Notes on Improvement in Food Resources CBSE 9 science
NTRODUCTION
Food is an organic substance which is necessary for the existence of all living organisms. It supplies nutrients like proteins, carbohydrates, fats, vitamins and minerals to our body Thus we are dependent on animals and plants for food. Therefore it is necessary to increase our production efficiency for both crops and livestock.
The green revolution has contributed to increase food-grain production and the white revolution has led to better and more efficient use as well as availability of milk.
IMPORTANT TERMS AND CONCEPTS
1. Crop Production: Crops and planta cultivated by human beings for food, fodder and other materials. The important types of crops are
Cereal Crops:- Wheat, rice, maize, millets and sorghum provide carbohydrates for energy requirement
Pulses:- like gram, pea, black gram, green gram, pigeon pea, lentil provide proteins.
Oilseed Crops:- Groundnut, soyabean, sesame, castor mustard, linseed and sunflower provide fats.
Vegetables, spices and fruits:- provide a range of vitamins and minerals along with small quantities of proteins, carbohydrates and fats.
Food Crops and Fodder Crops:- Berseem, cata or sudan grass are raised for food for the livestock.
2. Photoperiod:- It is the response of an organism to changes in day length i.e. photoperiods are related to the duration of sunlight. Growth of plants and flowering are dependent on sunlight.
3.Crop Seasons: Different crops require different climatic conditions, temperatures and photoperiods for their growth and completion of their life cycle. Cropping activities go on all the year-round in India, provided water is available for the crops.
There are two distinct seasons
1.Kharif Season: These crops are grown in rainy season, te kharif season from the month of June to October.
Examples are paddy, soyabean, pigeon pea, maize, cotton, green garm and black gram.
2.Rabi Season: These crops are grown in winter season, i.e. rabi season from November to April.
Examples are wheat, gram, peas, mustard, linseed, etc.
4. Improvement in Crop yields: The increased production can be achieved by adopting practices involved in farming and are divided into three stages-
Firstly, the choice of seeds for plants,
secondly, the nurturing of the crop plants and
thirdly, the protection of the growing and harvested crops from loss.
Thus, the major groups of activities for improving crop yields can be classified in three steps as follows
1. Crop variety improvement,
2. Crop production improvement a
3. Crop protection management.
1. Crop Variety Improvement: This approach depends on finding a crop variety that can give a good yield. Varieties of crops can be selected by analysing various useful characteristics such as disease resistance, response to fertilisers, product quality and high yields.
One way of incorporating desirable characters into crop varieties is by hybridization. Another way is by introducing gene .
The factors for which variety improvement is done are,
* Higher Yield : To increase the productivity of crop per acre
* Improved quality: Quality consideration such as haking quality, protein quality, oil quality and preserving quality of crop products.
* Biotic and Abiotic Resistance: Crops production can go down due to biotic and abiotic stresses under different situations. Varieties resistant to these stresses can improve crop production.
* Change in Maturity Duration: The shorter the duration of the crop from sowing to harvesting, the more economical is the variety.
* Wider Adaptability: Developing varieties for wider adaptability will help in stabilising the crop production under different environmental conditions.
2.Crop Production Management: It depends upon the financial condition of the farmer, as to which cropping system and production practices he uses. Thus, production practice can be at different levels. They include no cost production, low cost production and high cost production practices.
Uses of manures and fertilizeres for supply of nutrients, irrigation, nosed cropping, inter cropping, crop rotation are some of the crop producten practices required for olitaininghigh yields.
Nutrient Management : The inorganic chemical substance which the planta absorb from
their surroundings are called nutrients. Nutrients are supplied to planta by air. water and soil. There are sisteen nutrients essential for plants. To increase yield, the soil can supply nutrients in the form of manures and fertilizers.
Characteristics of an Essential Plant Nutrients:-
a.In the absence of the element, the plant is not able to complete its life cycle
b.The deficiency of a particular element can be prevented or corrected only by supplying that nutrient
c.The element must have a direct influence on the plant nutrition and metabolism
Classification of Nutrients: On the basis of quantities required, the 13 nutrients needed for plant growth have been grouped into following two classes
i-Macronutrients: The essential elements utilised by plants relatively in large quantities are called major nutrients or macronutrients. The six essential macronutrients are-Nitrogen, Phosphorus, Potassium, Calcium, Magnesium and Sulphur.
Of these six macronutrients, nitrogen, phosphorus and potassium (Le, NPK) are required by plants in greater amounts and are called primary elements or primary nutrients.
ii-Micronutrients: They are the essential elemente which are used by plants in small quantities or traces. The seven micronutrients are-Iron, Manganese, Boron, Zinc, Copper, Molybdenum and Chlorine.
Manures: Manures are organic substances obtained through the decomposition of plant wastes like straw and animal wastes like cow dung. The decomposition is brought about by the action of microbes.
Manures contain large quantities of organic matter.
• Manures contain nutrients in small quantities and therefore are needed to be supplied to crops in large quantities.
*Manures are bulky and so it is inconvenient to store and transport them.
