Sediment, runoff, nitrogen and phosphorus losses of sloping cropland of quaternary red soil in northern Jiangxi
In soil and water losses, 30％ is from sloping cropland in China.Nutrients losses with soil losses cause poor soil productivity, especially in red soils.This study aimed to investigate the sediment and runoff losses of sloping cropland of quaternary red soil and the N and P losses in the sediments and runoff.Site-specific long-term observations have been conducted during June-October 2011 in the plots of quaternary red soil in Soil and Water Conservation Eco-technology Garden of Jiangxi (E15°42′38″-l15°43′06″E, N29°16′37″-29°17′40″) located in De'an county, Jiujiang city, northern Jiangxi province.Four treatments such as bare land, downslope tillage, downslope tillage combined with hedgerow and transversal slope tillage were designed.Runoff, sediments and N and P contents were determined by collecting samples during every rainfall.The results showed that the surface runoff of bare land (15.96 mm) was highest, followed by downslope tillage (7.91mm) and downslope tillage+ hedgerow (6.64 mm) and transversal slope tillage (2.95 mm) was lowest.Compared with downslope tillage, runoff was reduced by 62.71％ by transversal slope tillage.Sediment yields of bare land (2205.5 t/km2) was highest, followed by downslope tillage (584.6 t/km2) and downslope tillage+ hedgerow (410.7 t/km2), and the sediment yields of transversal slope tillage (99.96 t/krn2) was lowest.Compared with downslope tillage, sediment yields of transversal slope tillage was reduced by 82.9％.The soluble N, ammonia nitrogen, nitrate nitrogen and soluble P losses in runoff were highest for bare land, and lowest for transversal slope tillage.They in the transversal slope tillage were reduced by 53.69％, 50.84％, 46.15％ and 57.47％, respectively than those in downslope tillage.The total N, total P, alkali-hydro N and available P losses in sediments were highest in the bare land but lowest in sediments of the transversal slope tillage.The organic N losses from the sloping cropland were dominated by the soluble N;while inorganic N losses were dominated by ammonia N.Moreover, the P losses in sediments accounted for most of total P losses.The study is helpful for better understanding of nutrient losses from the sloping cropland of quaternary red soil, and provide data support for protection and regulation of soil and water losses and non-point pollution from sloping cropland.
runoffsedimentserosionnorthern Jiangxiquaternary red soilsloping croplandnitrogen and phosphorus losses
国家科技期刊平台
NSTL
万方数据
维普
