MPROVEMENT IN FOOD R ESOURCES 207  Inter-cropping is growing two or more (gokhroo), Parthenium (gajar ghas), crops simultaneously on the same field in a Cyperinus rotundus (motha). They compete definite pattern (Fig.15.2). A few rows of one for food, space and light. Weeds take up crop alternate with a few rows of a second nutrients and reduce the growth of the crop. crop, for example, soyabean + maize, or finger Therefore, removal of weeds from cultivated millet (bajra) + cowpea (lobia). The crops are fields during the early stages of crop growth is selected such that their nutrient essential for a good harvest. requirements are different. This ensures Generally insect pests attack the plants maximum utilisation of the nutrients in three ways: (i) they cut the root, stem and supplied, and also prevents pests and leaf, (ii) they suck the cell sap from various diseases from spreading to all the plants parts of the plant, and (iii) they bore into stem belonging to one crop in a field. This way, and fruits. They thus affect the health of the both crops can give better returns. crop and reduce yields. Diseases in plants are caused by pathogens such as bacteria, fungi and viruses. These pathogens can be present in and transmitted through the soil, water and air. Weeds, insects and diseases can be controlled by various methods. One of the most commonly used methods is the use of pesticides, which include herbicides, insecticides and fungicides. These chemicals are sprayed on crop plants or used for treating seeds and soil. However, excessive use of these chemicals creates problems, since they can be poisonous to many plant and animal species and cause environmental pollution. Weed control methods also include mechanical removal. Preventive methods Fig. 15.2 : Intercropping such as proper seed bed preparation, timely sowing of crops, intercropping and crop The growing of different crops on a piece rotation also help in weed control. Some other of land in a pre-planned succession is known preventive measures against pests are the use as crop rotation. Depending upon the of resistant varieties, and summer ploughing, duration, crop rotation is done for different in which fields are ploughed deep in summers Q crop combinations. The availability of to destroy weeds and pests. moisture and irrigation facilities decide the choice of the crop to be cultivated after one uestion harvest. If crop rotation is done properly then two or three crops can be grown in a year 1. Which of the following conditions with good harvests. will give the most benefits? Why? (a) Farmers use high-quality seeds, do not adopt 15.1.3 CROP PROTECTION MANAGEMENT irrigation or use fertilizers. Field crops are infested by a large number of (b) Farmers use ordinary weeds, insect pests and diseases. If weeds and seeds, adopt irrigation and pests are not controlled at the appropriate use fertilizer. time then they can damage the crops so much (c) Farmers use quality seeds, that most of the crop is lost. adopt irrigation, use Weeds are unwanted plants in the fertilizer and use crop cultivated field, for example, Xanthium protection measures. 208 SCIENCE  Table 15.2: Nutritional values of animal products Animal Per cent (%) Nutrients Products Fat Protein Sugar Minerals Water Vitamins Milk (Cow) 3.60 4.00 4.50 0.70 87.20 B1, B2, B12, D, E Egg 12.00 13.00 * 1.00 74.00 B2, D Meat 3.60 21.10 * 1.10 74.20 B2, B12 Fish 2.50 19.00 * 1.30 77.20 Niacin, D, A *Present in very small amounts Activity _____________ 15.1 Activity _____________ 15.2 Visit a weed-infested field in the month Make a herbarium of cer eals, pulses of July or August and make a list of and oil seeds and identify the seasons the weeds and insect pests in the field. of their sowing and harvesting. STORAGE OF GRAINS 15.2 Animal Husbandry Storage losses in agricultural produce can be Animal husbandry is the scientific very high. Factors responsible for such losses management of animal livestock. It includes are biotic— insects, rodents, fungi, mites and various aspects such as feeding, breeding and bacteria, and abiotic— inappropriate disease control. Animal-based farming moisture and temperatures in the place of includes cattle, goat, sheep, poultry and fish storage. These factors cause degradation in farming. As the population increases and as quality, loss in weight, poor germinability, living standards increase, the demand for discolouration of produce, all leading to poor milk, eggs and meat is also going up. Also, marketability. These factors can be