有机无机肥配施对设施菜地N_(2)O排放和NH_(3)挥发的影响

Effects of combined application of organic and chemical fertilizers on N_(2)O emission and NH_(3)volatilization in protected vegetable soils

我国设施菜地化肥施用量大,造成了大量的氧化亚氮(N_(2)O)和氨(NH_(3))损失。有机肥替代部分化肥是实现种养体系养分资源循环利用、减少化肥施用及其环境损失的有效措施。本研究以长沙近郊设施菜地为研究对象,利用小区试验种植奶白菜,试验共设不施肥处理(CK)、常规施肥处理(CON)、30%牛粪有机肥氮+70%化肥氮(CM)、30%鸡粪有机肥氮+70%化肥氮(NM)4个处理。采用静态箱法和密闭室间歇抽气法测定奶白菜生长季内的氧化亚氮排放和氨挥发,分析土壤N_(2)O排放和NH_(3)挥发动态,探讨等氮条件下有机无机肥配施对设施奶白菜的N_(2)O排放、NH_(3)挥发的减排效应及其影响因素。结果表明,与常规施肥相比,CM和NM处理的N_(2)O排放量分别减少了38.5%和33.1%,NH_(3)挥发的排放量分别减少了8.5%和19.4%,N_(2)O排放和NH_(3)挥发的总增温潜势分别降低了38.4%和33.0%。两种有机肥处理中,NM处理氨挥发显著低于CM处理,降幅达到11.9%。N_(2)O排放和NH_(3)挥发日通量与土壤温度分别呈极显著和显著正相关。常规施肥和NM处理的N_(2)O排放和NH_(3)挥发日通量与土壤铵态氮呈显著正相关,仅常规施肥处理的N_(2)O排放与土壤硝态氮呈极显著正相关。与常规施肥处理相比,CM和NM处理氮肥利用率分别提高26.8%和41.5%,且产量没有显著差异。因此,30%等氮有机肥+70%化肥在降低设施菜地N_(2)O排放和NH_(3)挥发的同时,还能保障设施蔬菜稳产,对减少蔬菜生产中的氮素损失具有重要意义。

The large amount of chemical fertilizer applied in protected vegetable soil in China has caused a lot of N_(2)O and NH_(3)losses.The substitution of organic fertilizer for part of chemical fertilizer is an effective measure to realize the recycling of nutrient resources in the planting and breeding system,and to reduce the application of chemical fertilizers and their environmental losses.In this study,a protected vegetable soil with Chinese cabbage planting in the suburbs of Changsha was taken as the research object.In the protected vegetable soil,a plot experiment was conducted to plant milk cabbage.The field experiment was conducted with four treatments:non-fertilization(CK),conventional fertilization(CON),30%N from cow manure organic fertilizer+70%from chemical fertilizer(CM),and 30%N from chicken manure organic fertilizer+70%from chemical fertilizer(NM).The emissions of nitrous oxide and ammonia volatilization during the growing season of Chinese cabbage were measured by static chamber method and closed chamber intermittent extraction method,respectively.The aims of the study were to explore the emission reduction effects of organic-inorganic fertilizer combined application on N_(2)O emissions and NH_(3)volatilization,and to clarify the influencing factors.The results showed that compared with conventional fertilization,N_(2)O emissions from CM and NM treatments decreased by 38.5%and 33.1%respectively,while NH_(3)volatilization from CM and NM decreased by 8.5%and 19.4%respectively.The total warming potential of nitrous oxide and ammonia volatilization in CM and NM treatments decreased by 38.4%and 33.0%,respectively.Among the two organic fertilizer treatments,the ammonia volatilization of NM treatment was significantly lower than that of CM treatment,with a decrease of 11.9%.N_(2)O emissions and ammonia volatilization daily fluxes was positively and significantly correlated with soil temperature.N_(2)O emissions and ammonia volatilization daily fluxes of CON and NM treatments was positively correlated with soil ammonium nitrogen,while N_(2)O emissions of CON treatment was positively correlated with soil nitrate nitrogen only.Compared with CON treatment,the nitrogen fertilizer utilization efficiency of CM and NM treatment increased by 26.8%and 41.5%,respectively,with no significant difference in yields.Therefore,combined application of organic fertilizer and chemical fertilizer can reduce N_(2)O and NH_(3)emissions as well as stabilize yields in the protected vegetable production systems,which is of great significance to reduce greenhouse gases emissions from vegetable production.