Profile distribution of micronutrients in an aquic brown soil as affected by land use

Abstract

To assess the land use effects on soil micronutrients, this study examined the profile variation and storage of DTPA- extractable iron, manganese, copper and zinc at the depth of 0–150 cm of an aquic brown soil under four land use patterns, i.e. paddy, maize, and fallow fields and woodland, over 14 years in an ecological experimental station of northeastern China. Results showed that land use effect, soil depth, and their interactions on micronutrients were significantly different, and they were decreased with soil depth. Micronutrient storages in woodland and fallow field were significantly greater than in paddy field (<i>P</i> < 0.05), and significantly or comparatively greater than in maize field. Micronutrients were positively correlated with soil organic carbon, but negatively with soil pH in profiles. Plant cycling and soil pH may contribute a lot in enhancing soil micronutrient levels in woodland and fallow field, while the lower organic matter content and higher soil pH may inhibit the micronutrient availability in paddy field. The study suggested that the profile distribution of soil micronutrients was mainly controlled by biological cycling, anthropogenic disturbance and leaching and strongly affected by land uses.