[Effect of soil tillage on phosphorus loss from slope land: an experimental study]

Intensive soil erosion and nutrient loss from slope land not only resulted in the serious degradation of soil quality, but also threatened the water environment of the lower area. In this paper, a simulated rainfall experiment with loessial soil was conducted to study the characteristics of the loss of different phosphorus forms under the conditions of tillage and compaction (no-tillage). The results showed that in comparing with compaction, tillage increased the loss of dissolved P(DP), sediment extractable P(SEP) and sediment total P(STP) by 10 times due to the increase of runoff and sediment amount. The forms of the lost P were mainly sediment-combined P, and the ratios of DP/BAP and BAP/TP in the lost runoff were 12% and 2.6% under compaction, and 15% and 2.4% under tillage, respectively. The application of no-tillage or mulch-keeping fallow in Summer was effective to decrease soil and nutrient loss from slope land, which would be effective and significant both to soil degradation prevention and water environment protection in the lower area of Loess Plateau.