Organic evolution through large discontinuous variations was propound by________?

Humus generally refers to the decomposed organic residues which have undergone a series of degradation and synthesis cycles. The humic substances consist of a series of highly acidic, yellow to black coloured, high molecular weight compounds ________, which can be separated using different extraction procedures:

The unique soil environment under the influence of plants roots is called rhizosphere and this term was given by________?

Any material such as straw, sawdust, leaves, plastic films, & loose soil that is spread upon the surface of the soil to protect the soil & plant roots from the effects of raindrops, soil crusting, freezing or evaporation:

In richer nations children are________% of the dependents?

The viral disease can be controlled by________?