苏丹草-黑麦草轮作制中氮、磷、钾肥施用效果研究

【目的】为苏丹草-黑麦草轮作制中合理利用养分、水分及培肥土壤提供理论依据。【方法】连续3年盆栽试验研究苏丹草(Sorghum sudanense)-黑麦草(Lolium L.)轮作制中氮、磷、钾肥对饲草产量、养分吸收、水分利用及土壤养分的影响。【结果】氮、磷、钾肥配施显著增加饲草产量,2005/2006、2006/2007、2007/2008年度的饲草总量分别为1690.0、2091.3、1770.7g/pot。与CK处理(NPK配施)相比,不施氮处理(PK)的饲草产量分别减少700.7%、1256.9%、856.3%,不施磷处理(NK)分别减少426.3%、384.9%、792.3%,不施钾处理(NP)分别减少15.9%、4.4%、10.6%。氮、磷、钾肥配施促进饲草的养分吸收,3个年度NPK处理的总吸氮(N)量分别为6.36、4.91、6.85g/pot,总吸磷(P)量分别为0.79、1.01、0.82g/pot,总吸钾(K)量分别为11.58、6.36、5.62g/pot,养分利用效率显著高于其它处理。3个年度NPK处理水分生产率分别为16.5、16.1、16.2kg·m-3,明显高于其它处理。轮作体系下,土壤有机质,NP、NK、NPK处理的全氮,NP、PK、NPK处理的速效磷,NK、PK处理的缓效钾、速效钾均上升;土壤pH,NP、NPK处理的缓效钾、速效钾下降,而PK处理的全氮、NK处理的速效磷基本稳定。【结论】苏丹草-黑麦草轮作体系下,合理配施氮、磷、钾肥能持续获得高产、促进饲草养分吸收和有效改善土壤肥力。

Effect of N, P, K Application on Yield, Nutrient and Water Utilization Under Sudangrass and Ryegrass Rotation Regime

Objective] Sudangrass and ryegrass rotation is a new type of cropping system in Jianghan Plain, which developed very fast in recent years. So it is essential to understand the optimum nutrient and water management measures in this new system.Method] Effect of NPK fertilizer on yield of forage grass, nutrition and water utilization under sudangrass and ryegrass rotation was studied through continuous pot experiments for three years. Result] The results showed that NPK combination could obviously improve the yield of forage grass, and the total yield in the period of 2005-2006, 2006-2007, 2007-2008 was 1 690.0 g/pot, 2 091.3 g/pot, 1 770.7 g/pot, and yield in PK treatment (No N) was 700.7%, 1 256.9%, 856.3% lower than that of NPK treatment, and yield in NK treatment (No P) was 426.3%, 384.9%, 792.3% lower than that of NPK treatment, and yield for NP treatment were 15.9%, 4.4%, 10.6% lower than that of NPK treatment, respectively. NPK combination could improve nutrition uptake, and total N uptake in the period of 2005-2006, 2006-2007, 2007-2008 were 6.36 g/pot, 4.91 g/pot, 6.85 g/pot, and was 10.0 times, 14.8 times, 10.6 times higher than that of PK treatment, and was 3.7 times, 1.8 times, 5.1 times higher than that of NK treatment, respectively, but was similar to NP treatment. Total P uptake were 0.79 g/pot, 1.01 g/pot, 0.82 g/pot, and was 4.6 times, 6.8 times, 5.3 times higher than that of PK treatment, and was 2.4 times, 2.3 times, 2.9 times higher than that of NK treatment, respectively, but was similar to NP treatment. Total K uptake were 11.58 g/pot, 6.36 g/pot, 5.62 g/pot, and was 5.2 times, 8.4 times, 4.9 times higher than that of PK treatment, and 3.9 times, 2.3 times, 3.9 times higher than that of NK treatment, and were 80.9%, 57.4%, 200.5% higher than that of NP treatment, respectively. Water productivity in three years was 16.5 kg·m~(-3), 16.1 kg·m~(-3), 16.2 kg.m-3, and was 3.8 times, 5.4 times, 4.2 times higher than that of PK treatment, and was 2.3 times, 1.3 times, 2.6 times higher than that of NK treatment, and was 16.4%, 8.8%, 22.4% higher than that of NP treatment, respectively. In this rotation, soil pH degraded, but soil organic matter all upgraded. Soil total N in NP, NK, NPK treatments upgraded, but soil total N in PK was steady. Soil extractable P in NP, PK and NPK treatments upgraded obviously, and soil extractable P in NK increased slightly. Soil available K in NK and PK treatments upgraded obviously, but available K in NP and NPK degraded. Conclusion] NPK combination increased yield of forage, improved nutrient uptake and soil fertility in sudangrass and ryegrass rotation system.