CBSE Class 8 Science Advanced Biology Crop Production and Management Long Answer Questions Set 01

Long Answer Type

Question 1. How do farmers protect their crops from pests and weeds?
Answer:
Weed control:
1. Mechanical: pulling the weeds out by hand, ploughing, and using a trowel (khurpa).
2. Cultural: proper bed preparation, timely sowing, intercropping and crop rotation.
3. Chemical: spraying weedicides such as 2,4-D, atrazine, fluchloralin and isoproturon.
4. Biological: using insects or organisms that destroy the weed, such as cochineal insects for prickly pear; grass carp fish for aquatic weeds.
Protection from pests and diseases:
5. Treating seeds and soil to control seed-borne and soil-borne diseases, and spraying fungicide for air-borne diseases.
6. Growing mixed crops, intercropping and crop rotation, which reduce pests; using biopesticides such as neem leaves in storage; fumigating stored grain.
In simple words: Farmers remove weeds by hand, cultural, chemical and biological means and keep pests off by treating seeds, spraying and rotating crops.

Teacher's Note:
1. Group the methods as weed control and pest control.
2. Organise the answer under weeds and pests.

Question 2. Define harvesting. Name the implements used.
Answer:
Harvesting is the cutting of the crop after it has matured.
It is done by hand with a sickle or by a machine called a harvester.
A combine is a machine that both harvests and threshes the crop.
After harvesting, the grain is separated from the chaff by threshing, and small farmers separate them by winnowing by hand or with a winnowing machine.
In simple words: Harvesting is cutting the ripe crop, using a sickle, harvester or combine.

Teacher's Note:
1. Mention threshing and winnowing as the following steps.
2. The harvest is celebrated by festivals like Pongal and Baisakhi.

Question 3. If there is low rainfall in a village throughout the year, what measures will you suggest to the farmers for better cropping?
Answer:
1. Choose crops and cropping systems that need little water, such as bajra, jowar, gram and pulses.
2. Use water-saving modern irrigation such as drip and sprinkler systems, with fertigation.
3. Give only the optimum quantity of water at the right time and keep a time schedule for irrigation.
4. Keep weeds under control, since they take water.
5. Use manure to improve the water holding capacity of the soil, and use wells and tube wells to tap ground water.
6. Practise mixed cropping or crop rotation so that the crop is not lost entirely.
In simple words: Grow low-water crops, irrigate with drip or sprinkler and use manure to hold water.

Teacher's Note:
1. Use the water-saving measures from the irrigation topic.
2. Point-wise answers score well.