长期施肥条件下小麦农田氨挥发损失的原位研究

In situ study of ammonia volatilization from wheat cropland under long-term continuous fertilization

采用密闭通气法在长期定位试验基础上研究了连作小麦的原位氨挥发损失。结果表明,小麦昼夜都有氨挥发损失,全天的氨挥发速率在小麦孕穗期为14.69±4.86 g/(hm2.d),灌浆期为18.84±4.09 g/(hm2.d),成熟期为20.91±3.28 g/(hm2.d);昼间的氨挥发损失随小麦生育期的推移迅速增大。单施N、P的氨挥发速率进入灌浆期后开始大幅度增加,单施M的氨挥发速率进入成熟期才大幅度增加。肥料配施可以明显增加小麦孕穗期昼间氨挥发损失速率,不同程度地降低了小麦灌浆期和成熟期昼间氨挥发速率。作物夜间的氨挥发损失小于白天相同处理的氨挥发损失,占白天氨挥发损失平均速率的比例也因生育期而异,孕穗期57.34%±15.93%、灌浆期37.78%±17.84%、成熟期13.73%±11.19%。小麦生育期氨挥发损失与土壤养分含量有一定的相关关系,灌浆期降水对氨挥发的影响也因施用肥料的不同而异。

Enclosure growth chamber was used to collect and determine in situ ammonia volatilized from continuous wheat cultivation cropland based on a long-term fix position experiment. The obtained result showed that ammonia volatilized both in daytime and nighttime from cropland. The daily ammonia volatilization rate was 14.69 ±4.86 g/（ha· d） in booting, 18.84 ± 4.09 g/（ha·d） in filling, and 20.91 ± 3.28 g/（ha·d） in ripening,respectively. The ammonia volatilization. rate in daytime rapidly went up along with the lapse of growing stage of wheat. In the condition of single application N or P, ammonia volatilization rate increased sharply from filling stage, while that of M did not occure until ripening stage. Compared to M, N and P, formula fertilization could increase the ammonia volatilization rate in booting obviously; but in some degree it decreased volatilization rate in filling and ripening in daytime. The rate of ammonia volatilization in nighttime was lower than that in daytime with the growing of wheat, which is 57.34% ±15.93 % in booting, 37.78 % ± 17.84% in filling, and 13.73% ± 11.19% in ripening, respectively. Ammonia volatilization correlated with soil nutrient content to some extent. Effects of precipitation in filling on ammonia volatilization were different due to various fertilizers applied.