Potential of integrated agronomic practices to increase grain yield and utilization efficiency of fertilizers in summer maize production

Objectives Integrated and concord agronomic practices are the foundation of the high grain yield and fertilizer efficiencies in summer maize production in Shandong Province. The current integrated management was modified and testified in this paper, for achieving the highest potentials of yield and efficiency in maize production.

Methods The testify experiment was conducted in State Key Laboratory of Crop Biology and College of Agronomy, located in Dawenkou County of Tai'an City, from 2013 to 2017. A summer maize hybrid of ‘Zhengdan958’ was used as the experimental material. The experiment was composed of four treatments: local conventional practice CK (no tillage, straw returning); Opt-1(relative to CK, delay maize harvesting, increase planting density, decrease N application rate, and split apply fertilizers); HY (the maximum grain yield with highest fertilizer rate and three application practices); Opt-2 (decrease planting density and fertilizer rate). The grain yield, dry matter weight and utilization efficiency of N, P and K of summer maize were measured.

Results The grain yield of Opt-2 treatment was 27.6%–37.9% and 19.2%–31.9% higher than those of CK and Opt-1 treatment, but significantly lower than those of HY treatment; its average dry matter translocation efficiency was 5.8% higher than that of CK, but lower than those of Opt-1 and HY treatment; the contribution of dry matter accumulated before tasseling stage was significantly lower than Opt-1 and HY as well, but the average dry matter accumulation after tasseling was 28.7%–36.8% higher than CK and Opt-1, which was similar with HY treatment. The grain N accumulation in Opt-2 treatment was 146.0–171.4 kg/hm², which was lower than that in HY treatment but higher than in CK and Opt-1 treatment. The grain P accumulation in Opt-2 treatment was 75.6–92.7 kg/hm², which was higher than all the other treatments. The grain K accumulation in Opt-2 was 40.0–43.8 kg/hm², which was 38.3%–58.9% and 16.3%–32.6% higher than those in CK and Opt-1 treatment, respectively. The utilization efficiencies of N and P in Opt-2 treatment were highest but that of K was the lowest.

Conclusions Under the same sowing and harvest date with conventional optimum practices in maize, the modified optimum practices increase plant density by 10% and nitrogen fertilizer rate by 15%, and conduct twice top dressing. As a result, the dry matter accumulation of the whole growing period is significantly increased, especially that after tasseling, and the high yield is increased by 27.6%–37.9%, and the partial fertilizer productivities of N and P increased by 47.5%–67.6%.