QUALITY AND VALUE OF WIND-MOVABLE AGGREGATES IN CHERNOZEMIC Ap HORIZONS

Abstract

The 0–5 cm depth from Ap horizons of Orthic Brown, Dark Brown and Black Chernozemic soils when recently brought under cultivation, and of unfertilized Dark Brown Chernozemic soils under continuous wheat and a wheat-fallow rotation since 1912 were sampled in early May 1984. The samples were separated into 500- to 1000-μm, 250- to 500-μm, 100- to 250-μm, and < 100-μm-diameter water-stable aggregates by wet sieving. These four diameter classes of water-stable aggregates, considered to be the wind-erodible fraction of the soil, comprised 65–76% and 89–96% of the whole soil of the Ap horizons of recently and long-term cultivated soils, respectively. They were analyzed for organic matter, total N, available P, exchangeable K and monosaccharides. The source of the monosaccharides in the < 100-μm-diameter soil fraction, whether microbial or vegetative, was identified using ratios of hexoses to pentoses. The data allowed the calculation, using a number of assumptions, of the value of soil lost by wind erosion if its nutrients and organic matter had to be replaced by commercial fertilizers and cereal straw, respectively. The values obtained underscore the cost involved in poor land management, leading to wind erosion. Key words: Wind erosion, topsoil loss, organic matter (soil), monosaccharides, plant nutrients, land management