NCERT Solutions for Class 8th Science
Chapter 1. Crop Production And Management
- Plants of the same kind are grown and cultivated at one place on a large scale, it is called a crop.
- Khurpi, sickle, shovel, plough, etc. are some agricultures tools.
- Crops are of different types like cereals, vegetables and fruits.
- According to season there are two type of crops – (i) Rabi crops and (ii) Kharif Crops.
- Rabi crops are wheat, gram, pea, mustard and linseed.
- Paddy, maize, soyabean, groundnut, cotton, etc., are kharif crops.
- The process of loosening and turning of the soil is called tilling or ploughing.
- The levelling of soil is done with the help of a leveller.
- Nowadays ploughing is done by tractor driven cultivator.
- The use of cultivator saves labour and time.
- The substances which are added to the soil in the form of nutrients for the healthy growth of plants are called manure and fertilisers.
- Manure is an organic substance obtained from the decomposition of plant or animal wastes.
- Rhizobium bacteria are present in the nodules of the roots of leguminous plants.
- Rhizobium bacteria fix atmospheric nitrogen.
- A fertiliser is an inorganic salt which is prepared in factories.
- Fertilisers are very rich in plant nutrients like nitrogen, phosphorus and potassium.
- The supply of water to crops at different intervals is called irrigation.
- The sources of irrigation are— wells, tubewells, ponds, lakes, rivers, dams and canals.
- The traditional ways of irrigation are moat, chain pump, Dhekali and Rahat.
- Modern methods of irrigation help us to use water economically.
- Modern methods of irrigation are sprinkler system and drip system.
- These undesirable plants are called weeds.
- The removal of weeds is called weeding.
- Weeds are also controlled by using certain chemicals, called weedicides, like 2,4-D.
- The cutting of crop after it is mature is called harvesting.
- The grain seeds need to be separated from the chaff. This process is called threshing.