Class 9th Science: Chapter 15 Improvement in Food Resources
Improvement of Crop Resources
Food is essential for all living organisms to live. We depend on plants and animals for food. The increase in population has created much demand for food. The green revolution contributed to increased food-grain production, and the white revolution contributed to increased availability of milk.
Nutrients in the food
Five main nutrients of our food are carbohydrates, proteins, fats, vitamins and minerals.
Cereals provide carbohydrates, pulses provide proteins, oil seeds provide fats, vegetables, spices and fruits provide vitamins and minerals.
Types of crops
Based on the climatic conditions required for growth, crops are categorized into three types namely, kharif crops, rabi crops and zaid crops.
• Kharif crops are grown in the rainy season which extends from June to October. Kharif crops include paddy, soyabean, maize, cotton, green gram and black gram.
• Rabi crops are grown in the winter season which extends from November to April. Rabi crops include wheat, gram, peas and linseed.
• Zaid crops are grown from March to June. Zaid crops include muskmelon, Watermelon, vegetables of cucurbitaceae.
Increased production of food grains
In India, the production of food grains increased four times from 1960 to 2000. This increase in food production was due to crop variety improvement, crop production improvement and crop protection management.
Crop variety improvement: Crop variety improvement brings in following advantages.
a)Increase in the crop yield
b)Increase in the quality of the crop
c)Development of biotic and abiotic resistant crops.
d)Development of crops with shorter maturity duration.
e)Development of crops with wider adaptability.
f) Introduction of desirable characteristics in crops.
Crop variety improvement can be achieved by the process of selection.
• The criteria for selection are high yield, disease resistance, response to fertilisers, tolerance to climate, etc.
• Hybridisation occurs by a cross between two different varieties, which is known as inter-varietal crossing, or between two different genera, known as inter-generic crossing, or between two different species, known as inter-specific crossing.
• Crop yield can also be increased by introducing desirable genes into the crop plant. Crop yield is related to factors like weather, soil fertility, and availability of water etc. This results in genetically modified crop plants that are able to survive in a drought or flood.
Crop production improvement: It is the protection of crops that are growing or have been harvested. Nutrient management, irrigation and cropping patterns can help improve crop production.
Nutrients required by the plant are calssified into macronutrients and micronutrients. Air supplies carbon and oxygen. Water supplies hydrogen and oxygen. Soil supplies the remaining 13 nutrients to plants. Deficiency of any one of these diseases makes the plant prone to many diseases.
a)Macronutrients are the nutrients required in larger amounts by the plant. Macronutrients include Nitrogen, Phosphorous, Potassium, Calcium, Magnesium and Sulphur.
b)Micronutrients are the nutrients required in smaller amounts by the plant. Micronutrients include Iron, Manganese, Boron, Zinc, Copper, Molybdenum and Chlorine.
Nutrients are replenished into the soil by various methods.
• Manure is produced naturally by the decomposition of animal excreta and plant waste. It contains organic matter, and thus, improves the water-holding capacity in sandy soils, and prevents water logging in clayey soils.
• Compost is prepared by decomposing farm waste, vegetable waste, domestic and sewage waste in pits by the process of composting.
• Vermicompost is prepared by using earthworms to hasten the decomposition of plant and animal waste by the process of vermi-composting.
• Green manure is provided to the plants by ploughing plants rich in nitrogen and phosphorous into the soil before sowing seeds.
• The continuous use of chemical fertilisers kills useful micro-organisms and even destroys soil fertility. Hence, chemical fertilisers are being replaced by bio-fertilisers.
• Biofertilisers are used in organic farming to increase soil fertility. They are prepared by using organisms like blue-green algae. Neem leaves and turmeric are used as biopesticides.
Irrigation is the artificial supply of water to the soil by different methods.
• Irrigation provides water to the plants.
• Irrigation is done by both traditional methods and modern methods.
• Different sources of water are rivers, canals, ponds, lakes, tanks, dams, ground water etc.
• Fields which do not have any water supply from rivers are irrigated by dug wells or tube wells.
• Canals also provide water to crops by obtaining water from reservoirs and rivers.
Cropping pattern helps in the production of more grains in a year. Different cropping patterns are mixed cropping, inter-cropping and crop rotation.
• Mixed cropping is growing two or more crops simultaneously on the same piece of land. e.g. wheat and gram, or groundnut and sunflower.
