紫色土地区水钾耦合对油菜产量及水分利用效率的影响研究

为探讨川中丘陵紫色土地区不同决策目标下油菜适宜的水钾用量，通过水钾耦合模型的建立与分析，研究了不同钾素水平和水分处理对油菜产量及水分利用效率的影响。结果表明:在本试验条件下开花期土壤水分对产量影响最大，蕾苔期次之；油菜总产量增长速率随水钾用量的增加呈现先增后减趋势；水钾耦合对产量和水分利用效率均有促进的正效应，效应大小顺序为:水钾耦合 > 土壤含水量 > 施钾量。籽粒产量最高值出现在蕾苔期开花期高钾高水处理，此时水分利用效率（WUE）为14.6 kg/（hm²·mm），而水分利用效率最高值出现在蕾苔、开花期。高钾和土壤水分分别控制在0.66 g/kg，θ_f58.7%组合，但是籽粒产量降低约19.7%。在季节性干旱和酸性紫色土区油菜推荐的水钾模式为:蕾苔、开花期土壤水分分别控制在θ_f68%，θ_f80%，施钾量控制在0.57 g/kg，此时籽粒产量和水分利用效率均较高且经济效益达到最大。

Effect of Coupling of Water and Potassium on Rape Yield and Water Use Efficiency in Purple Soil Areas

To seek for the appropriate amount of water and potassium under different decision objectives on rape in purple soil areas of Sichuan Basin, a model were established to examine the effect of different soil water contents(θ_f40%, 60%, 80%) on the yield and WUE of rape under different rates of potassium fertilizer(0, 0.33, 0.66 g/kg). Results showed that soil water contents at flowering stage had the greatest impact on yield, followed by vegetativing stage; the increase rate of production with increasing amount of water and potassium showed the decrease after increasing trend; both soil moisture and fertilizer have pronounced effects on the rape yield and WUE, the effect order of interaction was potassium and water coupling > soil moisture > potassium. Amounts for highest yield were 0.66 g/kg of potassium and θ_f80% of soil moisture at all stages, WUE was 14.6 kg/(hm²·mm). However, amounts of potassium and soil moisture for highest WUE were 0.66 g/kg, θ_f58.7%, respectively, at vegetativing stage, θ_f74.7% at flowering stage, but the yield lowered by roughly 19.7%. In consideration of the comprehensive performance of the yield, WUE and economic efficiency, the recommended coupling pattern of water and potassium in areas of seasonal drought and acidic purple soil was set as that potassium application rate was 0.57g/kg and soil moisture was θ_f68% at vegetativing stage, soil moisture was θ_f80% at flowering stage.