12th Part
Q. What is meant by essential amino acids?
A. Our body is a biochemical factory that makes many compounds for its needs. However, there are limits to this, and what our body cannot make has to be provided by a suitable choice of food. Such compounds are called essential nutrients. Each one of the nutrients has many components. For example. most proteins are composed of twelve to twenty different amino acids. Ten of them cannot be manufactured by the body and have to be supplied through diet. They are called essential amino acids. The remaining are non-essential amino acids, in the sense that they can be made in the body from any protein food we take.
Animal proteins have all the essential amino acids and are called complete or high-quality proteins. They also have much higher digestibility. Plant proteins lack one or more essential amino acids and are called incomplete proteins. Their digestibility is about 60%. Thus the proteins which are obtained from a variety of plant sources can together provide all amino acids because what is missing in one plant protein may be compensated by another.
Q. Justify that 'livestock are our mainstay for providing agricultural operations and transport'.
A. Livestock provides us milk, meat, eggs, wool and skins, and other by-products that are necessary to human beings. All these products contribute about Rs. 2000 crore a year to our national economy. Practically every family in the village is involved with domestic animals, which are an important source of livelihood and employment to the villagers. Machines provide marginal power because of the small and scattered farms in our villages, hence cattle’s are used in agricultural operations and transport by marginal and small farmers. India today has about 185 million cattle which are being employed in different works besides providing milk, meat, wool, eggs, etc. Besides cattle dung is also used as manure in organic farming. Therefore it is correct to state that livestock is our mainstay for providing agricultural operations and transport' in rural India.
Q. Vitamins
A. Vitamins can be obtained from plant and animal foods. Vitamins are required in small amounts but their prolonged deficiency in food results in various diseases. In order to correct this situation, sometimes vitamins have to be given as tonics or medicine. Vitamins are not a source of energy themselves but they help in the release of energy from carbohydrates, and fats. Therefore, food must contain the required amounts of vitamins. There are various types of vitamins. A particular vitamin or a group of two or more vitamins, protect the health and assist in the proper functioning of different organs of our body. Each vitamin has a specific function and cannot substitute for another.
# Vitamin A is needed for healthy eyes, smooth skin, and glossy hair. Many children go blind in our country because of vitamin A deficiency. This could be easily prevented, because foods containing vitamin A, like carrots and green vegetables, are easily available.
# Sometimes children or even adults complain of lack of appetite. They never seem to be hungry for meals. This is due to the deficiency of vitamin B group, which leads to undernutrition and retardation of growth.
# Vitamin C is present in fresh fruits and vegetables, especially in citrus fruits and guava. It is essential for the health of the mucous membrane which lines our mouth, nose, and inner organs. It helps in building resistance against infections like common cold.
# Vitamin D which is present in eggs, milk, butter, etc., helps in proper formation of bones. Its deficiency leads to weak bones or physical deformities like bow legs in children. This is the only vitamin which our body can make in the skin, by the action of sunlight which is plenty in India and costs nothing. Vitamin D is also called "sunshine vitamin".
# Vitamin K Prevents bleeding in wounds by clotting of blood
Q. Comment briefly on the advancements made in Indian agriculture in :
(a) Arid zones
(b) Hilly regions.
© Dry land
A. Because of the increasing demand for food, the regions which were once considered difficult are now being brought under cultivation. In such regions, some of the factors such as moisture, the right temperature, etc., required for the usual crops, are not available. Therefore, plants that could withstand these difficult conditions are grown here, and similarly, the hardy animals are reared in these areas.
Arid Zones - The chief arid areas of our country are confined to Rajasthan, Gujarat, Haryana, Karnataka, and Ladakh.
In Ladakh aridity and low temperature limit the agricultural season to about five months in a year. Therefore, crops that require a short period to mature and can withstand severe cold are grown. These are some cereals, oilseeds and fodder crops. Amongst animals, the Pashmina goats, whose hair are in great demand for producing shawls and apparel, can be profitably reared in Ladakh.
In the hot desert regions of Rajasthan, and dry areas of Gujarat and Haryana the rainfall is highly unpredictable. In these arid zones, fruit-trees like ber and pomegranate and fuel-wood yielding trees like Acacia (Kikar), Prosopis (Mosquite) and Eucalyptus (Safeda) are grown. In such areas, large scale planting of shelter-belts will minimize soil erosion caused by wind. It will also help in the establishment of pastures and grazing lands. Later on, this land can be used for growing crops like pearl millet and mungbean.
Drylands
Drylands produce about 42% of our food. They supply us millets and pulses, as well as cotton and groundnut, on which a large proportion of our agro-based industry is dependent. Drylands constitute about 74% of our cultivated lands. These are entirely rain-dependent and crop fortunes are closely linked to the vagaries of the monsoon. In our country, which is situated in the monsoon belt of south-east Asia, the rainfall is neither uniform nor is evenly distributed throughout the year. In drylands with red soil, deep ploughing helps in conserving water. In black soils, sowing two crops at a time is possible with surface drainage and good water management. Leaves and crop residues, when mixed with soil improve its texture, and water holding capacity.