controlled the growing awareness of the need for by proper treatment and by systematic humane treatment of livestock has brought in new limitations in livestock farming. Thus, management of warehouses. livestock production also needs to be Preventive and control measures are used improved. before grains are stored for future use. They include strict cleaning of the produce before storage, proper drying of the produce first in 15.2.1 C ATTLE FARMING sunlight and then in shade, and fumigation Cattle husbandry is done for two purposes— Q using chemicals that can kill pests. milk and draught labour for agricultural work such as tilling, irrigation and carting. Indian uestions cattle belong to two different species, Bos indicus, cows, and Bos bubalis, buffaloes. 1. Why should preventive measures Milk-producing females are called milch and biological control methods be animals (dairy animals), while the ones used preferred for protecting crops? for farm labour are called draught animals. 2. What factors may be responsible Milk production depends, to some extent, for losses of grains during on the duration of the lactation period, storage? meaning the period of milk production after I MPROVEMENT IN FOOD R ESOURCES 209  loose hair. They should be sheltered under well-ventilated roofed sheds that protect them from rain, heat and cold. The floor of the cattle shed needs to be sloping so as to stay dry and to facilitate cleaning. The food requirements of dairy animals a re of two types: (a) maintenance requirement, which is the food required to support the animal to live a healthy life, and (b) milk producing requirement, which is the type of food required during the lactation period. Animal feed includes: (a) roughage, which is largely fibre, and (b) concentrates, which are low in fibre and contain relatively high levels of proteins and other nutrients. Cattle need balanced rations containing all nutrients in proportionate amounts. Besides such nutritious food material, certain feed Fig. 15.3: Indigenous milch breed of cattle additives containing micronutrients promote the health and milk output of dairy animals. the birth of a calf. So, milk production can be Cattle suffer from a number of diseases. increased by increasing the lactation period. The diseases, besides causing death, reduce Exotic or foreign breeds (for example, Jersey, milk production. A healthy animal feeds Brown Swiss) are selected for long lactation regularly and has a normal posture. The periods, while local breeds (for example, Red parasites of cattle may be both external Sindhi, Sahiwal) show excellent resistance to parasites and internal parasites. The external diseases. The two can be cross-bred to get parasites live on the skin and mainly cause animals with both the desired qualities. skin diseases. The internal parasites like worms, affect stomach and intestine while Q uestion flukes damage the liver. Infectious diseases are also caused by bacteria and viruses. 1. Which method is commonly used Vaccinations are given to farm animals for improving cattle breeds and against many major viral and bacterial why? diseases. 15.2.2 POUL TRY FARMING Activity _____________ 15.3 Poultry farming is undertaken to raise Visit a livestock farm. Note the domestic fowl for egg production and chicken following: meat. Therefore, improved poultry breeds are (1) Number of cattle and number of developed and farmed to produce layers for different breeds. eggs and broilers for meat. (2) The amount of daily milk production The cross-breeding programmes between from the different breeds. Indian (indigenous, for example, Aseel) and Proper cleaning and shelter facilities for foreign (exotic, for example, Leghorn) breeds cows and buffaloes are required for humane for variety improvement are focused on to farming, for the health of the animals and develop new varieties for the following for production of clean milk as well. Animals desirable traits— require regular brushing to remove dirt and (i) number and quality of chicks; 210 SCIENCE  (ii) dwarf broiler parent for commercial The ration (daily food requirement) for broilers chick production; is protein rich with adequate fat. The level of (iii) summer adaptation capacity/ vitamins A and K is kept high in the poultry tolerance to high temperature; feeds. (iv) low maintenance requirements; Poultry fowl suffer from a number of (v) reduction in the size of the egg-laying diseases caused by virus, bacteria, fungi, bird with ability to utilise more parasites, as well as from nutritional