EFFECT OF LONG-TERM MINIMUM TILLAGE PRACTICES ON SOME PHYSICAL PROPERTIES OF A CHERNOZEMIC CLAY LOAM

Abstract

This study was conducted to compare the long-term (20 yr) effects of conventional tillage, minimum tillage and no-till on various soil-water related properties within the tilled layer (0–30 and 30–60 mm) and immediately below the tilled layer (90–120 mm) under a spring cereal-summerfallow rotation cropping system. Parameters measured included saturated hydraulic conductivity, saturation percentage, plant-available water-holding capacity, large pore porosity, bulk density, and infiltration rate of the soil. Tillage treatment effects on these soil properties in each of the four sampling periods were not significantly different. The confidence interval test showed some temporal changes in these soil physical properties, of which hydraulic conductivity was the most affected. In the summerfallow field, regardless of the previous cereal crops, the steady infiltration rate was significantly lower in the soil under conventional tillage than with that under no-till. The results indicate that the surface soil structure was most stable under no-till. In the fresh stubble field, the type of cereal crop had an effect on the infiltration rate of the soil. The mean infiltration rate was higher in the summerfallow field than in the fresh stubble field and also was higher in the fresh barley stubble than in the fresh wheat stubble. Except for infiltration rates, there is no significant advantage of one tillage method over the other with respect to the soil physical properties measured in this Brown Chernozemic clay loam soil. Key words: No-till, minimum tillage, hydraulic conductivity, bulk density, infiltration