NCERT Class 9 Science Chapter 12: Improvement in Food Resources - A Complete Guide

Introduction to Improvement in Food Resources

Welcome, students! In this comprehensive guide, we will explore Chapter 12 of the NCERT Class 9 Science textbook, "Improvement in Food Resources." All living organisms require food for energy, growth, and bodily repair. We obtain most of this food from agriculture and animal husbandry. As you know, India is a very populous country, with a population exceeding 1.3 billion people and it is still growing. To feed this ever-increasing population, we will soon need more than a quarter of a billion tonnes of grain every year. This can be accomplished by farming on more land. However, with increasing urbanization and industrialization, we have limited land available for cultivation. Therefore, it is crucial not to increase the area of land under cultivation but to increase the efficiency of production for both crops and livestock.

This chapter delves into the scientific principles and techniques that help us maximize the yield from our farms and livestock. We will understand the significance of the Green Revolution, which contributed to increased food-grain production, and the White Revolution, which led to the better and more efficient use as well as availability of milk. These revolutions highlight that simply increasing grain production for storage in warehouses cannot solve the problem of malnutrition and hunger. We need sustainable practices that ensure food security for everyone. This involves a multi-pronged approach covering everything from selecting the right seeds to protecting stored grains and managing our livestock effectively. Let's begin this journey to understand how we can scientifically manage our food resources for a healthier and more secure future.

Improvement in Crop Yields

The success of crop yield depends on a series of well-managed agricultural practices. These practices can be broadly categorized into three main stages. By focusing on these three areas, we can systematically improve our agricultural output.

• Crop variety improvement: Selecting and developing plant varieties that have desirable characteristics like high yield, disease resistance, and better quality.
• Crop production improvement: Managing the various aspects of nurturing the crop, such as providing nutrients, water (irrigation), and adopting suitable cropping patterns.
• Crop protection management: Protecting the growing and harvested crop from weeds, pests, diseases, and other threats to minimize loss.

1. Crop Variety Improvement

The primary goal of crop variety improvement is to develop new strains of crops that are superior to existing ones. The selection of varieties is a crucial first step. Scientists and farmers look for specific desirable traits to enhance the overall productivity and usability of the crop.

Factors for which variety improvement is done:

• Higher Yield: The most fundamental objective is to increase the productivity of the crop per acre. This ensures that more food is produced from the same amount of land.
• Improved Quality: The quality of the crop product is as important as the quantity. Quality considerations vary from crop to crop. For instance, baking quality is important in wheat, protein quality in pulses, oil quality in oilseeds, and the preserving quality in fruits and vegetables.
• Biotic and Abiotic Resistance: Crops face constant threats from biotic factors like diseases, insects, and nematodes, and abiotic factors like drought, salinity, waterlogging, heat, cold, and frost. Varieties that are resistant to these stresses can survive adverse conditions and give better yields.
• Change in Maturity Duration: Developing varieties with shorter maturity durations allows farmers to grow multiple rounds of crops in a year from the same field. This short duration also reduces the cost of crop production and increases overall profitability.
• Wider Adaptability: Developing varieties that can be grown under different environmental conditions (different climates, soils) helps in stabilizing crop production. A single variety can then be grown across various regions.
• Desirable Agronomic Characteristics: For fodder crops, farmers prefer varieties that are tall and have profuse branching to provide more foliage. For cereals, dwarfness is a desired trait, as shorter plants consume fewer nutrients and are less prone to being knocked down by wind, making harvesting easier.

To achieve these traits, scientists use a technique called hybridisation. Hybridisation refers to the process of cross-breeding between two genetically dissimilar plants to obtain a new plant or variety with the desired characteristics from both parents. This can be:

• Intervarietal: Between different varieties of the same species.
• Interspecific: Between different species of the same genus.
• Intergeneric: Between different genera.

Another modern way to improve crop varieties is by introducing a gene that would provide the desired characteristic. This results in genetically modified crops (GMCs). These crops are engineered to have specific traits like pest resistance (e.g., Bt cotton) or improved nutritional value.

