田面水位对稻田氨挥发影响的试验研究

稻田在施氮肥后有明显的氨挥发损失,田面水位对稻田氮素流失具有关键作用,为探究田面水位对稻田氨挥发的影响,基于室内土柱试验装置,采用密闭室通气法,对水稻各肥期不同田面水位下的氨挥发进行了研究。结果表明,田面水位会显著影响稻田氨挥发,在整个施肥期间,相同施肥量条件下,当田面水位为1、3、5 cm时,氨挥发累积量占总施氮量的比例分别为23%、15%、12%,施入基肥和分蘖肥后1 cm处理下氨挥发通量的峰值最高,3 cm处理次之,5 cm处理最低,施入穗肥后表现为5 cm处理高于1 cm处理和3 cm处理。田面水位在施入基肥和分蘖肥后,高水位低NH_4~+-N浓度和低水层温度是氨挥发降低的主要因素,施入穗肥后,低水位高硝化强度是抑制氨挥发的重要因素。为降低氨挥发,建议水稻在施用基肥和分蘖肥时采用较高水位,施用穗肥时适当降低水位。

Effect of water level on ammonia volatilization in paddy filed

Significant nitrogen loss by ammonia volatilization occurs after applying nitrogen fertilizer in paddy fields,and water level plays a key role in nitrogen loss.To investigate the effect of water level on ammonia volatilization in paddy fields,this paper presents a research on ammonia volatilization under various water levels during different fertilization stages of paddy fields,using continuous air-flow enclosure method and laboratory column experiments.The results indicated that water level had significant effects on ammonia volatilization in paddy fields.During the fertilization period,when the same amount of fertilizer was applied,the proportion of ammonia volatilization in total nitrogen application was 23%,15%,and 12%,under the water level of 1,3,and 5 cm,respectively.After applying base fertilizer and tiller fertilizer,the ammonia volatilization flux reached the peak value when the water level was 1 cm,then decreased when the water level was 3 cm and hit the lowest value with water level of 5 cm.However,after the application of panicle fertilizer,the highest ammonia volatilization flux value was under the water level of 5 cm.Low NH₄⁺-N concentration and low water temperature caused by high water level were the main factors for ammonia volatilization reduction after base fertilizer and tiller fertilizer were applied,and the high nitrification intensity in low water level was an important element associated with the inhibition of ammonia volatilization after the application of panicle fertilizer.It is recommended that adopt a higher water level during the application of base fertilizer and tiller fertilizer,and lower the water level when applying panicle fertilizer to reduce ammonia volatilization.