Question

Complete the following table with reference to the soil.

Action	Effect	Result (w.r.t. fertility)
Construction of embankments
		Wind speed decreased
Farmland is kept fallow for some period
		Humus content increased.
Trenches are dug across a slope
Litter is burnt on the farm.
		Proves favorable for micro-organisms
		The salt content in the soil increases
Chemical fertilizers used excessively

Answer 1

Action	Effect	Result (w.r.t. fertility)
Construction of embankments	Reduction in the erosion of soil due to heavy rains.	Increase in Fertility
Planting trees	Wind speed decreased	Increase in Fertility
Farmland is kept fallow for some period	The fertility of soil gets maintained.	Increase in Fertility
Use of organic manures	Humus content increased.	Increase in Fertility
Trenches are dug across a slope	Check over the velocity of water running along the slopes and hence reduction in soil erosion	Increase in Fertility
Litter is burnt on the farm.	The proportion of ash in the soil gets increased.	Decrease in Fertility
Use of organic manures	Proves favorable for micro-organisms	Increase in Fertility
Excessive irrigation	The salt content in the soil increases	Decrease in Fertility
Chemical fertilizers used excessively	Decrease the number of microorganisms and so the proportion  of humus in the soil	Decrease in Fertility