Nutrient Losses from Sloping Lands as Affected by Surface Mulching and Cultivation in Sichuan
IPNI-2009-CHN-SC17
15 Feb 2010
2009 Annual Interpretive Summary
Nutrient Losses from Sloping Lands as Affected by Methods of Surface Mulching and Cultivation in Sichuan, 2009
The objective of this project was to evaluate effects of different methods of surface mulching and cultivation on corn yield and nutrient losses from Sichuan’s sloping farmlands during the summer rainy season. Three types of surface mulching included a check (no mulching), wheat straw, and plastic film. The three methods of cultivation included non-ridged or flat cultivation, down-slope cultivation (ridged), and contour cultivation (ridged). The NPK fertilizer rate was 225-150-150 kg N-P2O5-K2O/ha according to soil test fertilizer recommendations.
Contour cultivation was best at enhancing corn yield, followed by flat cultivation. Plastic mulching was better than straw mulching, but all mulching treatments produced significantly higher corn yields compared to the check. The combination of plastic mulching + contour cultivation produced the highest corn yield. Any methods able to conserve more soil moisture could produce more corn yield on these rain-fed sloping lands. Treatments without mulching led to much more severe water losses and soil erosion compared to those with mulching. In this case, the down-slope treatment performed the worst, followed by the flat cultivation treatment. The amounts of soil eroded from the down-slope treatment (25.4 t/ha) and flat cultivation treatment (22.3 t/ha) were about 5 to 6 times that observed from the contour treatment (4.3 t/ha). Straw mulching reduced soil losses to only 0.1 t/ha under contour cultivation and 0.9 t/ha under down-slope cultivation. Though plastic mulching was superior to straw mulching in terms of corn yield response, it increased soil erosion by more than 10 times to 2.2 t/ha under contour cultivation and 10.8 t/ha under down-slope cultivation. Since the nutrient losses from these sloping lands were induced by water loss and soil erosion, the quantity of N, P, and K losses was closely related to these factors.
Contour cultivation + plastic mulching was very effective at increasing corn yields on these rain-fed sloping lands; however, contour cultivation + straw mulching was superior in terms of both corn yield response and preventing the loss of nutrients. Sichuan-BFDP 09