Category : 9th Class
Improvement in Food Resources
Chapter Overview
We know that all living organisms need food to get energy and nutrients like protein, carbohydrates, fats, vitamins and minerals. All these nutrients are required for maintenance of our body, development, growth, proper health and sustenance. These nutrients are provided by both plants and animals. It means we are directly or indirectly dependent on agriculture and animal husbandry. Hence the improvement of agriculture as well as of animals has always been
Inevitable since time immemorial. But even then, it is natural to think over some burning questions Like, Can the current levels of production be sufficient for us? Why it is necessary to improve the plants and animals? How can we meet with the current demands of production?
The reasons of all these questions lie in the following facts:
The first mode of increasing the farming land, is not easily possible in our thickly populated country. Hence, the second point is the only best option with us.
|
Green revolution |
Cereal grain production |
|
Blue revolution |
Fish production |
|
White revolution |
Milk production |
|
Yellow revolution |
Mustard oil production |
|
Golden revolution |
Pulse production |
|
Silver revolution |
Egg production |
Scientific or Sustainable Practices: The majority of our population is dependent on agriculture for their livelihood. Besides, people should have enough money to purchase food.
Hence, it is necessary to increase the income of farmers so that the problem of hunger and malnutrition could be avoided. For this some scientific practices should be taken so that better yields may be obtained from the farm lands. Sustainable agriculture involves practices such as organic farming, biological and natural control of pests, mixed farming, inter cropping which combine agriculture with live stock or poultry fisheries, beekeeping etc.
Crops are plants which are cultivated by humans for food, fodder, fibre, flowers, timber etc. There are about 2000 plant species which are cultivated for eating purpouse.
Types of crops: On the basis of usable parts of the plants, crops are categorised as following heads-
(a) Cereals: They are rich source of carbohydrates. They include crops such as wheat, barley, rice, maize, sorghum, etc.
(b) Pulses: They are excellent source of proteins. They are obtained from leguminous plants such as gram (chana), pea (matar), black gram (urad), green gram (moong), pigeon pea (arhar or tuar), lentil (massoor) etc.
(c) Oil seed crops: We get fat from oil seeds such as soyabean, groundnut, sesame, mustard, linseed and sunflower. They are source of vegetable oil and fatty acids. These seeds are typically high in unsaturated fats and when consumed in moderation are regarded as healthy foods. Coconut and palm oil are other sources of cooking medium. Castor oil is not edible oil. It is mainly used as a lubricant or negative, in the manufacturing of transparent soaps, inks, paints, phenyls, hair fixers, etc.
Wheat Maize
Pea Chicken pea
Soyabean Ground net
Fig. 3.1
(d) Nuts or Dry fruits: Nuts or dry fruits are rich in proteins and fatty acids. They are considered as quality food items and include almond, walnut, cashew nut, pistachio, raisin, fig, dried apricot, and coconut, peanut, date etc.
2 Fruit Crops: Usually fruits are ripe ovaries of plants. They are good source of minerals, vitamins carbohydrates, fats and roughage. They include, banana, apple, mango, orange, guava, papaya, watermelon, muskmelon, pear apricot, grapes, pomegranate dates, custard apple etc.
(a) Roots: Roots of some plants are eaten as vegetables such as carrot, radish, sweet potato, sugar beet etc.
(b) Stems: of some plants are eaten as vegetables such as potato, onion, garlic, Ginger, etc. Stems of sugarcane are used for making of sugar and jiggery.
(c) Leafy vegetables: These include leaves of lettuce, cabbage, spinach, mustard, radish, methi, pigweed (bathua), chaplain, curry-leaf etc. These are good source of vitamins and minerals.
Fig. 3.2
(d) Inflorescence vegetables: These include cauliflower, broccoli etc. These are also a good source of vitamins and minerals.
(e) Fruit vegetables: These include most vegetables such as urinal, pumpkin, tomato, lady's finger, jack fruit, bitter gourd, bottle gourd, cluster bean, cucumber, capsicum demand, etc.
4 Spices: Certain parts of some plants are used to enhance the palatabihty of food. They include black pepper, chili, turmeric, cumin, cardamom, fennel, fenugreek, nutmeg, cinnamon, dried ginger, clove, sesame, etc.
On the basis of seasonal variations, the crops in our country can be classified into-
Improvement in yields: Presently, evolution of certain strains of many crops has made it possible to grow a crop in any season or throughout the year like tomato, sorghum, maize etc.
Following three scientific approaches are adopted in our country to obtain high yields from our agriculture farms:
Ever since human gave up his nomadic life and settled down in a place to start social and cultural life, he began cultivating crops and bringing about certain changes in the wild varieties for his benefit. Nearly all the present day crop plants were developed by prehistoric man by bringing about gradual alternations in their wild ancestral species. Now a day crop plants are, therefore, the products of their careful artificial selection and plant breeding practices. Plant breeders select plant varieties with desired characters and cross them. The developed progenies combine the attributes of both parents. These varieties are multiplied and supplied to farmers.
The science of improvement in genotypes of plants by improving their genetic potentialities is called plant breeding.
Aims and objections of plant breeding
Some of the important factors for which variety improvement is done are listed below:
Plant breeders therefore, develop resistant varieties to control these stresses. For example MUW318 is a high yielding variety of wheat which is released for cultivation in non-traditional areas such as Nilgiri and is palani hills and resistant to all the rusts.
Do You Know
Green Revolution in India
Increase in food production by improving crop varieties and cultivation practices during.
The year 1960s and 70s is termed as green revolution. The 1970 Nobel laureate American scientist Dr. N. E. Borlaug was the person behind triple dwarf Mexican wheat varieties.
Their colour was changed to Indian liking through gamma irradiation by M.S. Swaminathan, Father of Green Revolution in India.
Green revolution has made our country self-sufficient in food production, increased the buffer stock of food grains and improved the economic conditions of our farmers as well as provided employment avenues to large number of people.
