黄河三角洲盐碱土冬小麦氮磷肥料效应模型研究

通过大田试验,研究了黄河三角洲盐碱土地区冬小麦合适的肥料效应模型。在冬小麦生长季设置4种不同的氮磷肥用量,根据"3414"试验设计8种不同的肥效试验处理,以探讨线性加平台、一元二次、平方根和二元二次4种不同模型的拟合效果。结果显示,4种肥料效应模型的拟合结果经检验都达到极显著水平(P0.01)。在一元肥料效应模型中,氮磷一元二次模型拟合效果最好,最高收益分别为7 448.3元·hm~(-2)和7 357.7元·hm~(-2),最佳经济氮磷用量分别为254.4 kg·hm~(-2)和98.6 kg·hm~(-2)。对比一元与二元模型,后者拟合效果较好,最佳经济氮磷用量分别为244.1 kg·hm~(-2)和94.2 kg·hm~(-2),即氮磷肥配比为2.6∶1,经济效益为7 432.4元·hm~(-2),氮肥农学利用率为6.2 kg(籽粒)·kg~(-1)(N),磷肥农学利用率为13.8 kg(籽粒)·kg~(-1)(P_2O_5)。结合拟合度、最佳经济施肥量、经济收益、肥料农学利用率和一元模型的局限性分析得出,二元二次肥料效应模型最优,可作为黄河三角洲地区盐碱土冬小麦氮磷肥效模型的最佳选择。

Comparison of fertilizer-effect models on winter wheat response to nitrogen and phosphorus fertilizers in saline soils in the Yellow River Delta

Salt-affected soils distribute widely across the Yellow River Delta, which inhibit plant growth and crop yield in this area. Although fertilizer application can alleviate the adverse impact of salinization on crop, little remains known about the per-formance of different fertilizer-effect models on simulation of '3414' fertilizer experiments in winter wheat field in saline soils. Among the essential elements, nitrogen (N) and phosphorus (P) are usually the most important nutrients limiting plant growth in saline or non-saline soils. In this study, four fertilizer-effect models were used to simulate the impact of N and P fertilizers on wheat yield in a field experiment in Lijin County of Shandong Province. The study aimed at selecting suitable fertilizer-effect model for wheat grown in saline soils in the Yellow River Delta. Four levels of N and P fertilizers (N: 0 kg·hm-2, 135 kg·hm-2, 170 kg·hm-2, 405 kg·hm-2; P: 0 kg·hm-2, 53 kg·hm-2, 105 kg·hm-2, 157.5 kg·hm-2) were set in eight treatments based on the '3414' test in order to investigate the fit effect of the four fertilizer-effect models — linear plus plateau, unary quadratic, square root and binary quadratic. To ensure the accuracy of fertilizer-effect models, the least square method was used in the statistical regression analysis. The results suggested that the four fertilizer-effect models had an extremely significant level (P < 0.01) based on the fit test. Unary quadratic model of effects of N and P fertilizers was the best among unary fertilizer-effect models, which suggested that the highest income levels were 7448.3 ￥·hm-2and 7357.7 ￥·hm-2 and the recommended N and P rates were 254.4 kg·hm-2and 98.6 kg·hm-2, respectively. Compared with the unary models, binary model was better. In binary model, the best N and P application amounts were respectively 244.1 kg·hm-2 and 94.2 kg·hm-2, with N to P ratio of 2.6. In the model, the economic benefit and agronomic efficiency of N and P were 7432.4 ￥·hm-2, 6.2 kg(grain)·kg-1(N) and 13.8 kg(grain)·kg-1(P2O5), respectively. On the basis of the fitted curve, the binary quadratic model had the better economic fertilizer rate, agronomic efficiency, economic benefits than the unary models. Then the binary quadratic fertilization model was the best for wheat cul-tivation in saline soils in Yellow River Delta.