LONG-TERM TILLAGE EFFECTS ON SOIL QUALITY

Public interest in soil quality is increasing, but assessment is diffi cult because soil quality evaluations are often purpose- and site-spec ific. Our objective was to use a systems engineering methodology to ev aluate soil quality with data collected following a long-term tillage study on continuous corn (Zea mays L.). Aggregate characteristics, pen etration resistance, bulk density, volumetric water content, earthworm populations, respiration, microbial biomass, ergosterol concentration s, and several soil-test parameters (pH, P, K, Ca, Mg, Total-N, Total- C, NH4-N, and NO3-N) were measured on Orthic Luvisol soil samples coll ected from Rozetta and Palsgrove silt loam (fine-silty, mixed, mesic T ypic Hapludalfs) soils. Plots managed using no-till practices for 12 y ears before samples were collected for this study had surface soil agg regates that were more stable in water and had higher total carbon, mi crobial activity, ergosterol concentrations, and earthworm populations than either the chisel or plow treatments. Selected parameters were c ombined in the proposed soil quality index and gave ratings of 0.48, 0 .49, or 0.68 for plow, chisel, or no-till treatments, respectively. Th is indicated that long-term no-till management had improved soil quali ty. The prediction was supported by using a sprinkler infiltration stu dy to measure the amount of soil loss from plots that had been managed using no-till or moldboard plow tillage. We conclude that no-till pra ctices on these soils can improve soil quality and that the systems en gineering methodology may be useful for developing a more comprehensiv e soil quality index that includes factors such as pesticide and leach ing potentials.