2. Crop Production Management

After selecting the right crop variety, the next crucial step is to nurture it effectively. Crop production management involves controlling the various factors that influence the growth and health of the plant. In India, farmers range from those with small plots to those with very large holdings. The financial conditions of these farmers also play a significant role in the agricultural practices and technologies they can adopt. Their capacity to invest determines the input, cropping system, and production practices. Therefore, production practices can be at different levels: 'no cost' production, 'low cost' production, and 'high cost' production. This section covers the three key components of production management: nutrient management, irrigation, and cropping patterns.

Nutrient Management

Just like us, plants require nutrients for their growth and development. These nutrients are supplied to plants by air, water, and soil. There are sixteen nutrients which are essential for plants. Air supplies carbon and oxygen, and hydrogen comes from water. The soil is the primary source for the remaining thirteen nutrients. Of these, six are required in large quantities and are therefore called macro-nutrients. The other seven nutrients are used by plants in small quantities and are therefore called micro-nutrients.

• Macro-nutrients: Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulphur (S).
• Micro-nutrients: Iron (Fe), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), Molybdenum (Mo), Chlorine (Cl).

Deficiency of these nutrients affects physiological processes in plants, including reproduction, growth, and susceptibility to diseases. To increase the yield, the soil can be enriched by supplying these nutrients in the form of manure and fertilizers.

Manure: Manure is prepared by the decomposition of animal excreta and plant waste. It contains small quantities of nutrients but large quantities of organic matter, which is vital for soil health. Manure helps in enriching the soil with nutrients and organic matter and increasing soil fertility. The bulk of organic matter in manure helps in improving the soil structure. This involves increasing the water-holding capacity in sandy soils and improving drainage in clayey soils.

Based on the kind of biological material used, manure can be classified as:

• Compost: This is produced when farm waste material like livestock excreta, vegetable waste, animal refuse, domestic waste, straw, and eradicated weeds are decomposed in pits. This process is known as composting.
• Vermi-compost: When the above process of compost preparation is hastened by using earthworms to decompose plant and animal refuse, it is called vermi-composting.
• Green Manure: Before sowing the crop seeds, some plants like sun hemp or guar are grown and then mulched by ploughing them into the soil. These green plants turn into green manure, which helps in enriching the soil in nitrogen and phosphorus.

Fertilizers: Fertilizers are commercially produced plant nutrients. They supply nitrogen, phosphorus, and potassium (NPK). They are used to ensure good vegetative growth (leaves, branches, and flowers), giving rise to healthy plants. Fertilizers are a major factor in the higher yields of high-cost farming. However, their excessive use can be harmful. Continuous use can destroy soil fertility because the organic matter in the soil is not replenished, and microorganisms are harmed. They can also cause water pollution by washing away into nearby water bodies.

Here is a comparison between manure and fertilizers:

Organic farming is a farming system with minimal or no use of chemicals as fertilizers, herbicides, pesticides etc., and with a maximum input of organic manures, recycled farm-wastes, and bio-agents, with healthy cropping systems.

Irrigation

Water is essential for the proper growth and development of plants. Most agriculture in India is rain-fed, meaning it depends on the monsoon. However, monsoons can be irregular and insufficient. Therefore, ensuring that crops get water at the right stages during their growing season can increase the expected yields of any crop. This artificial supply of water to crops is called irrigation.

Various irrigation systems are used to supply water to agricultural lands:

• Wells: There are two types of wells, namely dug wells and tube wells. In a dug well, water is collected from water-bearing strata. Tube wells can tap water from deeper strata. Water is lifted by pumps for irrigation.
• Canals: This is a very elaborate and \textensive irrigation system. Canals receive water from one or more reservoirs or from rivers. The main canal is divided into branch canals having further distributaries to irrigate fields.
• River Lift Systems: In areas where canal flow is insufficient or irregular due to inadequate reservoir release, the lift system is more rational. Water is directly drawn from the rivers for supplementing irrigation in areas close to rivers.
• Tanks: These are small storage reservoirs, which intercept and store the run-off of smaller catchment areas.

