NCERT Solutions for Class 9th Science
Chapter 15 – IMPROVEMENT IN FOOD RESOURCES
(Complete Downloadable Chapter Solution PDF file is at the bottom of the page)
Q.1 What do we get from cereals, pulses, fruits and vegetables?
Ans Cereals – Carbohydrate
Pulses – Protein
Fruits and vegetables - A range of vitamins and minerals in addition to small amounts of proteins, carbohydrates and fats.
Q.2 How do biotic and abiotic factors affect crop production?
Ans Biotic factors can be defined as living components of the ecosystem with which an organism must interact. Various biotic factors such as diseases, insects and nematodes can reduce the crop production. For eg. pests can destroy or damage the crops, weeds (unwanted plants) which grow along the crop can take its nutrients and affect crop production. On the other hand abiotic factors are chemical and physical factors such as temperature, soil composition, and climate, along with the amount of sunlight, salinity, and pH which affect the crop yield. For eg. lower temperature and excessive soil salinity will reduce the crop yield, natural calamities like drought and flood are unpredictable and can destroy the whole crop.
Q.3 What are the desirable agronomic characteristics for crop improvements?
Ans Desirable agronomic characteristics for crop improvements are:
1) Tallness and profuse branching are desirable characters for fodder crops.
2) Dwarfness is desired in cereals, so that less nutrients are consumed by these crops.
Developing varieties of desired agronomic characters give higher productivity.
Q.4 What are macro-nutrients and why are they called macronutrients?
Q.5 How do plants get nutrients?
Q.6 Compare the use of manure and fertilizers in maintaining soil fertility.
Q.7 Which of the following conditions will give the most benefits? Why?
(a) Farmers use high-quality seeds, do not adopt irrigation or use fertilizers.
(b) Farmers use ordinary seeds, adopt irrigation and use fertilizer.
(c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.
Q.8 Why should preventive measures and biological control methods be preferred for protecting crops?
Q.9 What factors may be responsible for losses of grains during storage?
Ans Factors responsible for losses of grains during storage
1) Biotic factors: Insects, rodents, fungi, mites and bacteria etc.
2) Abiotic factors: Inappropriate moisture and temperatures in the place of storage.
These factors cause degradation in quality, loss in weight, poor germinability and discolouration of produce.
Q.10 Which method is commonly used for improving cattle breeds and why?
Ans Cross breeding is commonly used for improving cattle breeds.
The method of cross breeding helps in achieving an improved variety by using two good varieties of cattle. For eg. Exotic or foreign breeds (for example, Jersey, Brown Swiss) having long lactation periods can be cross-bred with local breeds (for example, Red Sindhi, Sahiwal) having excellent resistance to diseases to get animals with both the desired qualities.
Q.11 Discuss the implications of the following statement: “It is interesting to note that poultry is India’s most efficient converter of low fibre food stuff (which is unfit for human consumption) into highly nutritious animal protein food.”
Q.12 What management practices are common in dairy and poultry farming?
Q.13 What are the differences between broilers and layers and in their management?
Q.14 How are fish obtained?
Q.15 What are the advantages of composite fish culture?
Q.16 What are the desirable characters of bee varieties suitable for honey production?
Q.17 What is pasturage and how is it related to honey production?
EXERCISES
Q.1 Explain any one method of crop production which ensures high yield.
Ans Inter-cropping is one of the method of crop production which ensures high yield. Inter-cropping is defined as a method of growing two or more crops 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, soyabean + 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 belonging to one crop in a field. This way, the yield can be increased.
Q.2 Why are manure and fertilizers used in fields?
Ans Manure and fertilizers are used in fields to enrich soil with required nutrients. Manure (prepared by the decomposition of animal excreta and plant waste) helps in enriching soil with nutrients and organic matter and increases soil fertility.
On the other hand, fertilizers (commercially produced plant nutrients) supply nitrogen, phosphorus and potassium. They ensure good vegetative growth (leaves, branches and flowers) and give rise to healthy plants.
Manure and fertilisers should be used carefully and judiciously while aiming for optimum yields in crop production.
Q.3 What are the advantages of inter-cropping and crop rotation?
Q.4 What is genetic manipulation? How is it useful in agricultural practices?
Ans Genetic manipulation is a way of improving the crop by introducing a gene that would provide the desired characteristics. This results in genetically modified crops.
It is very useful in agricultural practices as it can help in resisting biotic and abiotic stresses. Genetic manipulation is useful in following ways:
1) Adaptability: These varieties can be grown in diverse climatic conditions and can tolerate high soil salinity etc.
2) High yield & improved quality: Genetic manipulation produces high quality crops and enhances productivity.
3) Reduced maturity duration: This can reduce the maturity period (sowing to harvesting) and thus increase the profitability of crop production.
4) Disease resistance: It helps in producing disease resistant crops.
Q.5 How do storage grain losses occur?
Q.6 How do good animal husbandry practices benefit farmers?
Q.7 What are the benefits of cattle farming?
Q.8 For increasing production, what is common in poultry, fisheries and bee-keeping?
Q.9 How do you differentiate between capture fishing, mariculture and aquaculture?