Plant Breeding Techniques
Crop variety improvement is manipulation of crop plants for increasing their yield, improving quality, suitability to varied conditions and resistance to biotic and abiotic stresses. Genetic manipulation is incorporation of new genes for various characteristics from other genotypes into the crop variety so as to bring about desired changes. Some commonly used plant breeding strategies for improvement of varieties are hybridisation, mutation, breeding, polyploidy and DNA recombination technology. Plant breeding is the science and art of improving the heredity of plants in relation to their economic use. There are four main plant breeding techniques. They are.
For example, crops such as coffee, tea, potato, tobacco, ground nut, papaya, etc. have been introduced in India from the other parts of the world. Plant introduction is a quick method to bring about improvement with minimum effort and cost.
There are following two patterns of selection:
(a) Mass selection: In this pattern, seeds from a number of similar plants having the desired characters are mixed and sown to grow the new off springs. Off springs with undesirable characters are eliminated and the process is continued with the remaining progeny in the same manner until the desired improvement is achieved. Apples, grapes, pear, radish, onion, maize etc. have been improved by this pattern.
(b) Pure-line selection: In this pattern, seeds from a single plant having the desirable characters are sown in separate rows to produce the progeny. Desired plants are again selected from the progeny and the process is continued for several generations. The inferior plants are eliminated in each generation. Wheat variety such as Kalyan Sona-227 and PV-18 have been developed by this pattern. Selection by human beings is also called artificial selection. Artificial selection operating over long time spans can give rise to varieties strikingly different from starting generation. For example, cabbage, cauliflower, broccoli, and many other varieties have been produced through artificial selection from wild cabbage.
3. Hybridization: A technique of plant breeding in which two plants having the desired characters are crossed and develop seeds is called hybridisation. Seeds produced by hybridization are called hybrid. During hybridisation one plant is considered as male. The pollen grains of this plant are collected for pollination. The other plant is considered as female. The stigma of female plant is dusted with the pollen grains of male plant. After pollination, the fusion of desired male and female gametes results in the formation of a hybrid embryo having the characters of both the parent plants. The hybrid seeds of this plant are collected and grown in the field.
Fig. 4.1: Method of Cross breeding or hybridization
There are several types of hybridisations. Some are listed below:
(i) Intervarietal hybridisation: i.e. between two plants belonging to different varieties.
(ii) Intravarietal hybridisation: i.e. between the two plants belonging to same variety.
(iii) Interspecific hybridisation: i.e. between the different species of the same genus.
(iv) Intergeneric hybridisation: i.e. between two different genera.
(GM crops).
The newly formed variety of crop should be able to produce better yields under different conditions prevailing in different regions. The farmers should be provided with good quality seeds so that better seeds with desired characteristics may be multiplied.
Bt cotton is a genetically modified crop which carries bacterial genes that protect plants from insects. Bt stands for the bacterium Bacillus thuringiensis whose genes are used by transgenic crop such as cotton, rice, maize, potato, tomato, brinjal, cabbage, cauliflower, etc to get protection from their insect pests.
Fig. 4.2: Method followed for the production of genetically modified (GM) crops
Mutation breeding: Mutations are sudden inheritable variations. They are produced at random through a number of chemical and physical agents called Mutagens. NE Borlaug (1963) developed triple dwarf Mexican varieties of wheat through incorporation of mutation by selective hybridisation. They were, however, red grained. The same were converted into amber grained form (e.g. Pusa Lerma, Sharbati Sonara) through mutation carried out by gamma irradiation.
Polyploidy: It is increasing the sets of chromosome. Polyploids are generally more robust with higher yields, e.g. potato.
India is an agriculture based country. In India, agriculture engages about 70% of people and accounts for 40% of the Gross National Product (GNP). Different types of farming practices are being carried out by different types of farmers (such as small, big, marginal, traditional and progressive). These methods depend upon size of the land holding, education and financial conditions of the farmers. The productions practices include "no cost" production, "low cost" production; and '"high cost" production. High cost production is based on improved high yielding varieties, improved farming practices, modern technology, largest agricultural tools, machines and implements. Crop production management is controlling the various aspects of crop production so as to obtain the maximum and the best yield. It has three components i.e. nutrient management, irrigation and cropping pattern.
5.1 Nutrient Management
The plants require nutrients for building up their structures and maintaining their body functions. The plants require inorganic elements, which they chiefly obtain from the soil, while some nutrients are supplied to plants by air and water. The major elements supplied by air are Cand\[{{O}_{2}}\]. The hydrogen comes mainly from soil water. Soil is the main source to supply rest of essential elements to plants. There are about 40 elements found in the plant ash, but only 16 of those elements are essential for plant growth and development. Hence these 16 elements are called essential plant nutrients.
Out of 16 nutrient elements required by plants, carbon and oxygen are supplied by air, hydrogen is supplied by water and remaining 13 elements are supplied by soil. Six of these elements are required in larger amounts. They are called macro-nutrients. The elements categorised as macro nutrients are-Nitrogen (N), phosphorus (P), Potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S). The remaining seven elements, required in trace or micro amounts, are called micro nutrients. They are Iron (Fe) Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), Molybdenum (Mo), and Chlorine (Cl).
Table 5.2: Nutrients required by plants
|
Source |
Nutrients |
Type of nutrients |
|
1. Air |
Carbon (C), Oxygen (O) |
Macronutrient (2) |
|
2. Water |
Hydrogen (H) |
Macronutrient (1) |
|
3. Soil |
Nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur, Iron, mangancese, Boron, Zinc, Copper, Molybdenum and chlorine. |
Micronutrient (7) |
Mineral Replenishment: All the 13 essential mineral elements must be present in the soil when the plants grow. Crop plants regularly withdraw minerals from soil. Unless and until minerals are replenished at regular intervals, the plants will develop disorders in structure, growth, reproduction, functioning and susceptibility to disease. Mineral replenishment is done through addition of manures and fertilizers.
