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The antecedent soil moisture status of a catchment is an important factor in hydrological modelling[ Traditional Hortonian in_ltration models assume that the initial moisture content is constant across the whole catchment\ despite the fact that even in small catchments antecedent soil moisture exhibits tremendous spatial hetero! geneity[ Spatial patterns of soil water distribution across three transects "two in a burnt area and one in an unburnt area# in a semi!arid area were studied[ At the transect scale\ when the factors a}ecting soil moisture were limited to topographical position or local topography\ spatial patterns showed time stability\ but when other factors\ such as vegetation\ were taken into account\ the spatial patterns became time unstable[ At the point scale\ and in the same areas\ topographical position was the main factor controlling time stability[ Scale dependence of time stability was studied and local topography and vegetation presence were observed to play an important role for the correlation between consecutive measures depending on the scale[

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Organic refuse application to soil may improve soil structure and thus soil quality and productivity. Two semiarid, structureless soils with <10 g kg−1 organic C (OC), differing in clay mineralogy, were amended annually at rates of 30 g kg−1 fresh or composted refuse to a total of 60 g kg−1 in a greenhouse experiment lasting 2 yr. Fresh refuse additions significantly increased the soil aggregate stability in water by 17%. Composted refuse application only increased aggregate stability in the beidellitic clay‐dominated soil (13%). In both soils, the greatest increase in OC and humin following refuse additions occurred in the fine silt fraction, which contained less decomposed organic matter than the clay fraction. In the beidellitic clay soil, this increase in OC was larger than in the illitic clay soil. The aggregate stability of the beidellitic clay soil was significantly correlated with OC and humin of fine silt fraction.