Effect of Tillage Systems on the Variability of Soil-Water Tensions and Soil-Water Content

ABSTRACT Field experiments were conducted on a Webster silty clay loam soil to study the effect of four different tillage systems (no-till, chisel plow, paraplow and moldboard plow) on soil-water tension and soil-water content. Data on soil-water tensions were collected by using tensiometers installed at 0.15, 0.3, 0.6, 0.9 and 1.5 m depths within the crop row. A portable pressure transducer equipped with a syringe needle and a digital pressure indicator was used to indicate soil-water tensions. Field data on soil-water tensions and volumetric soil-water contents for various tillage systems were collected during the 1983 and 1984 growing season. The results of this study indicated that tillage systems affected the soil-water tensions in the surface layer (0 to 0.3 m) of the soil in 1984, but the differences were not statistically significant at the 5% level in 1983. Results showed that the variability (standard deviation and range) of soil-water tensions increased when the soil became drier under all tillage systems, but the variability began to decrease at about 45 kPa of soil-water tension and continued to decrease further at higher values of soil-water tensions (reaching up to 80 kPa).