Manures: Manures are partially decomposed organic substances of biological origin added to the soil to increase the fertility of soil and productivity of crop. They contain almost all the essential elements required by plants. The manures are of the following four types:
(i) Farm yard manure (FYM)
(ii) Compost
(iii) Green manure
(iv) Vermicompost
(i) Farm yard manure (FYM): It is the decomposed mixture of animal excreta (dung), urine, litter (i.e. bedding material used in night under catties) and left over organic matter such as roughage, or fodder and crop residues. These waste materials are collected daily from the cattle shed and stored in a pit for the decomposition by the microorganisms (i.e. bacteria, fungi etc). These microorganisms decompose complex organic debris into a dark amorphous substance (humus and degradation products which are easily assimilated by plants. FYM contains nitrogen, phosphorus and potassium. A well decomposed FYM contains about 0-5% potassium monoxide\[({{K}_{2}}O)\].
(ii) Compost: It is a kind of manure which is prepared by degrading the vegetable waste, garbage; sewage, sludge, animal refuse, domestic waste, straw, eradicated weeds etc. The mixture is placed in a trench of suitable size, i.e.4 to 5m long, 1-5 to l-8m broad and 1*0 to l*8m deep. It may be moistened A thin layer of soil may be placed over the mixture, and in such a way second and third layer of refuse mixure are made in trench. Finally it is covered by a thin layer of soil to prevent breeding of flies and other disease spreading animals. Compost is ready within 3-6 months. It is richer in mineral as compared to farm yard manure, (i.e. 1.4%N), 1.0% \[{{P}_{2}}{{O}_{5}},\]114% (W)\[({{K}_{2}}O)\].
Fig. 5.3
(iii) Vermicompost: Vermicompost is a kind of manure, rich in organic matter and nutrients, which is prepared from organic wastes of plant and animals origin by the activity of earthworms.
The earth worms promote soil aeration crush and mix soil particles and convert the nutrients into simpler forms that is why they are popularly known as "friend of farmers". They are very well known as "Nature’s ploughman". They act as scavenger of pathogenic bacteria and promote the activities of beneficial bacteria in the soil.
(iv) Green manure: It is a kind of manure formed inside soil from young green crop plants ploughed back into soil. The green manure crops are generally quick growing legume crops which are mulched by plugging back into field in tender stage (about 6-8 weeks) only, usually at the time of flowering. These crops are commonly decomposed in about 1.2 months when the next crop can be sown. A green manure crop supplies nitrogen, phosphorus and organic matter for improving hydration, aeration and crumb structure of soil. It provides protection against erosion and leaching.
Some example of green manure crops are Sesbania aculeata (Dhaincha), Crotalariajuncea (Sannhemp), Dolichos uniforms (Horse gram), Cyamopsis tetragonoloba (cluster bean), Lense esculenta (masur), Vigna sinensis (Cow pea).
The crops which require high nutrient input are raised in the green manured field, e.g. maize, rice, wheat, cotton etc.
Advantages of using manures:
(i) Manure provides a lot of organic matter (humus) to the soil which increases water holding capacity, drainage and aeration.
(ii) Manure also improves the physical characteristics of the soil.
(iii) Manure enriches the soil with nutrients.
(iv) It provides food for soil organisms like bacteria, earthworm.
(v) By using biological wastes as a manure, we recycle the wastes and protect our environment from chemicals (fertilizers).
It contains substances that stimulate plant growth and seed germination.
Limitations of using manures:
(i) In manures nutrient contents are low.
(ii) A manure releases minerals slowly.
(iii) Manure is quite bulky. It is needed in very large quantity.
(iv) Being bulky it cannot be transported over long distances.
(v) Manure cannot be stored beyond a period of 1-2 months.
(vi) Manure cannot meet soil deficiency of a particular mineral as it is not nutrient specific.
Fertilizers: Fetilizers are commercially prepared synthetic chemical substances added to the soil to overcome the deficiency of mineral nutrients and to maintain the fertility of soil.
They enhance the vegetative growth to make the plants healthy. Fertilizers are generally used by rich farmers to ensure higher crop yield.
A complete fertilizer is the one which contains all the three critical elements or minerals.
Critical minerals are the ones which become commonly deficient, viz Nitrogen, Phosphorus, Potassium. Depending upon the critical element present, fertilizers are of four main types-
Advantages of fertilizers:
(i) Fertilizers are nutrient specific, so they supply specific nutrient to the soil.
(ii) They are compact, so they are easy to store and transport.
(iii) They are required in small amount.
(iv) They are readily absorbed by the plants because they are soluble in water.
(v) They are available throughout the year at all places.
Application of fertilizers: Fertilizers should be applied scientifically in terms of proper dose and timing with pre and post application precautions for their complete utilization. They can be used before sowing, during irrigation or sprayed on standing crops. Fertilizers should not be applied directly to soil if the crop is standing. Fertilizers should not get washed away due to excessive irrigation or rain. Fertilizers in excess of crop absorption will lead to soil degradation and pollution of both surface and ground water.
Disadvantages of fertilizers:
Fertilizers are factory made chemicals. In excess, they cause-
(i) Chemically change the soil making it either too alkaline or too acidic.
(ii) Water pollution in rivers and lakes due to eutrophication which makes the water unfit for human consumption and even kills the aquatic animals.
(iii) They are quite expensive. They push the cost of crop production.
(iv) They harm soil microorganisms.
(v) Non-replenishment of organic matter destroys the crumb structure of soil, affecting adversely both hydration and aeration.
Biofertilizers: Organisms which are used to enrich the soil with nutrients called biofertilizers.
They are used for the specific crop plants such as pulses, oil seed and rice. They are renewable and non-pollutant sources of plant nutrients such as nitrogen. Biofertilizers are not alternative to chemical fertilizers but can play a supplementary role is supplying nitrogen to specific crops under specific soil conditions. Nitrogen fixing micro-organisms (symbiotic and non-symbiotic) and phosphate-soluble microorganisms are the main type of biofertilizers that are being used in our country. Two biofertilizers, namely Rhizobium cultures (symbiotic bacteria) and blue green algae (Nostoc and Anabaena) have gained popularity amongst farmers cultivating pulses, legumes, oil seeds and wet land rice.