Hills
Based on a study of the slope and depth of the soil, and availability of water, scientists have devised an interesting agricultural system that requires low inputs and puts the land to most productive use, without disturbing the ecosystem. Under this system, the upper reaches of the hills are devoted to forestry. The next zone is used for growing fruit trees, perennial fodder grass and legumes. The roots of legumes fix nitrogen and improve the soil quality. In the third zone, a mix of crops are raised on terraces which are constructed with low-cost implements. Earthen dams are constructed with locally available material. These collect enough water to be utilized for irrigation and fish culture.
Q. What is the ideal way of pest management?
A. Several kinds of insects, diseases, weeds, rodents, and birds cause immense damage to crops both in the field and in storage. To control pests problem, it is necessary to adopt integrated pest management that keeps the damage due to pests at the barest minimum. Integrated pest management will be effective if we grow pest-resistant varieties of crops in regions where the incidence of pests is severe. It must be ensured that crops grown one after another do not have common pests. Instead of chemicals for pest control, use biological organisms that attack the pest. Pesticides should only be used when the pest population has reached its threshold value, and take co-ordinated community action on pest control not just in adjoining fields but the whole village or block.
Excessive doses of pesticides shouldn’t be used as it leaves harmful residues which find their way into the human body either directly from the consumed agricultural produce or through the milk of animals that feed on plants. It is essential, therefore, that pesticides are applied only in recommended doses that are harmless.
Q. What is biotechnology? Describe its main techniques. List any two applications each in the fields of agriculture and medicine.
A. Biotechnology also offers a wide scope for the improvement of our animal breeds. Using the embryo-transfer technology we can produce pedigree animals of high quality on a mass scale within a short time period. For this purpose, a cow of a good breed is induced to produce many eggs through hormonal treatment. After they are fertilized, the embryos are taken and planted in healthy cows, known as surrogate mothers. Ultimately we can get many calves of a superior breed in a short period of time.
Q. There is a mismatch between man's scientific ability to produce and social incapacity to utilize'. Analyze the statement.
A. i) Though we have the scientific and technological know-how to produce what the country needs, but most of our people are poor and cannot make use of it. A large number of people do not have enough money to buy even food.
ii) About 22.7% of our people are agricultural laborers and have no land, and they have a hand to mouth existence.
iii) Facilities for marketing, storage, transport. distribution, processing and customer service are beyond the capacity of individual farmers more particularly the ones with small land holdings.
Q. In what ways can biotechnology play an important part in agriculture?
A. Biotechnology can help us tremendously in the improved production of varieties of plants and animals. New techniques such as tissue culture, not only enable us to grow novel plants but also enables one to mass-produce plants in a shorter time without going through the steps of flowering, production of seeds, and their germination. By the application of principles of genetic engineering, plants can be produced with desired qualities. If we apply biotechnology to raise orchards, the fruits produced will be of uniform size, shape, weight, etc. This makes their harvesting, storage, packing, transport, canning, and processing easier. The embryo transfer technology would enable us to produce many copies of good animal breeds faster.
Q. Mention in points, the salient problems associated with modem agriculture
A. i) Sources of energy presently in use put considerable pressure on non-renewable resources. Besides being costly and polluting they are feared to run out in the near future.
ii) Too much mechanization would no doubt increase production, but would also result in unemployment and poverty, hence people would lack purchasing power to buy food.
iii) Chemical fertilizers and pesticides used in agriculture have long term harmful effects not only on human beings but also on the environment.
iv) Many of the modem technologies can be applied to large fields and are expensive. But most of our farmers are small landholders and therefore they cannot benefit from these recent developments.
v) In developing countries like ours, even a 10% increase in production poses the problem of storage, a glut in the market and distress sale. The problem becomes acute if these are perishable commodities.
Q. What are the salient features of mixed, and relay-cropping systems?
A. Since the food requirement in our country is growing but the cultivable land is limited, hence it becomes necessary to grow two or more crops in a year from the same piece of land.
In a relay cropping system, a crop is sown before its preceding crop is harvested. The last irrigation was given to a crop also serves as pre-sowing irrigation to the next crop. This results in the saving of water also.
In mixed cropping, compatible crops like chickpea and mustard are sown in parallel rows with wheat. Pigeonpea, mungbean, groundnut, soybean, and cowpea can be grown in between rows of either sorghum, or maize, or sugarcane or cotton. Such intercropping systems have high production potential and generate additional employment opportunities.
Q. Which two factors determine the energy requirement of a person in a day?
A. The energy requirement of an individual depends mainly upon:
i) internal or basic processes of the body which is also called Basal Metabolic Rate (BMR) and
ii) physical activity carried out by a person in a day.
