In some cases crop rotation has a greater impact on microarthropods than insecticide use. Management plans for transitional production systems generally include legume crops or green manures in a crop rotation as a way to maintain soil fertility. Legumes as an organic matter and nitrogen source support larger numbers and greater activity of soil microbes compared to inorganic nitrogen sources. The application of animal manures and composts as nutrient sources generally increases the abundance and activity of soil plant and animal life. Microbial and protozoan activity is highest in organically fertilized soils.
Manure causes increases of microbial predators, while decreasing the abundance of plant parasites.
Collembolas, earthworms, and some predatory mites increase in abundance when manure is added to crop soils, and manure may help to control nematode populations. Because of the complexity and interactions of soil processes, it is important they be examined in concert in studies of farms and fields making the transition. Chandler strawberries were winter-planted in a replicated randomized block design. Experimental treatments include conventionally-farmed strawberry plots with normal inputs, and plots farmed organically and planted to strawberries during the first year of conversion and thereafter. In the experiments, changes in the soil during transition to organic management practices have been due in large part to the removal of chemical stress, especially the removal of fumigation as a preplanting soil treatment.