fibrous cheaper diets formulated deficiencies. These necessitate proper using agricultural by-products. cleaning, sanitation, and spraying of disinfectants at regular intervals. Appropriate vaccination can prevent the occurrence of infectious diseases and reduce loss of poultry during an outbreak of disease. Q uestions 1. What management practices are common in dairy and poultry farming? Aseel Leghorn 2. What are the differences between broilers and layers and in their Q Fig. 15.4 management? uestion Activity _____________ 15.4 1. Discuss the implications of the following statement: Visit a local poultry farm. Observe types “It is interesting to note that of breeds and note the type of ration, poultry is India’s most efficient housing and lighting facilities given to them. Identify the growers, layers and converter of low fibre food stuff broilers. (which is unfit for human consumption) into highly nutritious animal protein food.” 15.2.3 FISH PRODUCTION EGG AND BROILER PRODUCTION Fish is a cheap source of animal protein for our food. Fish production includes the finned Broiler chickens are fed with vitamin-rich true fish as well as shellfish such as prawns supplementary feed for good growth rate and and molluscs. There are two ways of obtaining better feed efficiency. Care is taken to avoid fish. One is from natural resources, which is mortality and to maintain feathering and called capture fishing. The other way is by carcass quality. They are produced as broilers fish farming, which is called culture fishery. and sent to market for meat purposes. The water source of the fish can be either For good production of poultry birds, good seawater or fresh water, such as in rivers and management practices are important. These ponds. Fishing can thus be done both by include maintenance of temperature and capture and culture of fish in marine and hygienic conditions in housing and poultry freshwater ecosystems. feed, as well as prevention and control of diseases and pests. 15.2.3 (i) MARINE FISHERIES The housing, nutritional and environmental requirements of broilers are India’s marine fishery resources include somewhat different from those of egg layers. 7500 km of coastline and the deep seas I MPROVEMENT IN FOOD R ESOURCES 211 beyond it. Popular marine fish varieties In such a system, a combination of five or include pomphret, mackerel, tuna, sardines, six fish species is used in a single fishpond. and Bombay duck. Marine fish are caught These species are selected so that they do using many kinds of fishing nets from fishing not compete for food among them having boats. Yields are increased by locating large different types of food habits. As a result, the schools of fish in the open sea using satellites food available in all the parts of the pond is and echo-sounders. used. As Catlas are surface feeders, Rohus Some marine fish of high economic value feed in the middle-zone of the pond, Mrigals are also farmed in seawater. This includes and Common Carps are bottom feeders, and finned fishes like mullets, bhetki, and pearl Grass Carps feed on the weeds, together these spots, shellfish such as prawns (Fig. 15.5), species (Fig. 15.6) can use all the food in the mussels and oysters as well as seaweed. pond without competing with each other. This Oysters are also cultivated for the pearls increases the fish yield from the pond. they make. (a) (b) Macrobrachium rosenbergii Peneaus monodon (fresh water) (marine) Fig. 15.5 : Fresh water and marine prawns (c) (d) As marine fish stocks get further depleted, the demand for more fish can only be met by such culture fisheries, a practice called mariculture. 15.2.3 (ii) I NLAND FISHERIES (e) Fresh water resources include canals, ponds, (f) reservoirs and rivers. Brackish water resources, where seawater and fresh water Fig. 15.6: (a) Catla (b) Silver carp (c) Rohu (d) Grass mix together, such as estuaries and lagoons Carp (e) Mrigal (f) Common Carp are also important fish reservoirs. While capture fishing is also done in such inland One problem with such composite fish water bodies, the yield is not high. Most fish culture is that many of these fish breed only production from these resources is through during monsoon. Even if fish seed is collected aquaculture. from the wild, it can be mixed with that of Fish culture is sometimes done in other species as well. So, a major problem in combination with a rice crop, so that fish are fish farming is the lack of availability of good- grown in the water in the paddy field. More quality seed. To overcome this problem, ways intensive fish farming can be done in have now been worked out to breed these fish composite fish culture systems. Both local in ponds using hormonal stimulation. This and imported fish species are used in such has ensured the supply of pure fish seed in systems. desired quantities. 