Recent initiatives have focused on water conservation through techniques like rainwater harvesting and watershed management. This involves building small check-dams which increase the groundwater levels and prevent soil erosion.

Cropping Patterns

Different ways of growing crops can be used to give maximum benefit. These patterns help in avoiding crop failure, improving soil fertility, and maximizing yield.

• Mixed Cropping: This involves growing two or more crops simultaneously on the same piece of land. For example, growing wheat + gram, or groundnut + sunflower. The main benefit is that it reduces the risk of total crop failure. If one crop fails due to disease or lack of rain, the other may still provide a harvest.
• Inter-cropping: This is a more systematic version of mixed cropping where two or more crops are grown simultaneously on the same field in a definite pattern. A few rows of one crop alternate with a few rows of a second crop. For example, soybean + maize, or finger millet (bajra) + cowpea (lobia). The crops are selected such that their nutrient requirements are different. This ensures maximum utilisation of the nutrients supplied, and also prevents pests and diseases from spreading to all the plants of one crop in a field.
• Crop Rotation: This is the practice of growing different crops on a piece of land in a pre-planned succession. The availability of moisture and irrigation facilities decides the choice of the crop to be cultivated after one harvest. If crop rotation is done properly, then two or three crops can be grown in a year with good harvests. For example, a farmer might plant a nitrogen-fixing legume crop like peas or beans one season, and then a high-nitrogen-demand crop like maize the next season. This helps in replenishing the soil with nitrogen naturally.

3. Crop Protection Management

Once a crop is growing, it must be protected from various threats that can drastically reduce the yield. Field crops are infested by a large number of weeds, insect pests and diseases. If these are not controlled at the appropriate time, they can damage the crops so much that most of the crop is lost.

Weeds: Weeds are unwanted plants in the cultivated field. Examples include Xanthium (gokhroo), Parthenium (gajar ghas), and Cyperinus rotundus (motha). They compete with the main crop for food, space, and light. Weeds take up nutrients and reduce the growth of the crop. Therefore, their removal is essential during the early stages of crop growth to ensure a good harvest.

Methods of weed control include:

• Mechanical Removal: Physically removing weeds by hand (weeding) or using implements like a khurpi or a harrow.
• Chemical Control: Spraying chemicals called herbicides or weedicides, like 2,4-D, which selectively kill weeds without harming the crop.
• Biological Control: Using insects or other organisms that specifically consume and destroy the weed plants.
• Preventive Methods: Proper seed bed preparation, timely sowing of crops, and inter-cropping can help suppress weed growth.

Insect Pests: Insects can attack the plant in three ways: (i) they cut the root, stem and leaf, (ii) they suck the cell sap from various parts of the plant, and (iii) they bore into the stem and fruits. This affects the health of the crop and reduces yields.

Control methods include:

• Pesticides: These chemicals are sprayed on the crops to kill pests. This group includes insecticides, fungicides, and herbicides. However, these chemicals can be toxic to many plant and animal species and cause environmental pollution.
• Resistant Varieties: Using crop varieties that are naturally resistant to certain pests.
• Cultural Methods: Practices like deep summer ploughing can destroy the eggs and pupae of many insects that reside in the soil.

Diseases: Plant diseases are caused by pathogens such as bacteria, fungi, and viruses. These pathogens can be present in and transmitted through the soil, water, and air. Control involves using disease-resistant varieties and spraying fungicides and bactericides.

Storage of Grains: A significant portion of the crop yield can be lost during storage. Factors responsible for such losses are:

• Biotic factors: Insects, rodents, fungi, mites, and bacteria.
• Abiotic factors: Inappropriate moisture and temperatures in the place of storage.