Mycorrhiza: They are symbiotic association of certain fungi with roots of higher plants.
Fungal component of mycorrhiza increases water and nutrient uptake by plants and increases growth, vigour and yield of the crop.
Organic farming: It is a kind of farming system in which the harmful chemicals are either not used or used only in minimum amounts. There are several methods of organic farming which use farm yard manure, biofertilizers, vermicompost, green manure, biocompost, biopesticides etc. In organic farming due to little or no use of chemical fertilizers, pesticides, and herbicides, there is no pollution of soil, water or air. Organic wastes are recycled in the form of manure. Biofertilizers include the use of nitrogen fixing organisms and mineral soluble organisms. Biopesticides are organisms or their extract which repel or kill weeds, insects and other pests, e.g. azadiractin (Neem or margosa), Pyrethrum (Chrysanthemum), thurioside (Bacillus thuringiensis, bacterium). Neem leaves have been used in grain storage as biopesticide. Healthy crorpping systems include mixed cropping, inter cropping and crop rotation. These cropping patterns help in controlling insect, pests and weeds.
Advantages of organic farming:
(i) It is eco-friendly and does not cause pollution of any component of our environment.
(ii) In organic farming, farm wastes are recycled.
(iii) The food obtained from organic farming is free from pesticides and toxic chemicals.
(iv) Organic farming maintains soil texture.
(v) The cropping systems of organic farming keep insect, pests and weeds under control.
5.4 Tribulation
All crops obtain water from soil. Water is a basic component for all types of agriculture. A soil which is the source of infinite life becomes barren without water. Soil obtains water from rain fall or snow fall. However sufficient rain is not always there. Therefore, soil is not able to supply required amount of water to crops. The extra water required by crops is met through irrigation.
The process of supplying water to crops through human efforts by means of tube wells, wells, canals, reservoirs etc. is called irrigation. Our country has quite sufficient kinds of water resources including monsoon rains, water sheds and ground water. The average rain fall is about 120 cm. In India, there are 12 major river basins and 8 composite river basins. Ground water also contributes significantly to our total water resources. This is replenished by rainfall. However, only 55% of our cropped area is either partly irrigated (about 25%) or is under assured irrigation (about 30%).
Remaining about 45% of our cropped area is unirrigated and is dependent on rain for the cultivation of crops. It is known as rain fed agriculture. The success of rain fed agriculture depends upon timely and sufficient rain during most of the growing season. Scarcity and irregular distribution of rain can cause drought. Here poor rains would result in crop failure. However, plant breeders have produced some crop varieties which can grow in rain fed areas and tolerate drought conditions.
Even then they are unable to compete with varieties growing in irrigated areas as water is essential for optimum growth and yield. Government and private bodies are engaged in water management by doing rain water harvesting and water shed management.
Advantages of irrigation: Irrigation is one of the oldest agricultural techniques practiced by farmers. It has many advantages over simple reliance on rain water supplies-
Irrigation system: Intermittent drought and poor rainfall pose a serious threat to rain fed farming areas. These need supply of water from external sources. Under such conditions, irrigation system is adapted to supply water from different water resources. Some common irrigation systems are as follows-
(a) Dug wells: These are open wells where water gets collected from water bearing strata.
They are owned privately by the farmers. From these wells water is lifted by mechanical means e.g., bullock operated device. Dug wells do not have long life and soon become dry whenever water table goes down.
(b) Tube wells: A tube well can tap water from the deeper strata. From these wells water is lifted by diesel or electricity run pumps. Deep bore tube wells can supply water continuously for many years.
Fig. 5.5: Tube well
They are usually constructed below the higher elevation of the catchment area. In the tanks, outflows are regulated according to the water availability.
Do You Know
Water Augmentation: Water availability for irrigation can be assured by augmenting ground water. It is carried by following two methods:
4.3 Cropping Pattern
In order to get maximum benifit from the piece of land, operated as a unit for the production of agricultural products, different patterns of growing crops are followed. These are-
Mixed cropping or multiple cropping
Practice of cultivating two or more crops simultaneously on the same piece of land is called mixed cropping or multiple cropping. In this farming system, farmers mix the seeds of two or more crops and then sow them in the field. This type of farming is an insurance against crop failure due to adverse weather and attack of pathogens and pests The different crops to be grown together are also chosen that they do not have common pest and pathogens or similar requirements of water and minerals. Rather the products and waste materials from one crop stimulate the growth of the other crop.
In our country, the following combination of crops are used for mixed cropping:
\[\to \]Wheat + gram / musturd
\[\to \]Ground nut + sunflower / gram
\[\to \]Cotton + ground nut / moong bean
\[\to \]Maize + black gram
\[\to \]Pigeon pea + soyabean / sorghum / moong bean
\[\to \]Barley + gram
Criteria for selection of crops: The following criteria are taken into consideration while selecting crops for mixed cropping:
(i) Nutrient demand: If one of the crop plant requires higher amount of nutrients, the other should require lesser amount of nutrient.
(ii) Root patterns: Both the crops should not have same root pattern. One crop should have deep penetrating roots whereas other should have shallow roots.
(ii) Water requirement: Both the crop plants should have different water requirements. If one of the crops requires higher amount of water, the other should require lesser amount of water.
(iv) Growth habit: If one plant is tall, the other should be dwarf. They should have different structure of leaves, stems, branching pattern of stem and flowers.
(v) Duration of crops: Both the crops should have different maturation period. If one is short duration crop, the other should be of long duration.
Advantages of mixed cropping:
(i) It reduces risk of crop failure.
(ii) It helps in optimum utilization of the soil.
(iii) It helps the farmer to earn more.
(iv) Due to different nutrient requirements of different crops, it avoids exhaustion of soil nutrients.
(v) Growth of leguminous crops improves soil fertility and reduces the requirement of fertilizers.
