NCERT Solutions for Class 9 Science Chapter 12 : Improvement in Food Resources

Fishes are obtained in two ways:

Capture fishing: Obtaining fish from natural resources.

Culture Fishery: Culturing of fishes in freshwater ecosystems, like rivers, ponds and lakes, also including marine.

Pasturage refers to the availability of flowers to the bees for easy accessibility for pollen collection and nectar. The kinds of flowers available will determine the taste of the honey; hence, Pasturage is the main reason for good quality honey.

For increasing production, cross-breeding techniques are used adopted in poultry, fisheries and bee-keeping. Along with these techniques, regular and proper maintenance methods are useful in improving production.

Cereals are the source of carbohydrates and are the main source of energy.

Pulses provide protein for growth and development.

Vegetables and fruits are loaded with minerals, vitamins, carbohydrates, proteins and fats for overall development.

The essential agronomic features required for crop improvement are:

• Profuse branching along with tallness in any fodder crop.

• Dwarfness in any cereals.

There are 16 basic essential nutrients required by plants to grow. Carbon and Oxygen are supplied by water, and the remaining nutrients are supplied through the soil.

Option (c) will give the most benefits because the use of good quality seeds is not only sufficient until the soil is properly irrigated, enriched with fertilisers and protected from biotic factors.

2 major factors that affect the crop are:

• Biotic factors like insects, rodents, pests, and many more spread the disease and reduce crop production.

• Abiotic factors like humidity, temperature, moisture, wind, rain, flood and many more destroy the crop raised.

Macro-nutrients are the fundamental elements that are used by plants in more quantity. Macro-nutrients needed by the plants are

• Macro-nutrients as the constituent of protoplasm.

• Phosphorus, Nitrogen, and Sulphur are present in proteins.

• Calcium exists in the cell wall.

• Magnesium is a significant component of chlorophyll.

• Manure improves soil quality with added nutrients.

• Manure provides extra organic matter called humus to the soil and therefore increasing the water retention capacity of sandy soils and drainage in clayey soil.

• Manures reduce soil erosion.

• They provide food for soil-friendly bacteria, which are helpful in growing crops.

The effects of fertilisers are

• Fertilisers make the soil become too dry and powdered and raise the rate of soil erosion.

• The organic matter decreases by decreasing the porosity of the soil; hence, the plant roots do not get oxygen properly.

• The nature of soil changes, either basic or acidic.

Over-exposure to chemicals leads to environmental problems; hence, biological methods are preferred for protecting crops from pathogens, insects and rodents, along with increasing production. Since chemicals are harmful to plants and also to the animals which feed on them, bio-pesticides are used as a safe way of crop protection.

Biotic and Abiotic factors are responsible for the loss of grains during storage like

• Rodents

• Pests

• Insects

• Fungi

• Bacteria

• Sunlight

• Flood

• Rain

• Temperature

• Moisture

Cross-breading is generally the best method adopted for improving cattle breed quality. In this method, breeding between two good cattle breeds results in a new, improved variety of cattle breeds or offspring. While breeding, care is taken to have a good resultant with a high yield having resistance to climatic conditions.

• Well-designed Hygienic shelter for dairy animals and poultry birds.

• Good quality proper food and fodder are provided to dairy animals and poultry birds.

• Importance for animal health by prevention and cure of disease caused by bacteria, viruses, or fungi.

• Sunlight-feasible and airy ventilated shelter for animals.

Broilers

The poultry bird raised for meat purposes is called a broiler. Broilers feed on protein-rich adequate-fat food. The level of vitamins A and K is kept high in poultry feeds.

Layers

The egg-laying poultry bird is called a layer. The housing, environmental and nutritional requirements of broilers vary from those of egg layers. Layers require proper lighting and enough space.

Poultry farming aims to raise domestic birds for egg and chicken meat purposes. These domestic birds feed on animal feeds which mainly consist of roughages for getting good quality feathers, eggs, chicken and nutrient-rich manure. For these reasons, it is said that “poultry is India’s most efficient converter of low-fibre foodstuff into highly nutritious animal protein food.”

The advantages of composite fish culture are

• In a single fish pond, a combination of 5 or 6 types of fish species can be cultured since they do not compete for food among themselves

• Food resources can be completely utilised

• Survival of the fish also increases

• More yield

• The variety of bees should yield a large amount of honey.

• The bees should stay for a longer period in bee hives.

• The bees should not sting much.

• Bees should be disease resistant.

Plant breeding is one of the methods adopted for high-yield plant breeding and is implemented to improve the varieties of crops by breeding plants. Plants from various places/areas are picked up with preferred traits, and then the process of hybridisation or cross-breeding is done among these diversities to get a crop/plant of anticipated characteristics.

Manures and fertilisers are used to enrich the soil quality and improve the yield. They also help in controlling diseases. Manure and fertilisers replenish the soil by supplying nutrients to the soil. They are excellent sources of potassium, phosphorous and nitrogen which assist in the healthy development of plants. Manures and fertilisers mainly improve the fertility of the soil.

Inter-cropping

• Checks pests and rodents and hence decreases the chances of the spoiling of whole crops

• Decreased chances of soil erosion

• Reduced loss of crops with high yield

• Less water requirement

Crop rotation

• Farmers can grow two or three crops annually

• Pulses take nitrogen directly from the atmosphere and hence require a minimal amount of fertilisers

• Both fruits and vegetables can be grown easily

• Best use of land with a proper supply of nutrients

Genetic manipulation is a process in which the transfer of genes takes place from one organism to another. Here, a gene of a particular character is introduced inside the chromosome cell, resulting in a transgenic plant.

Example: BT Cotton is a genetically modified crop which carries bacterial genes that protect this plant from insects. These are used in plants like brinjal, cabbage, rice, cauliflower, and maize crops to get protection from insects.

Storage grain losses occur due to various abiotic and biotic factors.

Abiotic factors

• Humidity

• Air

• Temperature

• Flood

• Wind

Biotic factors

• Insects

• Rodents

• Pesticides

• Bacteria

• Mites

• Birds

Good practice of animal husbandry benefits farmers in the following ways:

• Yields in good quality cattle

• Better quality of milk production

• Use in agriculture for carting, irrigation and tilling

The benefits of cattle farming are

• Cattle are used for agricultural purposes

• Generation of good quality cattle

• Milking and meat purpose

• The skin of cattle is used for the leather and wool industry

Capture fishing: It is a technique in which fish are captured from various sources of natural resources like sea, rivers, lakes and ponds.

Mariculture: Culturing of fish in marine fishes like prawns, oysters, bhetki and mullets in marine water for commercial use.

Aquaculture: Involved in culturing of fish in both marine and freshwater.