EFFECT OF TILLAGE ON THE SPATIAL VARIABILITY OF SOIL-WATER PROPERTIES

Soil samples, taken from the A and B horizons of no tillage and conven tional tillage treatment sites were analyzed for texture, organic carb on content, bulk density, effective porosity, and saturated hydraulic conductivity. The statistical parameters of mean, variance, coefficien t of variation, and coefficient of skewness, as well as scaling factor s, were determined for each of the variables. Autocorrelation structur es were also investigated. The lognormal distribution gave the best-fi t for the scaling factors. The spatial variability of physical and hyd raulic properties in each horizon was quite high. The variability of t he properties in the A horizon of the no tillage treatment was higher than that in the A horizon of the conventional tillage treatment. Diff erences in variability of the properties in the B horizon were not as large as in the A horizon, although all differences were considerable. Saturated hydraulic conductivity was the most spatially variable soil property and its variability was affected most by tillage. The spatia l variability of soil texture was not affected by tillage.