Why should preventive measures and biological control methods be preferred for protecting crops Chapter 15: Improvement in Food Resources Science Class 9 solutions are developed for assisting understudies with working on their score and increase knowledge of the subjects. In text questions of page no 209 is solved by our expert teachers. You can get ncert solutions and notes for class 9 chapter 15 absolutely free. NCERT Solutions for class 9 Science Chapter 15: Improvement in Food Resources is very essencial for getting good marks in CBSE Board examinations
In text questions of page no 209
Ans: Sometimes crops are very much affected or destroyed by the weeds, insects pests and diseases. For example
(i) Weeds compete for food, space and light. They use the nutrients from the soil and reduce the growth of the crop.
(ii) Insect pests affect the health of the crop and reduce its yield.
(iii) The pathogens like bacteria, viruses and fungi cause the disease in the plants. Therefore they must be controlled by using suitable preventive masures.
Q. No. 2: What factors may be responsible for losses of grains during storage?
Ans: During the storage of grains both biotic and abiotic factors cause losses to the grain. Biotic factors such as insects, rodents, mites, fungi, bacteria, etc. and various abiotic factors such as moisture, temperature, lack of sunlight, etc. are responsible for losses of grains.
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