Effect of tillage on the spatial variability of soil water properties

Soil samples, taken from the A and B horizons of no tillage and conventional tillage treatment sites were analyzed for texture, organic carbon content, bulk density, effective porosity, and saturated hydraulic conductivity. The statistical parameters of mean, variance, coefficient of variation, and coefficient of skewness, as well as scaling factors, were determined for each of the variables. Autocorrelation structures were also investigated. The lognormal distribution gave the best-fit for the scaling factors. The spatial variability of physical and hydraulic properties in each horizon was quite high. The variability of the properties in the A horizon of the no tillage treatment was higher than that in the A horizon of the conventional tillage treatment. Differences 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 spatial variability of soil texture was not affected by tillage.