212 SCIENCE Q uestions 1. How are fish obtained? 2. What are the advantages of composite fish culture? Activity _____________ 15.5 Visit a fish farm in fish breeding (a) (b) season and note the following: (1) Varieties of fish in the ponds Fig. 15.7: (a) Arrangement of beehive in an apiary (2) Types of ponds (b) honey extractor (3) Feed ingredients being used in the farm (4) Find out what the pr oduction The Italian bees have high honey collection capacity of the farm is capacity. They sting somewhat less. They stay in a given beehive for long periods, and breed 15.2.4 BEE-KEEPING very well. For commercial honey production, bee farms or apiaries are established. Honey is widely used and therefore bee- The value or quality of honey depends keeping for making honey has become an upon the pasturage, or the flowers available agricultural enterprise. Since bee-keeping to the bees for nectar and pollen collection. needs low investments, farmers use it as an additional income generating activity. In In addition to adequate quantity of pasturage, addition to honey, the beehives are a source the kind of flowers available will determine of wax which is used in various medicinal the taste of the honey. Q preparations. The local varieties of bees used for uestions commercial honey production are Apis cerana 1. What are the desirable indica, commonly known as the Indian bee, A. dorsata, the rock bee and A. florae, the characters of bee varieties little bee. An Italian bee variety, A. mellifera, suitable for honey production? has also been brought in to increase yield of 2. What is pasturage and how is it honey. This is the variety commonly used for related to honey production? commercial honey production. What you have learnt There are thirteen nutrients essential for crops. Of these, six are required in large quantities and are known as macro- nutrients whereas seven nutrients are required in small quantities and are known as micro-nutrients. Manure and fertilizers are the main sources of nutrient supply to crops. I MPROVEMENT IN FOOD R ESOURCES 213  Organic farming is a farming system with minimal or no use of chemicals as fertilizers, herbicides, pesticides etc. and with a maximum input of organic manures, recyled farm wastes, and bio-agents, with healthy cropping systems. Mixed farming is a system of farming on a particular farm which includes crop production, raising of livestock etc. Mixed cropping is growing of two or more crops simultaneously on the same piece of land. Growing two or more crops in definite row patterns is known as inter-cropping. The growing of different crops on a piece of land in pre-planned succession is called crop rotation. Varietal improvement is required for higher yield, good quality, biotic and abiotic resistance, shortening the maturity duration, wider adaptability and desirable agronomic characteristics. Farm animals require proper care and management such as shelter, feeding, breeding and disease control. This is called animal husbandry. Poultry farming is done to raise domestic fowls. Poultry production includes egg production and broiler production for poultry meat. To enhance poultry production, cross breeding is done between Indian and exotic breeds for variety improvement. Fish may be obtained from marine resources as well as inland resources. To increase production of fish, they can be cultured in marine and inland ecosystems. Marine fish capture is done by fishing nets guided by echo- sounders and satellites. Composite fish culture system is commonly used for fish farming. Bee-keeping is done to get honey and wax. Exercises 1. Explain any one method of crop production which ensures high yield. 2. Why are manure and fertilizers used in fields? 3. What are the advantages of inter-cropping and crop rotation? 4. What is genetic manipulation? How is it useful in agricultural practices? 214 SCIENCE  5. How do storage grain losses occur? 6. How do good animal husbandry practices benefit farmers? 7. What are the benefits of cattle farming? 8. For increasing production, what is common in poultry, fisheries and bee-keeping? 9. How do you differentiate between capture fishing, mariculture and aquaculture? I MPROVEMENT IN FOOD R ESOURCES 215