Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN 55108, USA.
J Environ Qual. 2010 Feb 19;39(2):492-9. doi: 10.2134/jeq2009.0265. Print 2010 Mar-Apr.
Increasing groundwater nitrate concentrations in potato (Solanum tuberosum L.) production regions have prompted the need to identify alternative nitrogen management practices. A new type of polymer-coated urea (PCU) called Environmentally Smart Nitrogen (Agrium, Inc., Calgary, AB) is significantly lower in cost than comparable PCUs, but its potential to reduce nitrate leaching and improve fertilizer recovery has not been extensively studied in potato. In 2006 and 2007, four rates of PCU applied at emergence were compared with equivalent rates of soluble N split-applied at emergence and post-hilling. Additional treatments included a 0 N control, two PCU timing treatments (applied at preplant or planting), and a soluble N fertigation simulation. Nitrate leaching, fertilizer N recovery, N use efficiency (NUE), and residual soil inorganic N were measured. Both 2006 and 2007 were low leaching years. Nitrate leaching with PCU (21.3 kg NO(3)-N ha(-1) averaged over N rates) was significantly lower than with split-applied soluble N (26.9 kg NO(3)-N ha(-1)). The soluble N fertigation treatment resulted in similar leaching as PCU at equivalent N rates. Apparent fertilizer N recovery with PCU (65% averaged over four rates) tended to be higher than split-applied soluble N (55%) at equivalent rates (p = 0.059). Residual soil N and NUE were not significantly affected by N source. Under the conditions of this study, PCU significantly reduced leaching and tended to improved N recovery over soluble N applied in two applications and resulted in similar N recovery and nitrate leaching as soluble N applied in six applications.
在马铃薯（Solanum tuberosum L.）种植区，地下水中硝酸盐浓度的增加促使人们需要寻找替代的氮肥管理措施。一种新型的聚合物包膜尿素（PCU），称为环境智能氮（Agrium，Inc.，卡尔加里，AB），其成本明显低于同类 PCU，但在马铃薯中，其减少硝酸盐淋失和提高肥料回收率的潜力尚未得到广泛研究。在 2006 年和 2007 年，在出苗时比较了 4 种不同用量的 PCU 与等量的可溶性 N 在出苗和培土后分施的效果。其他处理包括 0 N 对照、2 种 PCU 施用量处理（在种植前或种植时施用）和可溶性 N 滴灌模拟。测量了硝酸盐淋失、肥料 N 回收率、N 利用效率（NUE）和残留土壤无机 N。2006 年和 2007 年均为低淋失年份。PCU（N 用量平均为 21.3 kg NO3-N ha-1）的硝酸盐淋失显著低于可溶性 N 分施（26.9 kg NO3-N ha-1）。可溶性 N 滴灌处理在等效 N 用量下的淋失与 PCU 相似。PCU 的表观肥料 N 回收率（4 个用量平均为 65%）在等效用量下趋于高于可溶性 N 分施（55%）（p = 0.059）。残留土壤 N 和 NUE 不受 N 源的显著影响。在本研究条件下，PCU 显著降低了淋失，与可溶性 N 分 2 次施用相比，N 回收率趋于提高，与可溶性 N 分 6 次施用的 N 回收率和硝酸盐淋失相似。
