Abstract:

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/hm2, P2O5 67.5 kg/hm2, K2O 153.6 kg/hm2; maximum yield was 8604 kg/hm2; optimum rate of application was N 224.6 kg/hm2, P2O5 64.7 kg/hm2, K2O 135.8 kg/hm2; optimum yield was 8563 kg/hm2; 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.