肥料氮素在土娄土中的淋溶

Leaching of Nitrogen Fertilizer in “Lou” Soil Columns

采用室内土柱恒温条件下模拟研究粪肥或／和尿素混施入土娄土耕层后在多次灌溉下对铵态氮、硝态氮和水溶性有机态氮的淋溶深度和数量的影响。结果表明：三种施肥处理淋出液中氮素形态均以硝态氮为主，且淋溶到９０ｃｍ土层以下，有机、无机肥混施后减少了无机肥中硝态氮的淋溶率；无机肥和有机、无机肥混施处理以铵态氮次之，其量与土层深度呈对数式衰减，显著淋溶到３０ｃｍ土层；而有机肥处理以有机态氮次之，显著淋溶到３０ｃｍ土层，５０ｃｍ以下含量甚微。硝态氮和水溶性有机氮随灌溉水向下迁移，对底土具有培肥作用。

Effect of manure and/or urea applied to topsoil on leaching amounts and depth of ammonia, nitrate and water soluble organic nitrogen using soil columns was studied. The results were shown that: the main nitrogen form of leacheate was all nitrate-N and which leached to the bottom of 90 cm soil horizon when applied three fertilizer treatments, and leaching loss ratio of nitrate-N was lower mixedly applied manure and urea than only applied urea; the second nitrogen form of leacheate in applied urea and mixedly applied manure and urea was ammonia-N and which amounts was indexically decreased with soil horizon depth increased, and significantly leach to the bottom of 30 cm; the second nitrogen form of leacheate in applied manure was organic nitrogen and which significantly leach to the bottom of 30 cm but could hardly leach to the bottom of 50 cm. Nitrate and water soluble organic nitrogen were migrated with deionised water migrating and increased subsoil fertility.