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Why do we store food material at low temperatures?

We store food materials at low temperatures because, it prevents food from spoilage by enzymes and bacteria.


Why does boiled rice get more easily spoiled than raw rice?

The percentage of water in boiled rice is higher. Therefore, it gets spoiled easily due to the action of microorganisms, which multiply fast in moisture.


State any two factors, which have helped us to raise the food production.

The two factors, which have helped us raise food production are,
(i) Use of high yielding varieties.

(ii) Use of fertilizers, manures, crop rotation and leaving the land fallow.


Describe the role of water in crop production.

Crops should be irrigated properly to get better production. Water helps the plants in germination of seeds and plant growth. Water acts as a solvent for dissolving nutrient and mineral salts present in the soil. This solution is then absorbed by the roots and transported to other parts of the plant. Water pressure in plant tissues provides the firmness that supports the plants.


What is fumigation?

Fumigation is a process, whereby the stored food grains gets disinfected by the fumes of certain chemicals. The chemicals used for fumigation are known as fumigants.


What are weeds? How are they removed?

Weeds are undesirable plants, which grow along with crop plants in the field. Since, they compete with crop plants for space, light, water and nutrients, it is essential to ensure that they are removed from time to time. Their removal from the field is called weeding. It can be done either manually by pulling them out or by applying some chemical called weedicides.


Mention the essential features of good storage.

The essential features of good storage are as follows:
(i) It should be water proof, easy to clean, free from moisture.

(ii) It should be unaffected by variation in temperature and humidity.

(iii) It should be free from the entry of birds and rodents.

(iv) It should be far from slaughter houses, garbage dumps, tanneries, chemical industries and bone crushers.


Enlist the functions of manures.

The functions of manures are listed below:
(i) Provides humus to the soil.

(ii) Improves texture and chemistry of soil.

(iii) Removes general deficiency of the soil.

(iv) Retains water in the soil.

(v) Prevents soil pollution.

(vi) Crop products are pollution free.

(vii) Provides elements/nutrients to the soil that are essential for plant growth.


What is meant by infestation?

When microorganisms and insects, settle in food items, the food gets spoiled. This is called infestation.


What is pasteurization?

Pasteurization is a modern processing method to preserve milk by heating it at 70° C for half an hour.


An agriculture worker talking to the farmer said, " For obtaining good wheat crop the use of fungus resistant seeds and irrigation after the maturity of crops are needed." Which part of the statement is not correct?

"Irrigation after the maturity of crops are needed". This part of the statement is incorrect. Irrigation should be done before maturity of the seed.


Name one solid fumigant.

Aluminium phosphide is a solid fumigant.


Name few cereals. Why do we consume them?

Wheat, rice, maize, millets and sorghum are some of the cereals. These provide carbohydrate that gives us energy


Why are fertilizers used in agriculture?

Fertilizers are used in agriculture because repeated growing of the crops deplete the nutrients of soil. Fertilizers provide the nutrients, most necessary for general growth of plants. They increase the fertility of the soil and enhance the crop yield.


How would you control the insects and microorganisms in food grains?

Pesticides are used for controlling pest. They are either applied by spraying or by fumigation. Malathion and pyrethrum are common pesticides. Fumigation is a better method. Fumigants consist of volatile chemicals, which quickly vapourise and kill the insects without affecting the grain. Ethylene dibromide and aluminium phosphide as well as copper oxychloride are the two common fumigants.


How do weeds affect the growth of crops?

Weeds affect the growth of crops by competing with crop plants for water, space, nutrients and sunlight. Thus, the crop yield is reduced. Some of the weeds are alternate hosts of pathogens in their life cycle. Thus, they provide shelter to them and promote plant diseases. Their seeds mix with the food grain and lower the quality of food grain yield.


Patches of white powdery material are seen on the bags of wheat stored in a godown. What does it indicate?

The patches of white powdery material seen on the bags of wheat stored in a godown indicate that the wheat stored in godown is infested by insects and micro-organisms.


State the factors, which have helped us to raise food production.

The factors, which have helped us to raise food production are,
(i) The use of high yielding varieties of crop.

(ii) Proper and timely irrigation.

(iii) The use of fertilizers, manures, crop rotation, leaving fallow raise the fertility of soil.

(iv) The protection of crops from pests and diseases.


Which one of the following crops would require a minimum quantity of NPK or urea for its proper growth?
Cabbage, sugarcane, wheat, soyabean.

Soyabean is the one that requires a minimum quantity of NPK or urea for its proper growth.