(vi) It helps to increase the yield due to complementary effect of one crop on the other, for .example, legume crop and cereal crop. Legume crop adds nitrogen to the soil which increases the total yield.
Disadvantage of mixed cropping:
(i) Cultivators face difficulty in applying fertilizers to individual crops.
(ii) They face difficulty in spraying pesticides or herbicides on individual crops.
(iii) Harvesting and threshing of crops separately is not easy, because seeds of the two crops are mixed and then sown.
Inter-cropping
Practice of cultivating two or more crops simple timeously in different rows or strips on the same piece of land is called inter-cropping. In this method crops are grown in a set pattern. For example, a few rows of soyabean alternate with a few rows of maize in the total field area. The crops selected for such type of pattern should have different types of nutritional requirements.
Following crop combinations are usually grown in the inter cropping pattern:
\[\to \]Cotton + moong bean
\[\to \]Finger millet + cow pea
\[\to \] Soyabean + maize
\[\to \]Ground nut + sunflower
\[\to \]Wheat + mustard
Fig. 5.6
Advantages of inter-cropping:
(i) Increases productivity per unit area.
(ii) It saves time and labour of the cultivators and makes better use of resources.
(iii) Both crops can be sown and harvested and threshed separately.
(iv) Chance of spreading the disease and pests are less.
(v) Specific fertilizers required for each crop can be added.
(vi) The produce of each crop can be marketed separately.
Table 5.7: Comparison between mixed cropping and inter-cropping
|
Mixed cropping |
Inter-cropping |
|
(i) It minimize the risk of crop failure. |
(i) It increases crop productivity per unit area. |
|
(ii) There is no pattern of sowing. |
(ii) The different crops are sown in separate rows or strips. |
|
(iii) Seeds of two crops are mixed before sowing. |
(iii) Seeds of two crops are not mixed. |
|
(iv) Only a common type of fertilizers can be added. |
(iv) Specific fertilizers can be provided to each crop. |
|
(v) Crop specific pesticides can not be sprayed. |
(v) Crop specific pesticides can be sprayed without difficulty. |
|
(vi) Both crops have to be harvested and threshed simultaneously. |
(vi) Both crops can be easily harvested and threshed separately. |
|
(vii) There is some mixing of the produce of different crops. |
(vii) There is no mixing of produce of different crops. |
|
(viii) More chances of disease and pests to spread. |
(viii) Less chances of disease and pests to spread. |
Crop rotation
The practice of growing two or more different kinds of crops on a piece of land in a pre-planned succession is called crop-rotation. The rotation of crops on the same piece of land may be done for a year or for longer period of time like two or three years. Different crops are chosen so that soil fertility is not affected. For example, potato require more potash, but wheat requires more nitrates. Generally a leguminous crop is rotated with non-leguminous crop.
Leguminous plants bear modulated roots. The root nodules contain nitrogen fixing becteria of the genus Rhizobium. The bacteria convert molecular nitrogen into nitrogen compounds. These nitrogen compounds enrich the leguminous crop as well as soil. This makes up the deficiency of nitrogen caused by growing cereal crop like rice or wheat in the field.
Conditions for Crop Rotation:
(i) Depending upon the duration, crop rotation is done for different crop combinations.
(ii) The availability of moisture and irrigation facilities decides the choice of the crop to be cultivated after one harvest.
(iii) If the crop rotation is done properly, then two or three crops can also be grown in a year with good harvests.
Advantages of Crop Rotation:
(i) It reduces the need of fertilizers as nitrogen supply is maintained in the crop field when legume crops are alternated with other crops.
(ii) When different crops are grown on the fields one after another, the yields of produce obtained are greater then when the same crops are grown year after year.
(iii) There is optimum utilization of nutrients as different crops obtain nutrients from different layers of soil.
(iv) By alternation, between deep and shallow rooted crops, the soil may be utilized completely.
(v) With the help of crop rotation, the life cycles of weeds, insects and pathogens can be broken naturally. It helps in controlling all these harmful organisms. It also helps to reduce the cost of pesticides and weedicides etc.
Like human beings, the crop plants also have to face the threat of weeds, insect, pests and disease. If they are not controlled at the appropriate time then they can damage the crops so the much that most of the crop may be destroyed. Hence crop protection management is also very necessary for the crop improvement.
Taking care of protecting crops from their pests, pathogens and weeds is called crop protection management.
If weeds, pests and pathogens of crop plants are not controlled, they can damage 50-70% crops. There are various methods by which pests and diseases can be controlled. One of the most common and effective methods is the use of pesticides, weedicides and fungicides. Toxic chemicals used to kill pests e.g. weeds, insects, mites, rodents and fungi are called pesticides.
However, higher doses of pesticides are toxic to many useful bird and animals including human beings. They are environmental pollutants as well. Some of them degrade slowly and undergo bio magnification. Therefore, their use should be restricted and preventive measures should be preferred like-
(i) Resistant varieties,
(ii) Optimum sowing time,
(iii) crop rotation and intercropping,
(iv) Summer plugging.
Three different modes of crop protection management are:
6.1 Weed Control
Weeds are unwanted plants which grow along with the crop. The weeds may sometimes be a crop plant or plant of another variety of same crop. For example, a mustard plant growing spontaneously in wheat field is considered as weed. Similarly, a wheat plant growing spontaneously in mustard field is called as weed.
Some of the characteristics of weeds are:
(i) Weeds compete with the crop plants for soil nutrients, water, sunlight, and space and thereby reduce crop yield.
(ii) A weed is usually characterized by rapid growth, and it typically replaces other desirable plants.
(iii) Weeds spread crop pests and diseases by acting as alternate host to insect and pathogens.
(iv) The weeds may produce toxic substances which may interfere with growth of crop plants.
(v) During harvesting seeds of weeds get mixed with crop to downgrade its quality.
Some Common Weeds / Classification of Weeds
Fig. 6.2: Some Common Weeds
During kharif season, short statured (ground nut), short duration (maize and milletes) and slow growing (pigeon pea) crops are more susceptible to weeds.
