间歇淋洗干湿交替条件下氮肥的氮行为研究

采用土柱淋洗试验方法 ,对包膜尿素、尿素和硝酸铵在石碴土和粘壤质石灰性土壤中氮的行为进行了评价。结果表明 ,包膜尿素、尿素和硝酸铵的回收总氮量 (包括淋洗溶液中各种形态氮 ,土壤吸附的肥料氮和残余的肥料氮 )分别为施入总氮量的 90.5%、74.2 %、93.5%和91.5%、58.5%、91.1%。在 1750mL淋洗溶液中NO3--N分别占淋洗溶液中总氮量的 90%以上。在 7次淋洗干湿交替之后 ,土壤吸附的肥料氮 (NH4+-N和NO3--N)均不超过施氮总量的2.1% ;包膜尿素有62.7%和70.8%的氮以颗粒肥料存在于土壤中。 3种氮肥中包膜尿素较尿素和硝酸铵在土壤中释放持续的时间显著延长 ,尿素的氨挥发损失较高 ,硝酸铵淋失较快

The fate of nitrogen forms of nitrogen fertilizers under alternate leaching and drying conditions

A soil column leaching experiment was conducted in two textu reof calcareous soils to evaluate the fate of nitrogen froms of coated urea, ur ea and ammonium nitrate. The results showed that recovery of total N (included t otal N in the leacheate, fertilizer N adsorbed by soil and residual fertilizer N ) accounted for 90.5%, 74.2% and 93.5% of total N applied in gravel calcareou s s oil(the ratio of soil and gravel was 1:1.2) and 91.5%, 58.5% and 91.1% of to tal N applied in clay-loam calcareous soil with coated urea, urea and ammonium nitr a te, respectively; and cumulative NO3-N in 1750 mL of leacheate was more t h an 90% of total leacheate N. Soil N ( NH4＋-N and NO3--N) was not more than 2.1% of total N applied to the soils with different fertilizers after comp le tion of 7 times alternate leaching and drying. Nutrient released of coated urea was significantly longer than urea and ammonium nitrate, due to 62.7% and 70.8 % of coated urea nitrogen presented in the soils as granular fertilizers. Among t h ree kinds of chemical nitrogen fertilizer, the ammonia volatilization loss of u rea was possible higher and leaching loss of ammonium nitrate was faster in the soils.