CBSE Guess - 8th NCERT Science, Crop Production and Management – long answer questions

 


Class 8 NCERT Science - Chapter 1, Crop Production and Management

NCERT Guide - CBSE Guess and Guide

 


Solutions of CBSE Guess Questions (4-5 marks questions)

Question.1: Write a paragraph on the various methods used to replenish the nutrients in the fields.

Solution: When crops are grown in the fields, they use all the nutrients present in the soil. These nutrients have to be replenished for the further cropping. Various methods and products are used for this purpose.

Fertilizers: Fertilizers are the chemicals which replenish the soil with all the nutrients. They are produced in the factories and are inorganic products. Every fertilizer is rich in a particular nutrient. Some examples of fertilizers are urea, ammonia sulphate, potash, NPR etc. They help in getting better and healthy yields. But, excessive use of these chemicals is also harmful.

CBSE Guess - 8th NCERT Science, Crop Production and Management – crop threshingManure: Manures are the organic products, which are obtained by the processing of dead bodies of plants and animals. Dead bodies of plants and animals are dumped in pits. They get decomposed to become manure. Using manure not only improves the texture of the soil but also, improves the water holding capacity of the soil.

Fallowing: Sometimes continuous growing of crops makes the soil barren or infertile. It needs to be left uncultivated so that it can regain its nutrients and fertility. This process of leaving soil uncultivated for one crop season is called fallowing.

Crop RotationIf the same crop is grown in the field year after year, it will lead to the deficiency of certain minerals. It is due to this fact that the same crop requires same type of nutrients. To solve this problem farmers are encouraged to grow one pulse crop in – between two cereal crops in the field. So the method of successive cultivation of different crops in an orderly manner on the same fields, in contrast to a one-crop-system or to haphazard crop successions is known as crop rotation. For example, growing legumes as fodder in one season and wheat in the next season. The roots of legumes have so many nodules which contain nitrogen fixing bacteria. These convert free atmospheric nitrogen into nitrates and increase the fertility of the soil. (Replenishing of soil with nitrogen)

Question.2: Write a short note on Threshing & Winnowing.

Solution: When a farmer cut his crops, he has to separate the grain seeds from chaff. This process is called threshing. Mechanically it can be done with the help of threshers and combine. Farmers with small holdings of land do the separation of grain and chaff by winnowing. The grains are thrown from the height in the direction of air. The air carries away the lighter chaff or dried stems and leaves and the heavier grain drop down in the form of a heap. This whole process is called winnowing. 

More Study  

ü  Crop Production and Management - 8th NCERT Science - Solutions of CBSE Guess Questions (Objective, Fill in the Blank, MCQ, Short answer types)

ü  CBSE 8th NCERT Science Guide (all chapters)


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