CLASS 8 SCIENCE Ch 1: CROP PRODUCTION AND MANAGEMENT

 CLASS 8 SCIENCE Ch 1: CROP PRODUCTION AND MANAGEMENT

Ans: 1.

(a) The same kind of plants grown and cultivated on a large scale at a place is called a crop.

(b) The first step before growing crops is preparation of the soil.

(c) Damaged seeds would float on top of water.

(d) For growing a crop, sufficient sunlight and nutrients and water from the soil are essential.

Ans: 3

(a) Examples of Kharif crops are paddy and maize.

 (b) Examples of Rabi crops are wheat and mustard.

Ans: 4

(a) Preparation of soil: Preparation of soil refers to the process of loosening and turning the soil to make it suitable for the growth of crops. This involves ploughing, levelling, and adding manure or fertilisers to the soil.

(b) Sowing: Sowing is the process of planting seeds in the soil for growing crops. This is done either manually or using machines like seed drills.

(c) Weeding: Weeding involves removing unwanted plants, i.e., weeds, from the crop field. This is done manually or using tools like a hoe.

 (d) Threshing: Threshing is the process of separating grains from the harvested crop. This is done by beating the crop or using machines like a thresher.

Ans: 5

Fertilisers are different from manure in that fertilisers are chemical substances that are artificially made to provide nutrients to the soil and enhance plant growth. They are available in concentrated forms and are easy to apply. On the other hand, manure is organic matter that is obtained from decomposed animal waste, crop residue, or compost. It is an excellent source of nutrients and helps to improve soil fertility.

Ans: 6

Irrigation refers to the process of supplying water to crops to support their growth. Two methods of irrigation that conserve water are drip irrigation and sprinkler irrigation. In drip irrigation, water is slowly dripped directly to the plant roots, thereby reducing water loss due to evaporation or runoff. In sprinkler irrigation, water is sprayed in a controlled manner over the crop field, which also helps to reduce water loss.

Ans: 7

Wheat is a Rabi crop, which means it is typically grown during the winter season. If it is sown in the kharif season, it will not be able to grow properly as it requires cool temperatures and low humidity for proper growth. Additionally, the monsoon rains during the kharif season can lead to waterlogging and damage to the wheat crop.

Ans: 8

Continuous plantation of crops in a field can lead to soil depletion, erosion, and loss of nutrients. This is because crops absorb nutrients from the soil, and if the same crop is grown repeatedly, the soil becomes depleted of those nutrients. This can be prevented by practising crop rotation, where different crops are grown in the same field in different seasons, or by adding manure or fertilisers to the soil.

Ans: 9

Weeds are unwanted plants that grow in the crop field and compete with the crop for resources like water and nutrients. They can be controlled by using manual methods like hand weeding or using tools like a hoe. Weeds are also controlled by using certain chemicals, called weedicides