太湖地区稻田氨挥发及影响因素的研究

应用微气象学方法研究太湖地区水稻三个不同施肥期施用尿素后的氨挥发损失 ,并对其影响因素 (气候、田面水中NH 4 N浓度和作物覆盖等 )的作用进行了分析研究。结果表明 ,水稻施用尿素后的氨挥发损失为各时期施氮量的 18 6 %～ 38 7% ,其中以分蘖肥时期损失最大 ,其次为基肥 ,穗肥氨挥发损失最小。氨挥发损失主要时期是在施肥后 7d内。在水稻不同生长期 ,各因素对氨挥发的影响能力大小并不一样 ,三个施肥期的氨挥发损失通量与施肥后田面水中铵态氮浓度呈显著正相关。

AMMONIA VOLATILATION FROM PADDY FIELDS IN THE TAIHU LAKE REGION AND ITS INFLUENCING FACTORS

Ammonia volatilization was assessed with a nondisturbing micrometeorological technique after urea application in three different periods in paddy fields (Gleyi stagnic Anthrosol) of the Taihu Lake region. And some factors (such as climate, NH₄⁺-N concentration in floodwater, et al.) influencing the ammonia loss were also studied. The results indicated that the ammonia volatilization loss from the applied urea in the paddy fields varied between 18.6% and 38.7% of the total N applied each time. The peak of ammonia loss occurred within the first week after the application, amounting to 80.7%~94.3% of the total ammonia loss in each period. The highest ammonia volatilization flux from the paddy fields occurred within the first 24~72 hours after the application of basal fertilizer, tillering fertilizer and ear bearing fertilizer, being N 7.49, 11.17, and 5.52 kg hm^-2d^-1, respectively in Treatment HN and N 3.01, 6.79, and 1.72 kg hm^-12 d^-1 in Treatment LN. The ammonia loss from the tillering fertilizer was the highest and from the earbearing fertilizer was the lowest. Factors influencing ammonia volatilization loss varied in effect in different rice growing stages. Significantly positive correlationship was observed between NH₃ loss and NH₄⁺-N concentration in the surface water in the paddy fields in all the three fertilization perio.