• Inter-cropping is growing two or more crops simultaneously on the same field with some rows of one crop alternating with some rows of another, like soyabean and maize.
• Crop rotation is growing two or three different crops in a year on a piece of land. e.g. cereals alternating with legumes.
Crop protection management: Nurturing crop plants against damage by weeds, pests and disease is known as crop protection management.
Weeds are the unwanted plants competing with the crop plants for food, space and light, and finally reduce crop growth. Weeds can be removed by spraying herbicides or by removing them mechanically. e.g. Xanthium. Weeds can be controlled by timely sowing of crops, inter-cropping and crop rotation control the growth of weeds. Use of resistant varieties and summer ploughing also reduces the growth of weeds.
Pests attack the plants and reduce their yield. Most of the time insects are the pests which attack plants. They cut the stem and roots, they bore into the stem and fruits. They cut leaves. They suck the cell sap. Pests are controlled by pesticides.
Diseases in plants are caused by pathogens such as bacteria and fungi, and viruses, insects etc. These pathogens are transmitted through soil, water and air. Pathogens can be controlled by spraying herbicides, fungicides, insecticides etc.
Storage losses in crops are due to biotic factors like insects, rodents, fungi, mites and bacteria. Abiotic factors like inappropriate levels of moisture and temperature in the storage area also damage crops.
Grains should be cleaned and properly dried in the sunlight and shade before storage. Fumigation is the process by which grains are exposed to chemical fumes to get rid of pests.
Animal husbandry is the practice employed to increase the production of animal products by livestock. Animal husbandry includes feeding, breeding, and disease control of livestock animals.
Advantages of animal husbandry:
As animal husbandry is scientific management of farm animals, it serves many uses for human beings.
• It helps in enhancing milk production
• It increases egg production
• It increases meat production
• It increases fish production
• It helps in proper management of agricultural wastes.
A cattle farming is the practice of rearing cattle by providing facilities for raising livestock.
Livestock includes domestication of cows, buffaloes, sheep, goats, pigs etc. A cattle farming is carried out to raise cows and buffaloes as important livestock. The two major species of Indian cattle are Bosindicus, or cows, and Bosbubalis, or buffaloes.
Milch animals and drought animals
On basis of their utility, cattle are classified into two types namely milch animals and drought animals.
• Milch animals or dairy animals produce milk. Males of this type are not useful for working on farm.
• Draught animals are used for carrying out agricultural work like tilling, irrigation and carting. Cows belonging to this category are poor milk-yielding varieties.
Management practices for cattle farming
Management practices for cattle include cleaning, sheltering and feeding.
a) Cleaning involves periodic washing to get rid of dirt and loose hair.
b) Shelter facilities include well ventilated roof sheds which protect cattle from rain, cold and sun.
c) Feeding of cattle includes supply of uncontaminated and balanced diet. Animal feed are of two types namely roughage feed and concentrate feed.
• Roughage feed contains high fibre content and provides energy. It comprises fodder grasses, silage and legumes rich in fibre.
• Concentrate feed is a mixture of cereals, seeds and oilseed cake rich in protein content. This type of feed is easily digestible and it helps the animal in increasing body weight.
d) Cattle should be protected from diseases. Diseases in cattle are caused by both external and internal parasites. External parasites live on the skin and cause skin diseases. Internal parasites affect the stomach and intestinal parts. Certain preventive measures of diseases in animals are listed.
• Proper disposal of dead animals and animal wastes.
• Shelters should be clean, dry and well ventilated.
• Periodic visit of veterinary physician to check the animals.
• Hygienic management of animals and animal products.
e) Infectious diseases are caused by pathogens like bacteria, viruses and fungi. Sheds should be cleaned and disinfected regularly. Vaccination against various diseases should be provided to farm animals. Vaccination should be given against various diseases.
f) Milk production centres should be maintained for the animals which give birth to young ones. Milk production depends on duration of lactation period. Lactation period is the period following the birth of a calf during which milk is produced by the animal. Lactation period can be enhanced by administering certain hormonal injections.
g) Cross-breeding is done between foreign and local breeds of animals to facilitate the growth of animals with desired qualities. e.g. Foreign breed like Jersey cow, with long lactation period, is crossed with local breed like Red Sindhi cow, with high resistance to disease, to obtain offspring of desired qualities like long lactation period and high resistance to diseases.
