Crop Production and Management Question Answers: NCERT Class 8 Science

(a) Crop

Crop may be defined as the same kind of plants that are grown on the large scale.

(b) Preparation

Before growing crops, preparation of soil is done. In this process, turning and loosening steps of the soil is done. It allows the roots to penetrate deep into the soil.

(c) Float

The damaged seeds are light in weight. That is why they float on water whereas the fresh seeds are heavy in weight so they easily settle down in the bottom.

(d) Water and nutrients

For a health crop, we need a proper sunlight, water and nutrients. If the deficiency of these things occurs then the crop should be weak.

The boxes can be arranges in the following order to make a flow chart of sugarcane crop production:

• Preparation of the soil means turning and tilling of the soil.
• Ploughing means loosen the soil again.
• The process of sowing the seeds of good quality is called as sowing.
• The process of putting humus in the field for a better crop is called as manuring.
• Watering the crop is known as irrigation. It is done in an interval of time.
• The cutting of crops when it becomes mature is called as harvesting.
• After harvesting the crop, it will sent to the sugar factory.

Down:

1. Irrigation
2. Storage 

(5) Crop  

Across:

1. Harvester
2. Gram

      6. Winnowing 

Column A                                          Column B

(i) Kharif crops                                  (e) Paddy and maize

(ii) Rabi crops                                   (d) Wheat, gram, pea

(iii) Chemical fertilisers                     (b) Urea and super phosphate

(iv) Organic manure                         (c) Animal excreta, cow dung, urine and plant waste

• Kharif crops are generally sown in rain season. For example: Paddy and maize.
• Crops grown in the winter season are called Rabi crops. For example: Wheat, gram, pea etc.
• To protect the crops from insecticides or pesticides, chemical fertilizers should be used like urea and super sulfate.
• Organic manure is made up of decomposition of biodegradable waste like animal excreta, cow dung, urine and plant waste.

(a) Kharif crop: The crops which are sown in the rainy season, called as kharif crops. This season is generally from June to September. For example: Paddy, maize, soyabean etc.

(b) Rabi crop: The crops which are sown in the winter season (October to March) are called Rabi crops. For example: Wheat, gram, pea, mustard etc.

1. Preparation of soil: The steps which are taken by a farmer before sowing are collectively known as preparation of soil. It involves tilling or ploughing, levelling and manuring. It bring the nutrients rich soil to the top so that plants can use these nutrients.
2. Sowing: The process of putting seeds in the prepared soil is called sowing. It is the most important and precious part of the crop production. Before sowing, the healthy and good quality of seeds are selected. The seeds should be sown at appropriate distances and depth. Seed drill is the best method of sowing seeds in the fields.
3. Weeding: The removal of unwanted plants that grow along with crop plants is called weeding. It is necessary since weeds complete with the crop plants for water, nutrients and light. Hence, they affect the growth of the plant or crop. Some weeds may be poisonous or harmful for animals and human beings.
4. Threshing: The process of separating the grain seeds from the chaff is called threshing. Threshing is carried out with the help of a machine called ‘combine’ which is infact a harvester as well as a thresher.

Irrigation: The process of watering the crops at different intervals is called irrigation. The time and frequency of irrigation varies from crop to crop, soil to soil and seasons to seasons. Two methods of irrigation that conserve the water are as follows:

1. Sprinkler system: This method is used in mainly uneven or irregular shape land where sufficient water is not available or shortage of water occurs. The perpendicular pipes that contains rotating nozzles on the top, are joined to the main pipeline at regular intervals. When water is allowed to flow through the main pipe under pressure with the help of a pump then it escapes from the rotating nozzles. It gets sprinkled on the crop as like it is raining. 
2. Drip irrigation: In this system, a network of narrow pipes or tubes is laid down in the field with small holes. When water flows through the narrow pipes, it falls drop by drop just near the roots of the plants. In this method, there is no wastage of water occurs as the water falls down drop by drop, therefore this system of irrigation is very useful in those regions where availability of water is poor. It is the best technique for watering the fruit plants, gardens and trees.

Wheat crops needs low temperature and less humidity for the growth. If they are sown in kharif season (rainy season), the seeds would get destroyed due to excess of water and would not grow. Hence, the yield of production would be low.

Soil is the source for the plants from which they derive their mineral nutrients that are essential for their growth. Continuous plantation of crops in a field affects the soil in the following ways:

1. The crop plant absorb nutrients from the soil continuously resulting in the soil deficient in important nutrients.
2. Due to the excessive use of fertilizers can make the soil either acidic or basic and the field becomes infertile.

Weeds are the undesirable plants or we can say unwanted plants that may grow naturally along with the crops. They are hazardous to the crops as they compete with the crops for the food, nutrients, water and sunlight. Hence, they must be controlled.

The process of controlling or removing the weeds (unwanted plants) from the field is known as weeding. There are several methods to remove weeds such as tilling in which weeds are uprooted. They are removed manually by cutting with the help of Khurpi. They are also controlled by chemicals known as weedicides which kills the weeds.