Class 9 Science Chapter 12 Question Answers - Improvement in Food Resources

Q1: What are manures? Give its classification.
Ans: Substance rich in organic matter and also supplies small quantities of nutrients to soil is called manure. Manure is classified based on the kind of biological material used to make it as :
(i) Compost,
(ii) Vermi-compost,
(iii) Green manure. 

• Compost : The manure prepared by decomposing farm waste, livestock excreta, plant waste, etc. in a pit is known as compost.
• Vermi-compost : When the above given matter is allowed to decompose in the pit along with some earthworms to fasten the process of decomposition is called vermi-composting. 
• Green manure : Some plants like sun-hemp are used to prepare manure by mulching them into soil by plough is known as green manure.

Q2: What are the various methods of irrigation in India?
Ans: Most of agriculture in India is rain-fed, several different kinds of irrigation system are adopted to supply water to agricultural lands. The resources are-wells, canals, rivers and tanks. 

• Wells : Dug wells and tube wells. In dug wells water is collected from water— bearing strata. 
• Tubewells : Water from deeper strata. 
• Canals : Most extensive irrigation system. Canals receive water from reservoirs or rivers. The main canal is divided into branch canals having further distributaries to irrigate fields.
• River lift system : Water is directly drawn from the river 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.

Q3: What are the different patterns of cropping? 

What are the different cropping systems?
Ans: Different systems of growing crop : 

• Mixed cropping : Two or more crops grow simultaneously on the same piece of land, is called mixed cropping.  
  Example : Wheat + grain, wheat + mustard.
• Inter-cropping : It is a method of growing two or more crops simultaneously on the same field in a definite pattern. A few row of one crop alternate with a few rows of second crop.  
  Example : Soyabean + Maize or Bajra + Lobia.(
• Crop rotation : The growing of different crops on a piece of land in a succession is known as crop rotation.

Q4: What are weeds? How can we control them? Give different methods of weed control.
Ans: Unwanted plants which grow along with crops are called weeds. Weeds compete with crops for natural resources; like sunlight, water and nutrients. Thus, weeds hamper the growth of crops. Weeds are usually removed manually by hands and by sickles. This process is called weeding. Sometimes, weedicides are also sprayed to kills weeds.
Weeds can be controlled by different methods :

• Weedicides : These are the chemicals sprayed on the weeds to kill them. Excessive use is poisonous and causes environmental pollution. 
• Mechanical removal : In this method weeds are uprooted by removing manually or by machines.
• Preventive methods : Proper seed bed preparation, timely sowing of crops, intercropping and crop rotation helps in weed control.

Q5: What are the factors for which variety improvement of crop is done?
Ans:

• Higher yield : It increases production of crop. 
• Biotic and abiotic resistance : Crop should be resistant to biotic factors like diseases, insects, pests and abiotic factors like drought, salinity, heat, etc. 
• Change in maturity duration : Short-duration maturity allows farmer to grow more crops in a year with short duration maturity and reduces the crop production cost. 
• Wider adaptability : Crop should be able to adapt to changing environmental conditions. 
• Desirable agronomic characteristics : Crop should have tallness and dwarfness as per need. Dwarfness is required for cereals, so that few nutrients are consumed.

Q6: Large amount of food grains get spoiled every year in India due to improper storage of food grains. How can this be avoided?
Ans: Food grains get spoiled by insects, fungi, rodents, bacteria, moisture at the place of storage.
Storage losses can be reduced by taking some preventive and control measures. 

• The seeds that are to be stored should be dry
• The grains should be cleaned.
• The grains should be fumigated using chemicals that kills pest.
• The storage houses should be waterproof.
• The grains should be stored in sealed gunny bags.
• The bags should be kept few centimetres away from the wall.
• The walls and the floor should be water-proof with no holes in it, to avoid rodents, pests.

Q7: Explain different types of fisheries.
Ans: The different types of fisheries are marine fisheries; inland fisheries, capture fishing, mariculture and aquaculture.

• Marine fisheries : Marine fishes are caught using fishing nets. 
• Mariculture : Marine .fishes are cultured in seawater. 
• Inland fisheries : The fisheries done in freshwater resources like canals, ponds, reservoirs and rivers. 
• Capture fishing : It is done in sea-water, estuaries and lagoons. 
• Aquaculture : Culture of fish done in different water bodies is called aquaculture.

Q8: What are the practices used for dairy industry?
Ans: The practices used for dairy industry to get the optimum yield are : 

• Shelter : The shelter should be clean, spacious and airy. (
• Feeding : Proper food at proper time is essential for dairy animals. 
• Rearing of animals : Providing them proper health care and protection from pathogens, diseases and proper vaccination. 
• Breeding : The crossing of different variety of milch animals to obtain a breed that can produce more yield of milk.

Q9: Write a paragraph in your own words on each of the following.
(a) Preparation of soil,
(b) Sowing,
(c) Weeding,
(d) Threshing
Ans:
(a) Preparation of soil : Preparation of soil is the first step of farming. Soil is loosened and turned over. This helps in making the soil more airy so that roots can breathe in air. Moreover, loosening of soil also facilitates better penetration of roots into the soil. Seeds can be easily sown in loosened soil.
(b) Sowing : The method of putting the seeds into soil is called sowing. Traditionally, seed is sown manually by spreading the seeds by hands. This process is called broadcasting. Seed drills are used when sowing needs to be done on a large scale.
(c) Weeding : Removal of weeds is called weeding. Unwanted plants which grow along with the crop are called weeds. They compete for resources; like sunlight, water and air; with the main crop. So, it is necessary to remove weeds for proper growth of crops. Weeding is usually done manually by using hands and sickles. Sometimes weedicides are also sprayed.
(d) Threshing : Separation of grains from harvested stems is called threshing. For smaller quantity, threshing is done by hands. For somewhat bigger quantity, threshing is done using animal; especially bullocks. Animals are made to trample over the harvested stock which helps in separation of grains. Threshing machines are used for bigger quantities.

Q10: If wheat is sown in the kharif season, what would happen? Discuss.
Ans: The crop of wheat needs mild to moderate temperature and frost free days; along with irrigation but no water logging. Winters are suitable for growing wheat. In the kharif season; which coincides with the peak summer months in India, temperature is at its peak which is not suitable for wheat. Moreover, during rainy season lot of water accumulates in fields which would be harmful for wheat crop. Hence, if wheat is sown in the kharif season; the productivity would be minuscule and would not be profitable for the farmers.

Q11: Give brief sketch on advantages and disadvantages on manure and fertilizers.
Ans:
Advantages of manure 

• It increases the number of friendly microbes. 
• It improves the texture of soil by adding organic matter (humus). 
• It increases soil fertility, water holding capacity and aeration. 
• It reduces soil erosion. 
• It is cheap.

Disadvantages of manure

• They have fewer amounts of nutrients as compared to fertilizers.
• Manures are bulky and not easy to store and transport.

Fertilizers : These are commercially manufactured inorganic salts containing one or more essential plant nutrients like NPK, which are used to increase soil fertility.
Advantages of fertilizers

•  They are nutrient specific and required in small amounts. 
• They are water soluble and absorbed by the plant easily. 
• They are easy to store and transport. 

Disadvantages of fertilizers

• Fertilizers can change the soil structure by killing the soil microbes. 
• Fertilizers can change the chemical composition of soil. 
• Accumulation of fertilizers in water bodies causes eutrophication.