不同深施方式对太湖地区稻田氨挥发和氮肥利用率的影响

Effects of Different Deep Fertilization Methods on Ammonia Volatilization and Nitrogen Use Efficiency in Rice Fields in Taihu Lake Region

本研究以太湖地区稻田为研究对象开展连续两年的田间试验,通过设置不施氮肥(CK)、常规施氮(CN)、减氮表施(RN)、减氮侧深施(RNS)和减氮穴施(RNP)5种施氮处理,探究不同深施方式对稻田氨挥发与氮肥利用率的影响。结果表明,与表施处理(CN和RN)相比,RNS和RNP通过降低田面水NH4+-N浓度和pH分别减少30.95%~41.54%和66.71%~72.23%的氨挥发排放(P<0.05)。相较于RN处理,RNP促进水稻根系生长并增加根区土壤有效氮含量,进而增加水稻产量(6.23%),提高氮肥利用率(50.15%),降低土壤氮盈余(63.92%)(P<0.05)。与CN处理相比,RNS显著降低土壤氮盈余(29.20%)(P<0.05),但水稻吸氮量和氮肥利用率均未显著增加。相较于RNS,RNP进一步降低氨挥发损失(50.84%)和土壤氮盈余(51.07%),提高氮肥利用率(40.40%)(P<0.05)。综上所述,RNP的农学和环境效益最高,但因穴施机械及肥料造粒技术等因素的限制,尚难应用于实际生产;而侧深施肥在我国水稻大规模集约化生产中效益较高且切实可行。

A two-year field experiment was conducted in the Taihu Lake Region with five treatments:no nitrogen(N)input(CK),conventional N broadcasting(CN),reduced N broadcasting(RN),reduced N with side deep fertilization(RNS),and reduced N with point deep fertilization(RNP),to explore the effects of different deep fertilization methods on ammonia volatilization(NH3)and N use efficiency(NUE)in paddy fields.The results showed that compared to surface application treatments(CN and RN),RNS and RNP reduced ammonia volatilization by 30.95%–41.54%and 66.71%–72.23%(P<0.05),respectively,owing to the reduced NH4+-N concentration and pH in floodwater.RNP significantly promoted the root growth of rice,and increased soil available N content in root zone than RN,thereby increasing rice yield(6.23%)and NUE(50.15%),and decreasing soil N surplus(63.92%)(P<0.05).RNS markedly reduced soil N surplus(29.20%)(P<0.05),but N uptake and NUE of rice were not significantly increased versus CN.In contrast with RNS,RNP further decreased NH3 volatilization(50.84%)and soil N surplus(51.07%),and increased NUE(40.40%)(P<0.05).Overall,RNP can achieve the maximum agronomic and environmental benefits,but it is difficult to be widely used in agriculture production owing to the limitation of the development of point-deep fertilization machines and fertilizer granulation technology,whereas side-deep fertilization method is feasible to be adopted in large-scale intensive production of rice due to the higher agronomic and environmental benefits.