Name one biotic and abiotic factor, which is responsible for the damage of stored food grains.

The biotic and abiotic factors responsible for the damage of stored food grains are,
(i) Biotic factors – Rodents, insects, bacteria, fungus, etc.
(ii) Abiotic factor – Temperature, moisture, etc.


A farmer grows maize crop in a field year after year. He finds that the yield becomes low. Give one possible reason for it.

The soil becomes depleted in nitrogen and those nutrients, which had been utilized by that crop. This lowers the fertility of the soil. Therefore, the yield becomes low.


What are the characteristics, which are expected to be available in the seeds of improved varieties?

The characteristics of improved varieties of seeds are as follows:
(i) The seeds should be photo and thermosensitive. Insensitivity affects the cultivation of the crops.

(ii) High yielding property.

(iii) Capacity to grow in almost all seasons.

(iv) Resistant to pests and diseases.

(v) Mature in a shorter period.


Why is soil replenishment essential?

By growing the same crop year after year in the same soil/field, the soil gets depleted of certain nutrients. This results in a drop in crop yield every year. Hence, soil replenishment is essential.


The fields, in which legumes are grown get enriched with nitrogen. Why?

The roots of legumes have nodules, which fix free nitrogen and converts it into nitrates. This makes the field fertile. Therefore, legumes are grown in a season alternating between cereal crops such as wheat and millet.


What is mixed cropping? What are its advantages?

The growing of more than one crop in the same field is known as mixed cropping.
Advantages of mixed cropping:
(i) It improves the fertility of soil and hence, increases the crop yield.

(ii) It saves the time and labour of farmers.


Define crop rotation.
Crop rotation is the practice of growing a series of different types of crops in the same area in sequential seasons.
Crop rotation gives various nutrients to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals and other crops. Crop rotation also mitigates the build-up of pathogens and pests that often occurs when one species is continuously cropped, and can also improve soil structure and fertility by alternating deep-rooted and shallow-rooted plants. Crop rotation is one component of polyculture.


Enlist two factors that helped us to raise food production.

The two factors that helped us to raise food production are,
(i) Use of chemical fertilizers.

(ii) Crop rotation and mixed cropping.


Mention any three advantages of hybrids.

The three advantages of hybrids are as follows:
(i) Plant yield in high.

(ii) It takes less time for maturing.

(iii) They have wide adaptability.


What do you mean by varietal improvement?

Varietal improvement means introduction of new varieties of crop plants in our country. These varieties have good yield. They are diseases resistant. It is done by cross breeding and selection. It forms the backbone of modern agriculture.


What are the advantages of multiple cropping?

The advantages of multiple cropping are as follows:
(i) It saves time and labour of the farmer.

(ii) Increases crop yield.

(iii) Improves soil fertility.

(iv) Optimum utilization of the soil.
(v) Avoids exhaustion of soil element or nutrients.


A farmer grows grain crops between two cereal crops. Which agricultural practice is he following?

The farmer is following crop rotation.


Name the major group of activities for improving crop yields

Crop variety improvement
Crop production improvement
Crop protection management


What is the requirement of high yielding varieties?

The high yielding variety plants require more water and fertilizers. They require frequent weeding and continuous use of pesticides and fungicides.


What do you mean by varietal improvement?

Varietal improvement means introduction of new varieties of crop plants in our country. These varieties have good yield. They are disease resistant. It is done by cross breeding and selection. It forms the backbone of modern agriculture. Plant breeders get this by hybridization.


Name the scientist who introduced Mexican variety of wheat in India.

N.E. Borlaug is the scientist who introduced Mexican variety of wheat in India.


Mention a crop that would enrich the soil with nitrogen.

Pea plant is one such that enriches the soil with nitrogen.


Why are legumes desirable in crop rotation?

Legumes are desirable in crop rotation because these plants have nodules on their roots, which enrich the soil and increase the nitrogen content in it. The root nodules contain the bacteria Rhizobium, which are capable of fixing the atmospheric nitrogen.


What is food and fodder system?

Food crops and fodder crops are grown together in the same field. Maize, rice and wheat are grown along with berseem, oat and sorghum, etc.


What do you mean by agro forestry system.

It is a collective name for land-use systems and technologies where, woody perennials are deliberately used on the same land management unit like agricultural crops and animals, either in some form of spatial arrangement.


Define sustainable agriculture.

Sustainable agriculture is the method of growing crops and raising livestock based on organic fertilizers, soil conservation, water conservation and biological control of pests and minimal use of non-renewable fossil-fuel energy.

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