Question

Why moist and warm conditions favours decomposition?

Answer 1

The amount of water in the soil, both indirectly and directly, affects the decomposition rate of organic matter. Indirectly, a wet soil results in a slower break down because water fills the air spaces in the soil, depriving the microbes of oxygen. But all living organisms also require water, so a soil that is too dry directly decreases organic matter decomposition, as the microorganisms found in soil cannot survive without water. Soils that undergo period wet and dry periods -- like a garden that you water weekly -- instead of remaining constantly wet or dry, will cause organic matter to decompose more quickly.




At temperatures of 40 degrees Fahrenheit and above, soil bacteria experience some activity. But once temperatures reach 70 F, soil microbes really get going, up to about 100 F. Microbial populations double in the soil with every additional 10 F. Because of this, soil organic matter breaks down faster in the summer, and areas with year-round warm weather will decompose more organic matter annually than areas that experience cold winters.