基于春玉米籽粒产量的渭北旱塬区农户施肥现状评价

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

【目的】调查渭北旱塬区农户玉米产量与氮、磷、钾肥的施用量,分析评价农户产量水平及基于产量的玉米施肥状况,为指导该区域的科学施肥提供参考。【方法】于2013—2016年在渭北旱塬区东部的澄城、合阳、韩城、黄龙、蒲城等5个县(市),实地入户调查680户农户玉米施肥量与产量。【结果】1)农户玉米产量4年平均值为6000 kg/hm^2,产量水平属于很低(<4200 kg/hm^2)、偏低(4200~5900 kg/hm^2)、中等(5900~7600kg/hm^2)、偏高(7600~9300 kg/hm^2)、很高(>9300 kg/hm^2)水平的农户数量分别占15.5%、26.9%、36.4%、14.4%、6.5%,低于中等水平农户占42.4%。2)农户春玉米施氮量4年平均值为249 kg/hm^2,其中施氮量属于很低(<76 kg/hm^2)、偏低(76~152 kg/hm^2)、适中(152~228 kg/hm^2)、偏高(228~304 kg/hm^2)和很高(>304kg/hm^2)的农户数量分别占4.5%、11.6%、33.9%、35.3%和14.7%,并且施氮量很低的农户数量呈现出逐年减少趋势,由2013年的6.9%减少到2016年的2.8%。但施氮量偏高的农户呈现出增加趋势,由2013年的33.9%增加到2016年的37.1%。3)农户春玉米施磷量处于一个较为适中的水平,4年平均磷肥施用量108~126 kg/hm^2,平均值为118 kg/hm^2,但施磷量很高(>160 kg/hm^2)的农户依然存在。4)农户春玉米施钾量4年平均值为35kg/hm^2,钾肥施用量低于适中量(52~78 kg/hm^2)的农户占85.3%。5)低施氮、磷肥时,增加氮、磷肥施用,有良好的增产效果,随着氮、磷肥施用量的升高氮肥的增产效果明显降低,但施氮、磷再增高时,产量会出现下降趋势。6)未发现施钾量与产量呈现出明显的关系,但高产量水平主要集中在钾肥施用量40~80 kg/hm^2,适量施钾有利于获得较高的籽粒产量。【结论】渭北旱塬区农户玉米籽粒产量总体上仍然处于偏低水平,在施肥上氮肥过量施用与不足并存,并且过量施氮农户呈现增加的趋势;磷肥施用总体上合理,但不合理施磷农户仍然占有一定的比例;该区农户不重视钾肥的施用,但适量施钾有助于获得较高的籽粒产量,且有助于土壤的可持续利用。

【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/hm^2 and the portion of samples in very low（ 〈4200 kg/hm^2）, low（4200–5900 kg/hm^2）, moderate（5900–7600 kg/hm^2）, high（7600–9300 kg/hm^2） and very high（ 〉9300 kg/hm^2） yield level was accounted for 15.5%, 26.9%, 36.4, 14.4% and6.5%, respectively, and 42.4% was below moderate level. 2） The four-year averaged N rate in spring maize was249 kg/hm^2, 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 from6.9% 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/hm^2 with the four-year average of 118 kg/hm^2. However, farmers applying higher rate of phosphorus（〉 160 kg/hm^2） still existed. 4） The average K rate in four years was 35 kg/hm^2 and 85.3% of the farmers applied K rate less than moderate（52–78 kg/hm^2）. 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/hm^2 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.