Question

Why is organic manure considered better than fertilizers?
A. It cannot be prepared in fields
B. It is less rich in plant nutrients
C. It improves fertility and texture of the soil
D. It decreases the water holding capacity of the soil

Answer 1

Hint: Organic manure involves biodegradable wastes that does not harm or decreases the quality of soil but increases aeration and water holding capacity of the soil. Chemical fertilizers can harm the soil and natural environment.

Complete answer:
An organic manure is a biodegradable waste made from animal excreta and agriculture wastes. It represents partially decayed wastes that are added to the soil. It increases the fertility, aeration and water holding capacity of the soil. Because of their biodegradable property, organic manure does not harm the environment and thus, it is better than chemical fertilizers. Chemical fertilizers are made in chemical factories and are more nutrient specific. The use of the chemical fertilizers to increase agricultural productivity due to rising demands by the ever-increasing population has contributed significantly to pollution. We have now realized that there are problems associated with the overuse of chemical fertilizers and there is an increasing demand to switch to organic farming to use biofertilizers.

The various biofertilizers are:
a) Free-living nitrogen-fixing bacteria: Azotobacter, Azospirillum help to enrich the nitrogen content of the soil.
b) Symbiotic nitrogen-fixing bacteria: The most important is Rhizobium present in the root nodules of leguminous plants.
c) Mycorrhiza: It is a mutually beneficial or symbiotic association of the fungus with the root of a higher plant. Example- many membranes of genus Glomus form mycorrhiza. The fungal symbiont in these associations absorbs phosphorus from soil and passes it to the plant.

Hence, the correct answer is option C.

Note: Organic farming involves the growth of crop and livestock without using any synthetic chemicals. It reduces pollution, increases soil fertility, reduces soil erosion, etc. It is an environmental-friendly technique.