(a) Role of soil organisms in the formation of soils are.-
(i) The microbes by their enzymes, break down rock particles.
(ii) Burrowing activities of microbes enhance aeration and introduction of water into the rocks, thereby enhancing rock break down. ( Earthworm activities).
(iii) and other rodents cause pressure by their burrowing activities, thereby creating channels and tracks through which air and water penetrate to promote the breakdown of rocks.
(iv) Activities of earthworm, ants, termites and crickets disintegrate rocks through engulfing, crushing, and expulsion of smaller soil particles.
(v) Soil micro -organism incorporate organic matter into the soil due to their burrowing activities, thus enhancing the faster disintegration of rocks.
(vi) The wastes of organic acidic and hasten the disintegration of rocks.
(vii) Fungi and soil - borne algae act on soil organic matter which releases acids that promote rock disintegration.
(viii) Lower plant forms, such as lichens and mosses can disintegrate rock by their activity through the release of corrossive substances from their fast holds.
(ix) As plant roots without organisms into the soil, they encounter and breakdown rocks as they force their way through rocks.
(x) Dead organism accumulate and aid soil formation
(b) Ways in which soil organisms improve soil for growth of crops are:
(i) Improve soil structure and granulation.
(ii) Improve soil aeraton.
(iii) Improve soil water percolation or drainage.
(iv) Increase organic matter content of soil.
(v) Increase soil colloidal properties
(vi) Enhance the cation exchange capacity of the soil.
(vii) Through burrowing, they eave holes for crop root to penetrate.
(viii) Increase the mineral or nutrient status of the soil
(ix) Stabilize soil pH through the increase of soil organic matter