Types of Manures: Based on the kind of biological material used, manures are classified as follows:
i-Farmyard Manure (FYM): It is the decomposed mixture of cattle excreta and urine.(along with left over organic matter such as roughage or fodder.)
ii-Compost: It is the process in which farm waste material like livestock excreta, vegetable waste, animal refuse, domestic waste, sewage waste, straw etc. are decomposed in pits.
iii- Vermi-compost: It is the process when compost is prepared by using earthworms to decomposition of plants and animal refuse. Here the earthworms help to breakdown the wastes. This activity along with the excreta of the worms makes the compost rich in nutrients.
iv-Green Manure: This practice includes growing or ploughing and mixing of green crops with soil to improve physical structure and soil fertility.
Advantages of Manures:
* Manures enrich the soil with nutrients.
* Manures add organic matter to the soil, which improves soil texture and increases water holding capacity and drainage in soil.
* They provide food for soil organisms.
Disadvantages of Manures:
* Manures are inconvenient to handle, store and transport as they are bulky.
* The nutrients of manures are released slowly
* They are not nutrient specific.
Fertilisers:
Fertilisers are inorganic or organic compounds containing one or more essential plant nutrients which are used for increasing the fertility of soil.
Advantages of Fertilizers
*They contain much higher amount of nutrients in comparison to manures and are therefore required in very small quantities.
• They are manufactured commercially from chemicals.
• They are easy to use, store and transport.
* Being soluble in water, they are easily absorbed by plants.
• Fertilisers are generally nutrient-specific i.e., they can supply one or more specific nutrients.
Types of Fertilisers: They are divided into four groups-
(1) Nitrogenous Fertilisers: These fertilizers supply the macronutrient nitrogen. Examples: Urea, Ammonium nitrate, etc.
i) Phosphatic Fertilisers: They are the source of macronutrient phosphorus. Examples: Single Superphosphate, Triple Superphosphate.
(ii) Potassic Fertilisers: These fertilisers supply potassium which is one of the essential macronutrients to the plants. Examples: Potassium Chloride, Potassium Sulphate, etc.
(iv) Complex Fertilisers: When a fertiliser contains at least two or more nutrients it is called complex fertilisers. Examples: Nitrophosphate, Ammonium phosphate, etc.
Irrigation: It is the process of supplying water to crop plants in the fields by means of canals, reservoirs, wells and tube-wells, etc. It depends on following two factors:
(i) Crop-based irrigation,i.e, on the nature of crop plants
(ii) Soil-based irrigation,i.e, on the nature of soil of the crop fields.
Irrigation System:--It is the design of equipment and technique of replenishing the soil water deficit by applying irrigation water. The commonly used irrigation systems are:
(i) Wells: They are constructed wherever exploitable ground water is present. Wells are of two types:
(a) Dug wells, where the water is collected from water bearing strata.
(b) Tube wells, where it can trap water from the deeper strata.
(ii) Canals: In this system, the man-made canals receive water from one or two reservain or from rivers.
(iii) Tanks: They are small storage reservoirs which catch and store water for smaller catchment areas.
(iv) River Valley System: In southern parts of India, there are many steep and narrow riverine valleys where rainfall is heavy but concentrated for four or five months. This is followed by dry season, so the bottom lands of the valleys are used for a single rice crop.
(v) River Lift Systems: In this system, water is directly drawn from the rivers in the areas near rivers.
Advantages of Irrigation: Irrigation is one of the oldest agricultural techniques practiced by humans and has many advantages:
(i)The supply of water by irrigation is regular and reliable.
(ii) Irrigation water supplied by rivers in flood carries silt which is added to soil, enhance fertility and thus crop yields.
(iii) With irrigation, cultivation can be done all the year around.
Mixed Cropping: It is the practice of growing two or more crops simultaneously on the same piece of land. Some mixed cropping practices are:
(i) Soyabean+ Pigeonpea
(ii) Groundnut + Sunflower
(iii) Wheat +Gram
(iv) Wheat+Mustard
(v) Cotton+ Mungbean etc.
Advantages of Mixed Cropping:
(i)The risk of total crop failure due to uncertain monsoon is reduced.
(ii) Farmers tend to harvest a variety of produce such as cereal, pulses or vegetables
(iii) Due to complementary effect of component crops, yield of both crops is increased, i.e.wheat and gram.
(iv) Chance of pest infestation are greatly reduced.
Intercropping: It is the process of growing two or more crops simultaneously on the same field in a definite pattern. A few rows of one crop alternate with a few rows of a second crop.
Example: Soyabean+ maize, finger millet (bajra)+ cowpea (lobia) etc
The crops are selected such that their nutrient requirements are different.
Advantages of Intercropping:
(i)It ensures maximum utilisation of the nutrients supplied.
(ii)It also prevents pests and diseases from spreading to all the plants belonging to one crop in a field. In this way, both crops can give better returns.
(iii)Soil erosion is effectively arrested.
(iv)It helps to maintain soil fertility.
Crop Rotations:-- it is defined as the practice of growing of different crops on a piece of land in a preplanned succession.
Depending upon the duration, crop rotation is done for different crop combinations. If crop rotation is done properly than two or three crops can be grown in one year with good harvests.
Advantages of Crop Rotation
(i)Crop rotation helps in replenishment of soil fertility.
(ii)It prevents depletion of selective nutrients.
(iii)It prevents building up of diseases and pests of particular crop.
(iv)It enhances the production by increasing the soil fertility.