Advantages of cross-breeding
Cross-breeding helps in the development of certain desired characteristics in animals.
• To increase milk production
• To increase resistance against diseases.
• To enhance the varieties with longer lactation period.
• To rely on less amount of quality feed.
Poultry farming is the practice of raising fowl for egg production and chicken meat. Fowls are used for producing eggs and broilers are used for producing meat.
Cross –breeding is common in poultry to develop new varieties with the desirable traits. e.g Indian breed Aseel is cross-bred with the foreign breed Leghorn.
Cross-breeding is used to develop offspring with desirable traits. The desirable traits include dwarf broilers that can be used as meat within a short period of time, higher number and better quality of chicks, and tolerance to high temperatures during summer.
Management practices for poultry farming are elucidated.
• Maintaining optimum temperature
• Providing hygienic housing conditions
• Providing a protein-rich diet with high levels of vitamin A and K, and
• Preventing and controlling pests and diseases.
Fish farming is also called as aquaculture. This is culturing of fish for commercial purposes. Fish is a cheap source of animal protein.
Types of fishery
a) Fin fishery and Shell fishery
Fish production involves fin fishery and shell fishery. Two main species of finned true fish are Catla and Rohu, and that of shellfish such as prawns and molluscs.
b) Capture fishery and culture fishery
Fish are obtained by capture fishing as an economic source for their meat.
• Capture fishing involves capturing of fish from sea water or fresh water. Culture fishing involves culturing the fish in small enclosures.
• Capture fishing is classified into marine fishery and inland fishery depending upon the resources used for fishing.
Culture fishery involves rearing of fish in small structures like wells.
• Fish farming can be done in the rice field where both grains and fish can be harvested from the farm.
• As feeding habits of fish differ from species to species, many varieties can be reared on the same farm. Composite fish farming is rearing of different varieties of fish in the same area. e.g. Composite fish farming includes Catla, the surface feeders, Rohu, feed in the middle zone of a pond, Mrigal and common carp, the bottom feeders, and grass carp, feeding on weeds. These species can co-exist in a single pond, and thus, increase the yield of fish from the pond.
c) Marine fishery and Inland fishery
Mariculture is the culture of fish in marine water.
• Marine fishery involves fishing in salt water regions.
• Some examples of marine fish are Pomphret, Tuna and Mackerel.
• Fish are captured by locating large schools of fish, in the open sea, with the help of satellites and echo-sounders.
• Marine fish of high economic value are farmed in seawater. Shellfish, such as prawns, mussels and oysters are also farmed in seawater. Oysters are cultivated for their pearls.
Inland fisheries involve fresh water canals, ponds, reservoirs, rivers from which fish are captured.
Estuaries are the regions where fresh water mixes with sea water. These are rich sources of fish.
Fish farming encounters the problem of lack of quality seed or eggs. Fish are bred in ponds by hormonal stimulation. Fish are injected with hormones that stimulate the production of eggs or seed. This ensures the supply of pure fish seed in desired quantities.
Distinguishing features between Capture fishery, Mariculture and Aquaculture
Fishes are caught from natural water resources.
Involves culturing and harvesting of fin fishes and shell fishes.
Involves culturing and harvesting of fish, prawns, crabs etc.
No seeding and rearing are required.
Fish seeds are introduced and fish are reared.
Fish and other organisms are seeded and reared.
This type of fishing is done both in marine and inland waters.
Fishing is done only in sea water.
Fishing is done both in fresh water and marine waters.
Beehives are enclosed structures in which honey bees live and raise their young.
• The practice of maintaining honey bee colonies in beehives is called bee-keeping or apiculture. Apiaries or bee farms are established for commercial production of honey.
• Bee-keeping is a cheap and popular agricultural enterprise.
• Honey produced in bee-hives is the source of honey used in food and medicines. Taste and the quality of the honey depend upon the flowers the bees visit for nectar collection.
• Wax obtained from these hives is used in ointments, polishes etc.
Types of bees
Apis Cerana indica is the local variety of bees available for honey production.
Apis dorsata and Apis Florae are other common varieties used for honey production.
An Italian bee variety, Apismellifera, is commonly used for commercial honey production. Bees of this species are known for high amount of honey collection.
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