The greater part of the energy is spent for internal activities or for Basal Metabolism, which is influenced by various factors like the surface area of the body, sex, age, sleep, body temperature, level of hormones, etc. For example, the BMR for different persons and states is as follows:
Tall thin person > Short thin person,
Muscular person > Short fat person,
infant > Adolescent
Male > Female
Awake > Sleep
Young person'> Old person
During fever > Normal health
Cold climate > Hot climate
Physical activities depend upon the kind of work done by an individual, whether it is light, moderate, or heavy work. The requirement of energy for physical activities is generally lower than BMR, except in case of persons engaged in very hard physical work like stone-cutting, running, etc.
Q. What do you mean by alternate food resources? Briefly discuss the advancements our country has made in its production.
A. Alternate food resources mean livestock which is alternate of agriculture. It includes cattle, pig, sheep, goat, fish, and poultry.
Milk - The country, today, has less than half a million good dairy cows and about 25 million buffaloes that give a medium yield of 1,000 to 1,500 litres per lactation. High-yielding breeds of cows such as the Holstein-Friesian, Brown Swiss and Red Dane averaging 5,000 to 6,000 litres per lactation and Jersey cows averaging 4,000 litres per lactation, were imported and used in crossbreeding programmes. Their progenies yield, on average, about 3,000 litres of milk.
Poultry - Because of intensive research on poultry nutrition, we have been able to reduce the feed requirement from 6 kg to about 2.2 kg for the production of one kilogram of live weight broiler or one dozen eggs. Today, we are self-sufficient in the production of all medicines required for poultry health. Intensive research work has enabled to evolve many good, high-yielding strains of broilers.
Fisheries - Our present catch from the seas is about 1.2 million tonnes and India ranked 8th in fish production. Sophisticated techniques such as Remote-sensing and Satellite imageries are now being used to locate concentrations of fish. Improved techniques have been devised for the culture of mussels, pearls, oysters, shrimps, lobsters, and seaweed. Mechanized Fishing Boats and vessels have also been introduced, together with facilities for cold storage and canning. In inland fisheries, composite fish culture is now followed to increase productivity. Here, ponds are stocked with different types of fish that feed at the bottom, middle level and the surface of the pond, the fish do not compete with each other, but utilize the food resources throughout the pond. Such a practice is also known as a composite fish culture.
Eggs - The production of eggs has also gone up tremendously recently. Also, now more eggs can be obtained by less of feed inputs to the poultry.
Q. Give the different types of agro techniques used for increasing food production in our country.
A. Different types of agro techniques used for increasing food production in our country are-
Cropping Systems - Since cultivable land is limited, the only way to meet our growing food needs is by growing two or more crops in a year from the same piece of land. In a relay cropping system, a crop is sown before its preceding crop is harvested. The last irrigation was given to a crop also serves as pre-sowing irrigation to the next crop. This results in the saving of water. In mixed cropping, compatible crops like chickpea and mustard are sown in parallel rows with wheat. Pigeonpea, mungbean, groundnut, soybean, and cowpea can be grown in between rows of either sorghum, or maize, or sugarcane or cotton. Such intercropping systems have a high production potential.
The input of Fertilisers -
Nitrogen, phosphorus, and potassium are the major nutrients that plants require. In addition, zinc, iron, manganese, boron, molybdenum, and cobalt are also needed by plants in small quantities for healthy growth. Deficiency of any of these elements reduces yields, even when all other nutrients are available in adequate amounts. But, the excessive presence of some of these nutrients may prove toxic to plants. The nutrient needs vary not only from crop to crop but also from soil to soil. It is essential, therefore, that the soil is tested and the required amounts of nutrients supplied according to the needs of the crops. Generalized application of commercially available fertilizer mixtures such as the one having nitrogen, phosphorus, and potassium in the ratio of 120:60:40, is often quite wasteful and even reduce yields.
Crop Protection
Several kinds of insects, diseases, weeds, rodents, and birds cause immense damage to crops both in the field and in storage. Pests have been there long before man came into existence. It is not possible to eliminate them entirely, either by developing varieties that resist attacks of pests or by using potent pesticides. It is important to practice integrated pest management that keeps the damage due to pests at the barest minimum. Integrated pest management will be effective if we grow resistant varieties in regions where incidence of pests is severe, ensure that crops grown one after another do not have common pests, instead of chemicals for pest control use biological organisms that attack the pest, apply pesticides only when the pest population has reached its threshold value, and take co-ordinated community action on pest control in adjoining fields over the whole village or block.
Q. Give any four examples of plantation crops.
A. Tea, coffee, cocoa, rubber, coconut, areca nut, cashew, cardamom, black pepper, and related spices are grown on a plantation scale, and their product has a good demand both within and outside our country. Our scientists have developed technologies for multi-tier cropping to make more profitable use of the available space in plantations and orchards. For example, pepper can be twined along the trunks of coconut and areca nut trees, and in the space between areca nut trees, pineapple, fodder legumes and grasses can be planted. Such multi-tier cropping increases the productivity per unit area per unit time.