These factors cause degradation in quality, loss in weight, poor germinability, and discoloration of the produce. To prevent this, strict cleaning of the produce before storage, proper drying of the produce first in sunlight and then in shade, and fumigation using chemicals that can kill pests are necessary. Controlled atmosphere storage systems with regulated temperature and oxygen levels are also used on a large scale.

Animal Husbandry

Animal husbandry is the scientific management of animal livestock. It includes various aspects such as feeding, breeding, and disease control. As the population grows and living standards increase, the demand for milk, eggs, and meat is also rising. Animal husbandry is undertaken for several purposes:

• Milk Production: From cattle like cows and buffaloes.
• Egg and Meat Production: From poultry birds like chickens.
• Fish Production: Through capture and culture fishing.
• Honey Production: Through beekeeping or apiculture.
• Draught Labour: For agricultural work like tilling, irrigation, and carting.

Cattle Farming

Cattle husbandry is done for two purposes – milk production and draught labour for agricultural work. Indian cattle belong to two different species, Bos indicus (cows) and Bos bubalis (buffaloes). Milk-producing females are called milch animals (dairy animals), while the ones used for farm labour are called draught animals.

To improve milk production, we focus on the lactation period – the period of milk production after the birth of a calf. This can be enhanced by cross-breeding indigenous breeds with exotic ones.

• Indigenous/Desi Breeds: Examples include Red Sindhi and Sahiwal cows. These breeds show excellent resistance to diseases.
• Exotic/Foreign Breeds: Examples include Jersey and Brown Swiss. These breeds are selected for their long lactation periods.

Cross-breeding these two types can produce new varieties that have both desired qualities – high milk yield and high resistance to diseases.

Proper management of cattle is essential. This includes:

• Shelter: Well-designed, clean, and well-ventilated sheds to protect them from rain, heat, and cold.
• Feeding: The food requirements are of two types: (a) maintenance requirement, which is the food required to support the animal to live a healthy life, and (b) milk-producing requirement, which is the type of food required during the lactation period. Animal feed includes roughage (which is largely fibre) and concentrates (which are low in fibre and contain relatively high levels of proteins and other nutrients).
• Disease Control: Cattle suffer from a number of diseases which can cause death or reduce milk production. A healthy animal feeds regularly and has a normal posture. Both \texternal parasites (on the skin) and internal parasites (like worms) affect cattle. Vaccinations are given against major viral and bacterial diseases like foot and mouth disease and anthrax.

Poultry Farming

Poultry farming is undertaken to raise domestic fowl for egg production and chicken meat. Therefore, improved poultry breeds are developed and farmed to produce layers for eggs and broilers for meat.

• Layers: These are birds managed for the purpose of getting eggs.
• Broilers: These are birds raised for their meat. Their diet is rich in protein with adequate fat to facilitate rapid growth. They are marketed at 6-7 weeks of age.

The cross-breeding programmes between Indian (indigenous, e.g., Aseel) and foreign (exotic, e.g., Leghorn) breeds are focused on developing varieties with the following desirable traits:

• Number and quality of chicks.
• Dwarf broiler parent for commercial chick production.
• Summer adaptation capacity/tolerance to high temperature.
• Low maintenance requirements.
• Reduction in the size of the egg-laying bird with the ability to utilise more fibrous but cheaper diets.

Good management practices are important for good production. This includes maintenance of temperature and hygienic conditions in housing and poultry feed, as well as prevention and control of diseases and pests.

Fish Production (Pisciculture)

Fish is a cheap source of animal protein for our food. Fish production includes the finned true fish as well as shellfish such as prawns and molluscs. There are two ways of obtaining fish: from natural resources (capture fishing) and by fish farming (culture fishing).

Marine Fisheries

India’s marine fishery resources include 7500 km of coastline and the deep seas beyond it. Popular marine fish varieties include pomfret, mackerel, tuna, sardines, and Bombay duck. Marine fish are caught using fishing nets from fishing boats. Yields are increased by locating large schools of fish in the open sea using satellites and echo-sounders. Some marine fish of high economic value are also farmed in seawater. This is called mariculture. This includes finned fishes like bhetki and mullets, as well as shellfish like prawns and mussels, and oysters (for pearls).

