54. What is a fertiliser Name ane te fertilisers State two harmful effects caused by the excessive use
What the
55. Explain how sol gets affected by the repead growing of crops in the same fields.
36. What is weeding? Why is weeding necessary?
47. What are weedicides? Name one weedicide What precaution should be taken while spraying weedicides? Why? 5. Give any four differences between manures and fertilisers
Answers
Answer:
1 Some examples of fertilizers are urea, potash, NPK (nitrogen, phosphorus, potassium), etc.
Harmful effects caused by the excessive use of fertilizers are-
(i) Excessive use of fertilizers makes the soil less fertile.
(ii) Excessive use of fertilizers causes water pollution.
2 Weeding can be defined as the removal of weeds (unwanted plants) from the field. Weeding is necessary because weeds compete with main crop plant for the different factors such as water, sunlight, nutrients and space and hence affect plant growth. Due to unwanted plants, there is reduction in yield also.
3.Weedicides are the chemicals which are sprayed over field to get rid of weeds. They will not show any effect on crop plants. Two popularly used weedicides are 2,4-D Ethyl ester, Neem extract, Glyphosate etc.
Explanation:
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