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

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. Our results show that land use, soil depth, and their interactions significantly influenced micronutrient concentrations. Micronutrients concentrations decreased with soil depth. They were significantly greater in woodland and fallow fields than in paddy and maize fields. They were positively correlated with the level of soil organic carbon, but negatively correlated with soil pH. Plant rotation and soil pH may contribute to enhance 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 fields.