Inland Fisheries

The water resources for inland fisheries include freshwater sources like canals, ponds, reservoirs, and rivers, and brackish water resources (where seawater and freshwater mix together), such as estuaries and lagoons. While capture fishing is also done in these waters, the yield is not high. Most fish production from these resources is through aquaculture.

Composite Fish Culture

A common and highly efficient method is the composite fish culture system. In such a system, a combination of five or six fish species is used in a single fishpond. These species are selected so that they do not compete for food among them as they have different types of food habits. For example:

• Catlas are surface feeders.
• Rohus feed in the middle-zone of the pond.
• Mrigals and Common Carps are bottom feeders.
• Grass Carps feed on the weeds.

As a result, the food available in all the parts of the pond is used. This increases the fish yield from the pond. One problem with this system is that many of these fish breed only during monsoon. A major problem in fish farming is the lack of availability of good-quality seed. To overcome this, ways have now been worked out to breed these fish in ponds using hormonal stimulation. This has ensured the supply of pure fish seed in desired quantities.

Bee-keeping (Apiculture)

Bee-keeping, or apiculture, is the practice of maintaining honey bee colonies, commonly in man-made hives. Honey is widely used and therefore bee-keeping for making honey has become an agricultural enterprise. Since bee-keeping needs low investments, farmers also use it as an additional income-generating activity. In addition to honey, the beehives are a source of wax which is used in various medicinal preparations.

The local varieties of bees used for commercial honey production are:

• Apis cerana indica, commonly known as the Indian bee.
• A. dorsata, the rock bee.
• A. florae, the little bee.

An Italian bee variety, Apis mellifera, has also been brought in to increase the yield of honey. This is the variety commonly used for commercial honey production because it has a high honey collection capacity, stings less, stays in a given beehive for long periods, and breeds very well.

The value or quality of honey depends upon the pasturage, or the flowers available to the bees for nectar and pollen collection. In addition to adequate quantity of pasturage, the kind of flowers available will determine the taste of the honey. Locations where bee colonies are kept are called apiaries or bee yards.

Important Questions and Answers

Question 1: What are the advantages of inter-cropping and crop rotation?

Answer:
Advantages of Inter-cropping:

• It helps to maintain soil fertility as the nutrient requirements of different crops are different.
• It saves time and labour as multiple crops can be sowed, irrigated, and harvested simultaneously.
• It ensures maximum utilisation of the nutrients supplied.
• It prevents pests and diseases from spreading to all the plants of one crop in a field.
• It reduces the risk of total crop failure.

• It helps in controlling pests and weeds. Many pests and weeds are crop-specific, and rotation disrupts their life cycle.
• It helps in replenishing soil nutrients. For example, planting legumes helps fix atmospheric nitrogen in the soil, which benefits the subsequent crop.
• It prevents soil depletion of a particular set of nutrients.
• It improves the overall soil structure and fertility, leading to higher long-term yields.

Question 2: What is the difference between broilers and layers and their management?

Answer:
Broilers and layers are two types of chickens raised in poultry farming for different purposes.
Broilers: These are chickens raised specifically for meat production. Their diet is protein-rich with adequate fat to encourage fast growth. They are typically ready for market in 6-7 weeks.
Layers: These are female chickens raised for egg production. They require a diet rich in vitamins, minerals, and micronutrients to support high egg-laying capacity.

Management Differences:

• Diet: Broilers need feed with high protein and fat for rapid weight gain. Layers need feed rich in calcium for strong eggshells and other nutrients for sustained egg production.
• Housing & Lighting: Layers require sufficient space and controlled lighting (about 15-16 hours a day) to stimulate and maintain egg production. Broilers are kept in conditions that restrict movement to conserve energy for growth.
• Purpose: Broilers are sold for meat after a short growth period. Layers are kept for a much longer period (about a year) until their egg-laying capacity declines.

