State 4 ways by which through which a soil is depleted

Explanation:

Leaching – Plant nutrients are lost beyond the reach of plant roots. Usually caused by excessive rainfall washing nutrients deep down into sub-soil beyond new roots reach.

Soil erosion – Top soil is lost by the agent of erosion e.g. wind, water.

Monocropping – This utilizes only specific nutrients from a particular zone making it exhausted. -It also causes accumulation of certain pests and diseases.

Continuous cropping –This continuously exhaust the fertility of land unless the the land if fallowed.

Change of soil PH -Use of either acidic or basic fertilizers affect soil pH and Consequently the presence of micro-organisms hence soil fertility affected.

Burning of vegetations –Destroys organic matter and soil structure. Nutrients are lost and soil exposed to erosion.

Accumulation of salts – Common in waterlogged areas and semi-arid areas in which poor drainage causes evaporation during the dry periods, making the soil saline.

they deliver oxygen to the blood

compost can be added to topsoil as a:

pesticide