CBSE Class 9 Science Improvent in Food Resources Worksheet Set A

Question. What is crop variety improvement?
Answer : Crop variety improvement is the technique of bringing together various useful characters from different varieties of the same or different varieties of crop plants into one crop variety.

Question. How do biotic and abiotic factors affect crop production?
Answer : Factors responsible for loss of grains, during storage and production are:
(a) Biotic factors like rodents, pests, insects, etc.
(b) Abiotic factors like temperature, humidity, moisture, etc. Combination of both biotic and abiotic factors causes:
(i) infestation of insects
(ii) weight loss
(iii) poor germination ability
(iv) degradation in quality
(v) discolouration
(vi) poor market price

Question. What are the desirable agronomic characteristics for crop improvements?
Answer : Desirable agronomic characteristics for crop improvements are:
(a) Tallness and profuse branching are desirable characters for fodder crops. (b) Dwarfness is desired in cereals, so that less nutrients are consumed by these crops.

Question. What do you mean by hybridization?
Answer : Hybridization refers to crossing between genetically plants. This crossing may be intervarietal (between different varieties), interspecific (between two different species of same genus) or intergeneric (between different genera).

Question. What is genetic manipulation? How is it useful in agricultural practices?
Answer : Genetic manipulation is a process of incorporating desirable (genes) characters into crop varieties by hybridisation. Hybridisation involves crossing between genetically dissimilar plants. This is done for production of varieties with desirable characteristics like profuse branching in fodder crops, high yielding varieties in maize, wheat, etc. Genetic manipulation is useful in developing
• Increased yield
• Better quality
• Shorter and early maturity period
• Better adaptability to adverse environmental conditions
• Desirable characteristics

Question. Differentiate between manure and fertilizer?
Answer : 

Question. What is organic farming and write its advantages?
Answer : Organic farming is an alternative method of production of crops and livestock without the use of harmful chemical pesticides, fertilisers, growth hormones, etc.
Some of the methods used in organic farming are the usage of green manures, mechanical cultivation, crop rotation, etc.
The advantages are as follows:
1. Eco-friendly and produce healthier crops as natural methods are employed.
2. Helps in saving energy.
3. The fertility of the soil is conserved

Question. What is irrigation?
Answer : Irrigation is timely supply of water to the crops through human efforts from sources other than rain.

Question. Name two modern methods of irrigation?
Answer : 1. Drip irrigation
2. Sprinkler irrigation.

Question. Write a note on crop rotation?
Answer : Crop rotation:
The practice of growing different crops on the same piece of land in a preplanned succession is called crop rotation.
Depending upon the duration, crop rotation is classified as:
One-year rotation: Rice-Wheat, Maize-Mustard
Two-year rotation: Maize-Mustard-Sugarcane-Fenugreek, Maize-Potato Sugarcane-Pea
Three-year rotation: Cotton-Sugarcane-Pea-Maize-Wheat, Rice-Wheat-
Mung-Mustard-Sugarcane-Berseem Advantages of crop rotation:
1.Fertility of soil maintained for longer period.
2.The chemical nature of soil is not altered.
3.It helps in weed and pest control
4.It saves a lot of nitrogen fertilizers

Question. List various methods of weed control.
Answer : Methods of weed control are-
1. Mechanical methods- Weeds are removed by pulling out by hand or by using a khurpa, hoe.
2. Cultural method- It include proper seed bed preparation timely sowing of seeds, intercropping along with suitable rotation.
3. Chemical methods – weeds can be controlled by the use of chemicals like 2, 4
4. Biological methods –insect of other organism of used plants is used to attack the weeds and reduce their number.

Question. State any two controls measures to be taken before grains are stored
Answer : Prevention measures:
(a) Strict cleaning of the produce before storage.
(b) Fumigation should be done to kill pest.

Question. What is sustainable agriculture?
Answer : Sustainable agriculture is the successful and judicious use of natural resource for higher production without disturbing the quality of our environment and conserving natural resources.

Question. what do you mean by fumigation?
Answer : Those pesticides which can destroy insects by forming toxic fumes are called fumigants and process of their use is called fumigation. Fumigants may be solid, liquid or gaseous. Examples:
Aluminium phosphate (solid fumigant)
Ethylene dichloride-carbon tetrachloride (EDCT) (liquid fumigant)
Methyl bromide (gaseous fumigant)

Question. What is pest and how it can be control?
Answer : Insect pests attack the plants in three ways:
(a) They cut the root, stem and leaves (Chewing insects).
(b)They suck the cell sap from various parts of the plants (Sucking insects).
(c)They bore into the stem and fruits (Internal feeders).

Preventive measures
1.By using pesticides: The chemical used to eliminate pests are called pesticides. Pesticides include insecticides (for killing the insects), weedicides (for killing the weeds), rodenticides (for killing rats), and fungicides (for killing the fungi).
2.By using natural insecticides: Like neem

HOME ASSIGNMENT
Q.1Define macronutrient and micronutrient? Write one example of each.
Q.2 Why should the pesticides be used judiciously?
Q.3 What are weeds? Give 2 examples. Why is the removal of weeds necessary from the cultivated field?
Q.4 What are weedicides? Give two examples.