Methods of weed control:
Some of the methods of weed control are:
(i) Physical Methods: These include:
(ii) Chemical Methods: These involve killing of weeds by spraying certain chemicals called weedicides or herbicides. Some of the common herbicides are 2, 4-D (2, 4-dichloro phenoxy acetic acid), 2,4,5-T (2,4,5-trichlorophenoxy acetic acid); diurone and TCA (Tnchloro phenoxy acetic acid).
(iii) Cultural Methods: These includes:
(iv) Biological Methods: In this method, a natural enemy of weed plant is used. b or toe success of this method, it is necessary that the destructive agent must be highly specific and should not harm the crop even under starvation conditions. For example pinkly pear cactus was eradicated by using cochineal insect. Mexican Beetle and Cassia can check the growth of Parthenium. Aquatic weeds are controlled by the fish called grass crop.
Various organisms such as rats, insects, bacteria, viruses, fungi etc. which damage the crops and reduce their yield are called pests. Insects attack the crop plants in the following three ways:
6.3 Insect Pests Control
1 Chewing insects: They cut the root, stem and leaf with the help of their chewing mouth parts. They chew and swallow these pieces of plant parts, e.g. locusts, hoppers, caterpillars, etc.
(i) The preventive measures of insect pests-These include:
(ii) By using insecticides: In this method, the insects are destroyed by spraying the affected crop with certain chemicals called insecticides.
Malathion, lindane, and thiodon are sprayed over the crops to control stem and leaf cutting insects. Roots are protected by fumigants and insecticides like chloropyriphos. Sucking insects are controlled by use of systemic insecticides like dimethoate and metasistox.
(iii) Biological control: In this method of insect control, some birds, insects or other organisms are deliberately put in the affected crop fields to kill the insert selectively. The biological method of pest control is highly specific and non-polluting.
Some Common Insects of Stored Grain
2. Rice weevil (Sitophilus oryza)-Both grub and beetle (adult) damage rice.
Fig. 6.4: Some insects of stored grains
6.4 Plant Diseases
Disease causing organisms are called pathogens. The disease of plants are caused by organisms such as fungi, bacteria, viruses and insects. These pathogens are present in the soil, water and air. On getting favourable conditions such as optimum temperature and moisture, they become active and infect plants. The diseases reduce the growth and productivity of crops.
Depending upon their occurrence and transmission, the diseases may be soil borne, seed borne, air borne or water borne.
(a) Soil borne disease: Transmitted through soil, e.g. smut of bajara, stem rot of moong bean, wilt of gram.
(b) Seed borne disease: Spread through the seeds, e.g. smut of wheat, red rot of sugarcane, leaf spot of rice.
(c) Air borne disease: Spread through air, e.g. rust of wheat, blast of paddy.
(d) Water borne disease: Transmitted through water, e.g. bacterial blight of rice.
Fig. 6.5.: Common Crop Diseases and Pests
Disease control:
(i) Seed borne diseases can be prevented by sowing healthy seeds and pre-treating seeds with chemicals like Agrosan and Cares an to kill pathogens.
(ii) Soil borne diseases can be prevented by using soil disinfectants and also by crop rotation.
Absence of the same host in successive years results in elimination of the pathogen.
(iii) Air borne diseases can be prevented by spraying specific chemicals, like insecticides, fungicides etc.
(iv) Use of disease resistant crops is a very important method to bring about control of crop diseases.
Preventive and Control Measures:
Spoilage of grains during storage can be prevented and controlled by using the following measures:
(1) Cleaning of the produce before storage: The grains and other agricultural produce should be properly cleaned and dried before their storage. They should be packed in new gunny bags before keeping in god owns, warehouses or stores.
(2) Drying: For safe storage the seeds, grains and other produce should have moisture content below 9%. It is desirable that the grains and the nonperishable food such as flour, sugar, spices and nuts should be dried first in sunlight and then in shade.
(3) Fumigation: Chemical pesticides are used as fumigants, i.e. the solution of pesticides is converted into fumes. These fumes kill the insect pests and other harmful biological agents. For example, two tablets (3g each) of aluminium phosphide (black poison) can be used to protect one tone grain.
(4) Safe Storage: Godown, ware houses and stores should be properly cleaned, dried and repaired. Pathways should be provided between the stacks of grain tilled bags, for the periodic inspection, for spraying or for fumigation.
Animal husbandry is the scientific management of animal livestock. Which in eludes various aspects such as feeding, breeding, shelter and disease control.
7.1. Cattle Farming
A breed is a group of animals usually developed by deliberate selection which are similar in most of character such as general appearance, size etc. In India there are about 30 indigenous breeds of cows and 10 breeds of buffaloes. Depending upon their utility the indigenous breeds are also classified into the following groups:
(i) Milch Breed: The cows of this breed are high yielding but their bullocks are not very useful as work animals. For example gir of Gujrat, Sahiwal of Punjab and Haryana, Red Sindhi and Deoni of Andhra pradesh are main milch breed. Sahiwal breed is superior to other milk yielding cows.
(ii) Drought Breeds: The males of this breed are beast for burden. These are helpful in pulling carts, ploughing land and transporting materials. Their cows are less milk-yielding. Nagori, Hallikar and Malvi are the cows of this breed.
(iii) General utility or Dual Purpose Breeds: The cows of this categories are high milk yielding and their bullocks are also good work animals. Deoni, Sahiwal, Thar parker, Kankrej and Dongi are the main cows of this breed.
The best known breeds of Indian buffaloes are Mehsana, Nagpuri (Gujrat), Surti, Jaffrabadi, Bhadawari, Nili Ravi and Murrah of Punjab and Haryana.
Fig. 7.2: Indigenous breeds of cow and buffalo
Fig. 7.3: Exotic breeds of cow
7.4. Important Exotic Breeds of cows: For the production of good milk yielding cows, Indian cows have been crossed with Europian bulls. Following are some exotic milch cows:
(i) Holstein: This is Friesian breed of Holland, which gives 3200 litres milk per year.
