EFFECTIVENESS OF MANURE AND COMMERCIAL FERTILIZER IN RESTORING PRODUCTIVITY OF AN ARTIFICIALLY ERODED DARK BROWN CHERNOZEMIC SOIL UNDER DRYLAND CONDITIONS

Abstract

A field was artificially eroded by levelling in 1957. Continuous cropping to barley for 7 yr followed by a wheat-fallow rotation for 14 yr without nutrient application did not significantly improve the soil productivity of severely "eroded" land. Subsequently, a wheat-fallow experiment was conducted from 1980 to 1985 to determine the effects of 30 Mg ha−1 feedlot manure or 150 kg commercial fertilizer N (as urea) + 150 kg commercial fertilizer P (as triple superphosphate) ha−1 on restoring the productivity to soil from which 10–20 cm or 46+ cm of soil had been removed. The manure and commercial fertilizer treatments essentially restored productivity within the first year, as measured by wheat yields, regardless of severity of erosion. During years of drought stress which often occur under dryland conditions, the manure application on the "eroded" soil treatments resulted in yields greater than those on check or fertilized plots. The manure significantly increased the organic matter, total N, NO3-N, available P, and water-stable aggregate status of the soil. There was a decrease in the difference in carbohydrates between undisturbed and 'eroded' plots from 1982 to 1984. Key words: Soil erosion, manure, commercial fertilizer, topsoil loss, soil organic matter, productivity