OBJECTIVE FORESTRY

Detailed explanation-1: -Earthworms and other animals tunnel through and mix the soil. They aerate the soil and allow water to penetrate more deeply. Humans also influence soil formation.

Detailed explanation-2: -Biotic agents have greatly affected the soil formation process. These include organisms that live in the soil, such as bacteria and gophers, and vegetation growing on the surface.

Detailed explanation-3: -Soil formation is influenced by organisms (such as plants), micro-organisms (such as bacteria or fungi), burrowing insects, animals and humans. As soil forms, plants begin to grow in it. The plants mature, die and new ones take their place. Their leaves and roots are added to the soil.

Detailed explanation-4: -Plants, animals and micro-organisms (fungi and bacteria) all affect soil formation by producing or contributing to humus production. The amount of humus in a soil is a result of how much plant material has been incorporated into it. If vegetation is sparse a soil will be low in humus and less fertile.

Detailed explanation-5: -By far, the most numerous microbes in soil are bacteria, which have just one cell. Also abundant are fungi, which produce long, slender strings of cells called filaments, or hyphae. The actinomycetes are in-between these two organisms. They are advanced bacteria that can form branches like fungi.