Water-stable aggregates and associated organic matter in forest, savanna, and cropland soils of a seasonally dry tropical region, India

摘要

The study was undertaken to quantify the distribution of soil in different size fractions of water-stable aggregates, and organic C, total N, and total P associated with these aggregates, along a gradient of forest-savanna-cropland in the Indian dry tropics. The effect of residue (wheat straw) amendment under dryland cultivation was also investigated. Proportions of macroaggregates (>0.3 mm) were highest in the forest and lowest in the cropland soil and ranged from 58–66 in forest, to 55 in savanna and 25–36 in cropland. In contrast, microaggregates (0.05) in the short term, although the proportion of macroaggregates increased, indicating an improvement in soil structure. Thus soil degradation after conversion of natural systems to cropland can be arrested up to some extent by residu