Which factors improve soil fertility? select the three correct answers.

A:nitrogen

B:horizons

C:manure

D:humus

E:bedrock

A) Nitrogen

C) Manure

D) Humus

Explanation:

Soil fertility leads to the capability of a soil to support agricultural plant growth, i. e. to produce plant environment and occur in continued and steady yields of high quality. A fertile soil will include all the important nutrients for basic plant nourishment, as well as other nutrients required in smaller amounts.