基于较高土壤磷钾养分含量的玉米测土配方施肥研究

为了建立较高土壤磷钾养分含量下玉米施肥的技术指标,提高玉米产量和品质,减少玉米生产成本和环境污染,选择土壤磷钾养分含量较高的紫色土,按照"3414"回归最优设计方法实施玉米随机区组小区肥效试验,同时设置简易对比校正试验。结果表明,较高土壤磷钾养分含量下磷、钾肥当季利用率很低,NK或NP配施可以增强土壤对另一不施元素(磷或钾)的供给能力,但PK配施(不施氮)却削弱了土壤对氮的供给能力,而且玉米容易受高磷或高钾的胁迫,氮是玉米产量的限制因子;氮、磷、钾肥对玉米产量的影响符合报酬递减律,并能得到拟合度较高的一元二次和三元二次函数方程以及线性加平台。由此综合决策得出试验点的最高施肥量为N238.2kg/hm2,P2O567.5kg/hm2,K2O153.6kg/hm2;最高产量是8604kg/hm2;最佳施肥量为N224.6kg/hm2,P2O564.7kg/hm2,K2O135.8kg/hm2;最佳产量是8563kg/hm2;最佳N、P2O5、K2O比例为1:0.29:0.6。通过简易对比校正试验,找到农民不平衡施肥的原因,并做了分析预测。认定测土配方施肥必须根据不同的生态区和不同的农田生态系统建立不同的技术指标,才更具现实指导意义。

Soil Testing and Fertilizer Recommendation for Maize Based on Rather High Content of Soil Phosphorus and Potassium

In order to establish technical index of maize fertilization under rather high content of soil phosphorus and potassium,to increase yield and quality of maize,to reduce production costs and environmental pollution,field experiment with random block plots was carried out to study the effect of formulated fertilization on yield of maize according to the theory of ＂ 3414 ＂ regression optimum design under purplish soils with rather high content of soil phosphorus and potassium.The corrected experiment of simple contrast was also conducted at the same time.The results showed that,utilization ratios of phosphorus fertilizer and potassium fertilizer were very low under rather high content of soil phosphorus and potassium in the present season.Application of two nutrient elements of three elements（nitrogen,phosphorus and potassium） could increase another element（phosphorus or potassium） supplyment ability of soil.The nitrogen supplyment ability of soil reduced by application of both phosphorus and potassium（without nitrogen）,and maize could easily coerced by high content of soil phosphorus and potassium while nitrogen was limiting factor of maize yield.The effects of nitrogen,phosphorus and potassium fertilizer on maize yield conform to law of diminishing returns.Maximum application rate was N 238.2 kg/hm 2,P2O5 67.5 kg/hm 2,K2O 153.6 kg/hm 2 ;maximum yield was 8604 kg/hm 2 ;optimum rate of application was N 224.6 kg/hm 2,P2O5 64.7 kg/hm 2,K2O 135.8 kg/hm 2 ;optimum yield was 8563 kg/hm 2 ;optimum proportion of NPK 1：0.29：0.6 could get by highly simulated equation of one-factor and three factor models.Cause of unbalanced fertilization by farmers could be found by corrected experiment of simple contrast,and analytic forecast could be made.Fertilizer formula from the technical index established by different ecological region and different farmland ecosystem could possess practical significance.