Drivers in Soil Ecosystem Function: Enzyme Activities and Carbon, Nitrogen, Phosphorus, and Sulfur Contents.

Understanding interactions and dynamics among different nutrient pools and enzyme activities that govern their cycling processes under different management practices could assist the evaluation and development of management strategies that sustain and enhance ecosystems functions. The objective of this study was to use multivariate analysis to reveal the interrelationships of carbon (C), nitrogen (N), phosphorous (P), sulfur (S) pools and11 key enzyme activities involved in their transformations. Nutrient pools evaluated include total, soluble, and microbial forms. Five micronutrients were also tested. Forty-five soils from five long-term (> 30 yrs) management practices were evaluated. Treatments included undisturbed, set-aside from cultivation, moderately grazed, heavily grazed, and winter wheat (Triticum aestivum L.). Of micronutrients tested, B and Mg were most limiting in these systems. Of macronutrients evaluated, C_org, C_mic, N_t, and N_mic were more limiting in the cultivated than in the uncultivated soils. There is some indication that mineralization of organic S is a key process that governs ecosystem functions. The capacity of soil enzymes to release simple sugar and inorganic nutrients appeared to be a key factor regulating nutrient cycling.