川西北围栏草地氮、磷、钾肥效应研究

Effects of nitrogen,phosphate and potash fertilizers on fenced pasture in the northwestern Sichuan province

川西北草地由于超载放牧极其严重,草地质量退化迅速。为了维持草地的可持续发展,以围栏草地为研究对象,采用氮、磷、钾三因素不完全试验设计与裂区试验设计相结合的方法,探索防止草地退化的施肥技术。结果表明,速效氮、磷肥的施用能显著增加牧草产量。连续2年施用N90和P30比不施肥增产265.3%;第2年连续施肥比第2年不施肥相对增产40%-135%;第1年施肥处理的肥料后效比不施肥处理平均增产112.3%;干草产量随施氮量和施磷量的增加而增加,呈正直线相关;钾肥在该草地上没有表现出增产效果。氮肥能显著提高围栏草地品质,高氮处理（N135）比无氮处理（N0）粗蛋白含量增加20%以上。综合产量和品质两方面因素,川西北草地最佳施氮量为135~150 kg/hm^2,最佳施磷量为15-30 kg/hm^2,而钾肥可以不施;在最佳氮、磷肥配施下,可以采用隔年施肥来降低成本,增加经济效益。

As a result of the severe overgrazing, the quality of grassland had degraded obviously in the northwest Sichuan in recent years. In order to maintain sustainable development of this grassland from nutrients management in grassland point of view, a field trial with N, P and K three factors incomplete experimental design integrated with split experimental design was carried out to explore rational fertilization technologies to prevent grassland degradation. Results indicated that application of nitrogen and phosphate fertilizers significantly increased grass yield, about 265.3% of yield improvement measured for the N 90 kg/hm^2 and P2O5 30 kg/hm^2 treatment in two years compared to control and 112.3% of yield raised comparing to the residual effect of fertilization （only applying fertilizer in the first year）. A sequence of two-year fertilization increased 40%- 135 % comparing with single-year fertilization. Grass yield enhanced with adding of the amount of nitrogenous and phosphate fertilizers applied. Potash fertilizer didfft show positive effect on grass yield in this study. It was found that N significantly improved grass quality; more than 20% of crude protein was increased by N135 kg/hm^2 compared to the N treatment. Integrating yield and quality of grass, the optimum amount of nitrogenous and phosphate fertilizers were 135-- 150 kg/hm^2 N, 15-30 kg/hm^2 P2O5, respectively, and potash fertilizer was not necessary in the grassland of northwest Sichuan. Finally it was a feasible way to apply fertilizers only one time per two years in grassland for decreasing the cost.