(ii) Jersey: This is the breed of Jersey Island of England.
(iii) Brown swiss: This is dual purpose breed of Switzerland.
(iv) Ayrshire: This is a breed from Scotland
Improved breeds of dairy cows have been developed in our country at the National Dairy Research Institute (NDRI), Kamal (Haryana). The high milk yielding breeds of cow developed in India through cross breeding are-Karan-fries, Karan-swiss, Frieswal etc.
7.5. Milk Production: Production of good quality milk depends on several factors.
Some of them are:
Dr. V. Kurion, founder chairman of the National Dairy Development Board (NDDB), is called the architect of India's modern dairy industry and the father of white revolution.
7.6. Diseases of cattle: Cattle suffer from a number of diseases. The diseases, besides causing death, reduce milk production. The disease of cattle are caused by worms, flukes, bacteria, fungi, viruses and many other parasites. The parasites of cattle may be internal or external.
The external parasites include blood sucking lice, licks, and mites and cause skin diseases. The internal parasites live inside the body. They include Ascaris, Liver fluke etc. and cause stomach, liver and intestine diseases. Many other infectious disease are caused by fungi, bacteria and viruses. Some of them are- Anthrax, Haemorrhgic septicemia, foot and mouth disease, Rinderpest (Cattle plague), Tuberculosis etc.
Prevention of Cattle Disease:
(i) The animals should be kept in spacious well ventilated shelters to protect them from, rain, heat and cold.
(ii) Cattle sheds should be cleaned regularly.
(iii) The animals should be given good nutritive feed and clean water.
(iv) The animals should be vaccinated to immunize them against common diseases or infections.
"Poultry is the branch of animal husbandry concerned with rearing of birds for eggs and meat.". In other words rearing of egg laying and meat yielding birds, their breeding and collection of their products are called poultry.
Poultry farming is raising of domestic fowls for egg production and chicken meat. Hence, improved poultry breeds are developed and farmed to produce the desired fowls. Depending upon the utility or time of requirement, the fowls can be categorised as:
(i) Growers: The first phase of life of poultry is growing period (up to sexual maturity).
During this period, the chicken are called growers.
(ii) Layers: The period from sexual maturity till the end of egg laying is called laying period and the chickens which are used for producing eggs are called layers.
(iii) Broilers: Those fowls which are used for producing meat are called broilers.
(iv) Poultry Breeds: Cross breeding of the following breeds is done for variety improvement of the fowls:
Indigenous or Desi breeds: Aseel or Indian game, Kadaknath, Chhattisgarh and Busra are the desi breeds of fowls. The most popular breed is Aseel. The Peela, Yakub, Nuries, and Kajal are the most popular varieties of this breed. They are hardy (strong) and possess natural immunity against common diseases. The disadvantages of desi hens are:
(i) They are smaller in size and slow growing.
(ii) They lay small-sized and less number of eggs (60 eggs/year). Aseel provides high quality of meat but it is not a good egg layer. The average weight of hens varies from 3 to 4kg and cocks from 4 to 5 kg.
Exotic breeds: The high egg yielding exotic breeds of fowls which have been successfully acclimatized in India are White leghorn, Rhode Island Red, Plymouth and Black Minorca. White Leghorn is the most popular egg laying breed all over the world. It has small sized body and requires less feed for its maintenance. Rhode Island Red is also good layer and broiler.
Fig. 8.1: Some Exotic Breeds of fowl
Above breeds ore cross breed in such a way that following desirable traits could be developed in the new breeds:
(i) Number and quality of chicks.
(ii) Dwarf broiler parent for chick production at the commercial level.
(iii) Low maintenance requirements.
(iv) Reduction in the size of the egg laying birds so that they may utilise more fibrous and cheaper diet6.
(v) Summer adaptation capacity or tolerance to high temperature.
Egg and Broiler Production:
The broilers are used for meat, these are different from the layers. Following conditions are required for their fast growth and low mortality-
(i) The daily food requirement of broilers is protein rich diet with adequate fat so that good growth rate and better feed efficiency may occur. Vitamin A and K content should be high in the poultry feed.
(ii) Care is also taken to avoid mortality and to maintain feathering and carcass quality (carcass is the dead body of an animal especially slaughtered one and dressed for food).
Pisciculture or fishery involves the rearing and breeding offish, shell fish, and other aquatic animals scientifically. Other aquatic animals include prawn, crabs, lobsters, edible oysters etc.
Fish is rich source of proteins. A large section of Indian population especially in coastal areas uses fish as food. Depending upon the way of obtaining fishes, there are two categories of them, namely.
(i) Capture fishing: When the fishes are obtained from the natural resources it is called capture fishing.
(ii) Culture fishing: When the fishes are obtained by fish farming (or growing of fishes in the artificial ponds), it is called culture fishing.
The water source of the fish can be either sea water (marine water) or fresh water (rivers and pond water). Fishing can thus be done both by capture and culture offish in marine and fresh water ecosystem.
The term aquaculture is used to describe the culture of aquatic organisms both animals and aquatic plants in fresh or marine water.
9.1. Marine Fisheries: The culture and capture of marine fishes is called Mariculture Some of the characteristic features of Indian marine fisheries are-
(i) India's marine fisheries include 7500 km of coast line and the deep sea.
(ii) Marine fishes are caught by making use of fishing nets placed in fishing boats. Yields of fishes are increased by locating many fishes in the open sea using satellites and echosounders.
(iii) Popular marine fish varieties are pomphret, mackerel, tuna, Bombay-duck and sardines.
(iv) Some marine fishes of high economic value are also cultured in marine water. These are
(a) finned fishes like mullets, bhetki and pearl spot
(b) Shellfish such as prawns, mussels, seaweed and oyesters. The oyesters are also grown for pearls.
9.2. Inland fisheries: Inland fisheries can be setup by various modes like-
(i) Fresh water resources: Such as canals, ponds, reservoirs and rivers.
