Answer 1

Manures increase soil fertility by enriching the soil with organic matter and nutrients as it is prepared by the decomposition of animal excreta and plant wastes. On the other hand, fertilizers are mostly inorganic compounds whose excessive use is harmful to the symbiotic micro-organisms living in soil. Their excessive use also reduces soil fertility. Hence, fertilizers are considered good for only short term use.

Answer 2

Effects of using manures on soil quality:-

1. The manures enrich the soil with nutrients.
2. They provide a lot of organic matter (humus) to the soil and thus restores water retention capacity of sandy soils and drainage in clayey soil.
3. The addition of manures reduces soil erosion.
4. They provide food for soil organisms, like soil friendly bacteria.

Effects of using fertilizers on soil quality:-

1. By the continuous use of fertilizers, the soil becomes powdery, dry and rate of soil erosion increases.
2. By the use of fertilizers, the organic matter decreases which further decreases the porosity of soil and the plant roots do not get oxygen properly,
3. The nature of soil changes to acidic or basic.