Mammals have thermoregulatory abilities and mobility to avoid unfavorable features of current weather. In contrast, plants are rooted in place and must accept that rates of metabolic processes are determined by ambient conditions they cannot avoid. Crop ecology gives special emphasis to environment as the main determinant of what will grow, how rapidly, and for how long.

Crop communities extend a strong influence over their local microenvironment. Nearly all cropping practices are directed towards, or have the effect of, modifying chemical or physical aspects of that environment. The next two chapters deal specifically with these issues, beginning in Chapter 6 with the aerial environment, giving emphasis to solar energy as the driving force for productivity, and continuing in Chapter 7 with properties of soils.