Evaluation on fertilization of farmer practice based on grain yield of spring maize in Weibei dryland

Objectives The study investigated the maize yields and application rates of nitrogen (N), phosphorus (P) and potassium (K) fertilizers in farmer’s practices in Weibei dryland area, and made analysis and evaluation about the investigation results, to provide a guidance for scientific fertilizer application.

Methods From 2013 to 2016, questionnaire was conducted on fertilization rate and spring maize yield on 680 households from 5 counties, i.e. Chengcheng, Heyang, Hancheng, Huanglong, Pucheng, in the east of Weibei dryland.

Results 1) The average maize yield in the four-years in the studied area was 6000 kg/hm² and the portion of samples in very low (< 4200 kg/hm²), low (4200–5900 kg/hm²), moderate (5900–7600 kg/hm²), high (7600–9300 kg/hm²) and very high (> 9300 kg/hm²) yield level was accounted for 15.5%, 26.9%, 36.4, 14.4% and 6.5%, respectively, and 42.4% was below moderate level. 2) The four-year averaged N rate in spring maize was 249 kg/hm², and the portion of samples in very low, low, moderate, high and very high level was 4.5%, 11.6%, 33.9%, 35.3%, and 14.7%, respectively. The percentage of farmers with low N rate declined year by year from 6.9% in 2013 to 2.8% in 2016. However, the percentage of farmers with high N rate increased from 33.9% in 2013 to 37.1% in 2016. 3) The P rates in the research areas were at a relatively moderate level. The average P fertilizer rate in the four years ranged from 108 to 126 kg/hm² with the four-year average of 118 kg/hm². However, farmers applying higher rate of phosphorus (> 160 kg/hm²) still existed. 4) The average K rate in four years was 35 kg/hm² and 85.3% of the farmers applied K rate less than moderate (52–78 kg/hm²). 5) Yield response of spring maize to N and P fertilizers at low rates was high, but yield response to nitrogen fertilizer decreased obviously with the increase of N and P rates, and the yield would decrease at the high N and P rates. 6) No significant relationship existed between K rates and yields, although high grain yield was mainly from K rates at 40–80 kg/hm² and appropriate rate of K was beneficial to obtain higher grain yield.

Conclusions Generally, the maize grain yields in Weibei dryland areas are still in low levels. Overuse and underuse of N fertilizers are coexisted, and farmers with overuse of N are still increasing. P fertilizer application is generally reasonable, but inappropriate use of P is still existed. Although K application in the right rate helps to obtain higher grain yield and keep sustainable use of soil K, farmers pay little attention to K application.