Question 3: How do good animal husbandry practices benefit farmers?

Answer:
Good animal husbandry practices involve providing proper shelter, nutrition, breeding, and health care to livestock. These practices benefit farmers in several ways:

• Increased Yield: Proper feeding and care lead to higher production of milk, eggs, and meat, which directly increases the farmer's income.
• Improved Breed Quality: Scientific breeding programmes help in developing new breeds with desirable traits like high yield and disease resistance. This improves the overall quality and productivity of the livestock.
• Better Health and Lower Mortality: Proper sanitation, shelter, and regular vaccinations prevent diseases, reducing the mortality rate of animals and saving the farmer from potential losses.
• Efficient Resource Utilisation: Farmers can make better use of animal products and by-products. For instance, animal excreta can be used to make manure or biogas.
• Higher Economic Returns: Healthy and productive animals fetch a better price in the market, leading to enhanced economic stability for the farmer.

Question 4: What are the differences between manure and fertilizers?

Answer:
The main differences between manure and fertilizers are:

• Origin: Manure is a natural, organic substance derived from the decomposition of plant and animal waste. Fertilizers are commercially produced, synthetic chemical compounds.
• Nutrient Content: Manure is not very rich in specific nutrients but provides all essential nutrients in small quantities. Fertilizers are very rich in specific nutrients like N, P, and K.
• Soil Health: Manure adds humus to the soil, which improves its texture, water-holding capacity, and overall fertility. Fertilizers do not add humus and can degrade soil health over long-term use.
• Cost: Manure is generally inexpensive and can be prepared by farmers themselves. Fertilizers are costly and have to be purchased from the market.
• Environmental Impact: Manure is eco-friendly. Excessive use of fertilizers can lead to water and soil pollution.

Question 5: Explain composite fish culture. What is its main advantage?

Answer:
Composite fish culture is a method of fish farming where a combination of five or six different fish species are reared together in a single fishpond. The species are carefully selected based on their feeding habits so that they do not compete with each other for food. Instead, they utilize the food available in different zones of the pond.

For example, Catlas feed on the surface, Rohus are middle-zone feeders, Mrigals and Common Carps are bottom feeders, and Grass Carps feed on weeds. This ensures that all the natural food produced in the pond is effectively utilized.

The main advantage of composite fish culture is that it dramatically increases the fish yield from the pond. Since there is no competition for food and all parts of the pond's ecosystem are utilized, a much higher density of fish can be grown, leading to a significantly larger harvest and greater profitability compared to monoculture (rearing a single species).

Chapter Summary

Here are the key takeaways from our detailed exploration of 'Improvement in Food Resources':

• The increasing population necessitates improvements in food production efficiency from both agriculture and animal husbandry.
• Crop yield improvement is achieved through three stages: crop variety improvement, crop production improvement, and crop protection management.
• Crop variety improvement involves developing high-yield, disease-resistant, and better-quality varieties through techniques like hybridisation and genetic modification.
• Crop production management includes providing essential macro and micro-nutrients through manure and fertilizers, ensuring timely irrigation, and using effective cropping patterns like mixed cropping, inter-cropping, and crop rotation.
• Crop protection involves managing weeds, insect pests, and diseases, as well as proper storage of harvested grains to prevent losses.
• Animal husbandry is the scientific management of livestock for milk, eggs, meat, and other products.
• Cattle farming focuses on improving milch and draught breeds through cross-breeding and providing proper shelter, feed, and healthcare.
• Poultry farming involves raising layers for eggs and broilers for meat, with a focus on breed improvement and proper management.
• Fish production is done through capture fishing and culture fishing (aquaculture). Composite fish culture is a high-yield method that involves farming multiple non-competing species together.
• Bee-keeping (apiculture) is done for honey and beeswax, with the quality of honey depending on the available pasturage.