不同氮肥缓释化处理对夏玉米田间氨挥发和氮素利用的影响

摘要

[Objectives]Slow-release processing technologies have been used in urea production to reduce ammonia volatilization and de-nitrification of nitrate in soil, so to improve crop N uptake and eventually improve nitrogen utilization. Here the ammonia volatilization characteristics of different control-released urea were compared to provide references for their practical application.[Methods]Ain-situ field experiment was conducted in a sandy soil in two years in North China plain. The treatments included no nitrogen fertilization control (CK), calcium nitrate (CN), common urea (CU), polymer-coated urea (CRF), release-controlled urea (LCU), polymer gel urea (CLP) and urea formaldehyde (UF). The ammonia volatilization loss, maize yield and nitrogen utilization were determined during the summer maize growing seasons.[Results]1) The ammonia volatilization mainly occurred in the first week after applied into soil, the cumulative ammonia volatilization accounted for 81.6% of the whole growing period for CU, and 62.2%–82.2% for CLP, LCU, CRF and UF. 2) In 2014, the cumulative ammonia volatilization in CU was N 14.9 kg/hm2; those were significantly decreased by 21.7%–64.6% from CLP, LCU, CRF and UF. In 2015, that of the CU was N 17.3 kg/hm2, the decreases were by 17.3%–57.2%. 3) The ammonia volatilization loss ratios of the CU, CRF and LCU were higher than 60.0% in the two monitoring years, and that of CU reached to 76.0% in average, while the ratio of the UF was 37.6%. 4) The yearly average yields of the UF, CLP, LCU and CRF were increased significantly by 6.3%–18.8%, compared with the CU. 5)The nitrogen use efficiency with UF was up to 57.9%, and those with CLP, LCU, CRF, CN and CU were 42.4%, 38.3%, 38.3%, 23.5% and 20.8%, respectively.[Conclusions]The urea formaldehyde, polymer gel urea, lost-controlled urea and polymer-coated urea can significantly reduce the ammonia volatilization loss, improve the maize yield and nitrogen use efficiency. Among the tested control-released nitrogen fertilizers, urea formaldehyde and polymer gel urea perform better for the high-yield, high-efficiency and less N loss.%【目的】氨挥发是农田氮素损失的重要途径之一，氮肥类型或尿素氮肥缓释处理方式直接或间接影响作物吸收及土壤理化性质，进而影响氨挥发和氮素利用效率。通过不同缓释处理技术减低氨挥发和氮素降解释放速率来提高作物氮素吸收，对于提高作物氮素利用率具有重要意义。【方法】通过两年田间原位监测试验，以不施氮肥为对照(CK)，设硝酸钙(CN)、常规尿素(CU)、树脂包膜尿素(CRF)、控失尿素(LCU)、凝胶尿素(CLP)、脲甲醛(UF)7个处理，研究不同氮肥缓释化处理对夏玉米土壤氨挥发损失量、玉米产量和氮素利用的影响。【结果】1)氨挥发主要集中于施肥后一周以内，常规尿素氨挥发累积量占整个生育期氨挥发累计总量平均为81.6%，凝胶尿素、控失尿素、树脂包膜尿素、脲甲醛氨挥发累积量占整个生育期氨挥发累计总量的比例介于62.2%～82.2%之间。2)2014年夏玉米田间氨挥发监测期内，常规尿素的氨挥发累计总量为 N 14.9 kg/hm2，凝胶尿素、控失尿素、树脂包膜尿素、脲甲醛处理与常规尿素相比下降幅度介于21.7%～64.6%。2015年，常规尿素的氨挥发累计总量为 N 17.3 kg/hm2，凝胶尿素、控失尿素、树脂包膜尿素、脲甲醛处理与常规尿素相比下降幅度介于17.3%～57.2%。3)化肥氮在常规尿素、树脂包膜尿素以及控失尿素处理中的贡献率较高，两年均达60%以上，其中常规尿素中化肥氮的贡献率平均高达76.0%。而化肥氮在脲甲醛中的贡献率较低，平均仅为37.6%。4)与常规尿素相比，脲甲醛、凝胶尿素、控失尿素以及树脂包膜尿素的产量也有显著增加，两年平均产量增幅为6.3%～18.8%。5)不同氮肥的夏玉米氮肥利用率也有显著差异，其中脲甲醛为最高，平均高达57.9%，其次为凝胶尿素、控失尿素、树脂包膜尿素、硝酸钙和常规尿素，分别为42.4%、38.3%、38.3%、23.5%和20.8%。【结论】氮肥中的氨挥发主要集中于施肥后一周以内。与常规尿素相比，脲甲醛、控失尿素、树脂包膜尿素、凝胶尿素均能明显减少氨挥发损失、提高产量和氮肥利用率，以脲甲醛和凝胶尿素效果更显著，是高产、高效、低损失的肥料类型。