(ii) Brackish water resources: They include estuaries and lagoons where sea water and fresh water (rivers) mix together. They also act as fish reservoirs. The yield of capture fishing in these areas is not high. Most fish production from these resources occur through aquaculture.
(iii) In rice fields: In our country fish culture is also done in combination with a paddy crop so that fishes are grown in the water present in the paddy fields.
(iv) Composite fish culture system: This is a very intensive fish farming system. It is also known as polyculture of fish. In this culture system, the combination of five or six species is used in a single pond. Out of the six species, three are of Indian origin and three are exotic. The exotic species are silver carp, grass carp, and common carp. The Indian species are catia, Rohu and Mrigal. The species are selected in such a way that they should not compete for food, i.e. they should have different types of food habits. As a result, the food available in all the parts of the pond is used.
For example:
(i) Catlas and silver carp are surface feeders.
(ii) Rohu, feed in the middle zone of the pond i.e. column feeder.
(iii) Mrigals and common carps are bottm feeders and
(iv) Grass carps feed on the weeds.
In this way all of these species together use the food in the pond without competing with each other. This increases the fish yield from the pond.
Fig 9.3.: Prawns. A, Marine Prawn (Peneaus monodon).
B, Freshwater Prawn (Macro brachium rosenbergii)
Fig. 9.4.: Types of fish in composite culture
Problems with composite fish culture: There are certain problems in composite fish farming.
One of the major problems is availability of good quality seeds (i.e, eggs or spawn). It is because these fishes breed only in monsoon months. So the seeds are available only for a short duration.
Alternatively, if one tries of obtain seeds of these fishes from natural sources, i.e. from rivers, then the availability of pure seeds is not sure. It is because the seeds of desired species get mixed with those of undesired species.
To overcome these problems of composite fish culture and to get desired quality seeds, scientists experimented and worked out to breed these fishes in ponds. They induced breeding techniques with the help of hormonal stimulation. The hormones were extracted from the pituitary glands of carps. This new breeding technique ensured the supply of pure seeds offish in desired quantity and led to Blue revolution through fish farming.
Economic Importance:
(i) Fish is an important source of food rich in proteins.
(ii) Fish liver oil is rich in vitamin A and D.
(iii) Marine fish are rich in iodine and other minerals.
The practice of rearing of bees is called apiculture. It is concerned with the commercial production of honey and wax. Bee keeping is a low investment, less problematic and highly profitable enterprise. Therefore, farmers practice is as an additional source of extra income.
Importance of Bee-keeping: Beekeeping provides us honey (A sweet edible fluid containing sugar, water, mineral, vitamins, amino acids, enzymes and pollen).
It is used in treatment of digestive disorders, liver ailments, cough, cold, sore throat and ulcers of lounge, stomach and intestine. Wax (secreted by wax glands of worker bees for construction of beehive) is used in medicines.
Bee keeping helps in cross pollination of flowers of crop plants. Since pollens are transferred from one flower to another by bees while collecting the nectar. It has been found that in some crops like mustard and fruits, yield is increased substantially by simultaneous bee keeping.
Fig. 10.1: Honeybee. A part of hive in section, showing egg, larvae and pupa and adult castes (queen, drone and worker)
Species of Honey Bee:
In India, both local and exotic species are used for commercial production of honey. The local species are Apis cerana or Apis indica (Indian bee), Apis dorsata (rock bee) and Apis florae (little bee). The exotic species are Apis mellifera (Italian species) and Apis adomsoni.
Advantages of Italian bee over local species of bee:
(i) The Italian species Apis mellifera, has been introduced in India to increase yield of honey as it has high honey collection capacity. Therefore, .this variety is commonly used for honey production at commercial scale.
(ii) They sting somewhat less.
(iii) They stay in a particular beehive for long periods and breed very well.
Division of Labour: The honey bee is a social insect and represents a well organized system of division of labour. Each honey bee colony consists of three castes-(i) One queen which is functional female produced from fertilized egg and can lay up to 15,000 eggs in a day and can live for three years, (ii) There are 10,000-20,000 workers (sterile female), which have undeveloped reproductive organs and (iii) Few hundred drones (males), which are heavily built as compared to the workers and queen. The only function of drones is to mate with the queen Their life span is 57 days.
Management for high yield of honey: There are many factors which determine the quality and quantity of honey and need to be kept in mind while keeping bee. These are
(i) Beehive: It is a box raised over a stand. The box has a wire gauze covered brood chamber for egg laying and a multi frame honey chamber for honey collection as honey reserve. Each beehive is 46\[\times \]23cm in size.
(ii) Pasturage: The quantity of flowers available to the bees for nectar and pollen collection is called pasturage. Pasturage or flora always determine the quality of honey as the pollen grains and nectar serve as protein food for bees.
Pasturage is different in different geographical regions and locations, plains and mountains. The pasturage flora of honey bee include coconut, mango, almond, bar seem, coriander, sunflower, mustard, apple etc. The quality and taste of honey depends upon the pasturage or flora.
(iii) Apiary location: The place where bees are raised and breed to get honey is called apiary. Apiary has a number of beehives. Apiary has to be setup in an area, having good flora or pasturage.
(iv) Swarming: It is a part of reproductive cycle in honey bees. As a young bee is ready to take over the function of queen, the old queen along with a sizable population of workers, leaves the hive to build a new colony. The process is known as swarming. Frequent transfers result in low yield of honey. The maintenance cost of hives is also increased.
(v) Honey flow: Honey flow season is the total time period in which bees collect pollen and nectar. Therefore, apiary should be established at place where abundant flowers are present for a longer duration.
(vi) Protection from diseases and pests: Some of the common pests of bees are wasps, mites, king crows and wax moths. Wasps may be controlled manually. Wax moth by exposing bees in beehive to sun. Green bee eater and king crow are scared away by some devices.
Honey bees also suffer from nosema disease caused by a protozoan Nosema apis. Dysentery, paralysis and acrine disease are caused by a parasitic mite Acarapis woodi.
Fig.10.2
Chapter at a Glance and Glossary
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