TILLAGE INFLUENCES AS MEASURED BY PONDED AND TENSION INFILTRATION

Increasing numbers of farmers are using conservation tillage systems f or reducing soil erosion. Tillage/residue management systems also infl uence soil properties at or near the surface through their effect on p ore arrangement surface sealing, and tillage pans. The purpose of this study wire to evaluate the near-surface pore characteristics of long- term tillage systems using ponded and tension infiltration measurement s. Three farmer-managed tillage systems were compared by measuring inf iltration on four or five soil map units (2 locations each) within a s ingle field in each system. Infiltration measurements also were made a t four other locations on researcher-managed tillage system plots arra nged in traditional randomized complete block designs. Differences bet ween farming systems were not significant because of inherent variabil ity because no surface seal developed on the soil, and because signifi cant tillage pans did not develop. Heavy rains did not occur during th e study year until the canopy was fully developed this prevented forma tion of surface seals even in tillage systems without much surface res idue. These measurements showed that hydraulic conductivity of long-te rm no-till and ridge-till systems was not reduced compared with conven tional tilled systems. All of the no-till and ridge-till systems exami ned had been cultivated for weed control in some years except for one farmer-managed system, which war disturbed by anhydrous ammonia applie d with a knife applicator. Negative effects of compaction in no-till m ay be offset by the positive influence of increased earthworm (Lumbric us and Apporecteda sps) activity.