【摘要】 <正> 利用¹⁵N技术在灌溉条件下研究施氮水下（75,150,225kg/hm²）对冬小麦产量、氮素利用和土壤残留态无机态氮及其有效性的影响。结果表明:75kg/hm²和150kg/hm²施氮处理的冬小麦获得最高产量,二者没有显著性差异;而225kg/hm²处理的冬小麦因过量施氮造成籽粒产量下降,并低于不施氮处理。植株对氮素的利用率随施氮水平的增加而下降,分别为38.5％,32.3％和22.4％。作物收获后发现,225kg/hm²处理中所施氮的46％仍更多还原

【Abstract】 The experiment was conducted with 15N tracing techniques in Shijiazhuang from 1994 to 1995.Three nitrogen rates, including optimum rate (150 kg/hm2) based on the recommendation of local farmers, above 50% of optimum rate (225 kg/hm2) and below 50% of optimum rate (75 kg/hm2) , were selected to study the effect of application rates of ammonium bicarbonate on yield of winter wheat and fate of applied nitrogen under local management and irrigated condition. The results showed that nitrogen uptake and grain yield of wheat under fertilized treatments were higher than those in unfertilized treatment (except 225 kg/hm2 treatment). The highest yield and top dry matler weight (grain 6.80 t/hm2, top 14. 70 t/hm2) were obtained in optimum N applied treatment (150 kg/hm2), while the highest nitrogen recovery efficiency (38-5%) of ammonium bicarbonate by winter wheat was found in below 50% of optimum rate treatment (75 kg/hm2) due to the relatively high basic fertility of the field. However, nitrogen recovery efficiency of ammonium bicarbonate decreased with the increasing N application rate. The highest residue of fertilizer N was found in 225 kg/hm2 treatment, and 46% of the residue existed in the top layer of the soil (0~50 cm). The unaccounted N from fertilizer were 30. 20% , 36. 56% , 31. 25% in 75 kg/hm2, 150 kg/hm2, 225 kg/hm2 treatments respectively according to 15N balance calculation in soil-plant system. The effect of residue N in soil on the next crop, maize, in 225 kg/hm2 treatment was best in three fertilized treatments, suggesting the possibilities of nitrate leaching down in 225 kg/hm2 treatment.更多还原