生活污水尾水灌溉对秸秆还田稻田氨挥发的影响

通过土柱模拟实验,研究了生活污水尾水灌溉对秸秆还田稻田田面水氮素转化、氨挥发排放以及水稻产量的影响。结果表明:生活污水尾水灌溉显著提高了稻田田面水NO_3~--N浓度和田面水pH,并显著提高了产量、植株吸氮量和土壤脲酶活性。与清水灌溉处理相比,不施氮肥时生活污水尾水灌溉可使秸秆还田稻田氨挥发累积排放量显著降低35%;正常施氮时生活污水尾水灌溉增加了秸秆还田稻田氨挥发排放总量,但由于显著增加了水稻产量,因此单位产量氨挥发排放量有所降低。由此可见,秸秆还田稻田利用生活污水尾水灌溉,不仅可消纳净化生活污水、替代部分氮肥,还可增加水稻产量、降低单位产量稻田氨挥发排放。

Effects of treated domestic sewage irrigation on ammonia volatilization in straw-returning paddy fields

In this study, a soil column monitoring experiment was conducted to assess the effects of treated domestic sewage irrigation on floodwater ammonium(NH₄⁺-N)and nitrate nitrogen(NO₃^--N)concentrations, ammonia volatilization(NH₃), and paddy yields in straw-returning paddy fields. Treated domestic sewage significantly improved the NO₃^--N concentration and the pH of floodwater, and also significantly improved the rice yields, plants nitrogen uptake, and soil urease activity. Compared with tap water irrigation, treated domestic sewage irrigation significantly decreased the cumulative NH₃ emission by 35% without nitrogen fertilizer application; while it increased the cumulative NH₃ emission when nitrogen fertilizer was applied with the same N input. The yield-scale NH₃ volatilization losses were decreased with the use of treated domestic sewage irrigation due to the improved yield. Thus, treated domestic sewage irrigation in straw-returning paddy fields can not only reuse and purify wastewater, partially replace nitrogen fertilizer use, increase paddy yields, but also reduce the yield-scale NH₃ volatilization losses, which is promising for rice production and environmental emission.