硝化抑制剂/菌剂对设施土壤–蔬菜体系中氮素去向的影响

Effects of nitrification inhibitor/microbial inoculum on nitrogen fate in soil-vegetable system of greenhouse

【目的】明确硝化抑制剂与菌剂单施与配施条件下设施土壤–茄子生产体系中氮的去向,为设施茄子科学施氮提供理论依据。【方法】田间试验采用随机区组设计,设置6个处理:不施氮肥对照(CK)、常规施氮720 kg/hm^(2)(FN)、减施30%氮肥(N 504 kg/hm^(2),RN),减氮30%配施硝化抑制剂(RND)、菌剂(RNB)和同时配施硝化抑制剂与菌剂(RNDB)。研究设施土壤–茄子体系中茄子对氮素的吸收利用、土壤剖面NO_(3)^(–)-N累积量、N_(2)O排放和NH_(3)挥发的气态损失量及各去向所占比例。【结果】1)RNDB处理产量为112.27 t/hm^(2),比RND处理显著增加11.0%;可溶性糖含量达0.95%,较RND和RNB处理分别显著提高17.3%和18.8%。2)各处理吸氮量均为果实>茎秆>叶片>根系;RNDB处理的总吸氮量为259.66 kg/hm^(2),比RN处理显著提高16.1%;氮肥表观利用率最高为20.87%,与RND和RNB处理差异不显著;氮肥农学效率为99.69 kg/kg,显著高于RND处理。3)相同施氮量下,RNDB处理的气态净损失量(N_(2)O与NH_(3))和净损失率分别为16.05 kg/hm^(2)和4.73%,RNDB的N_(2)O累积排放量比RNB显著降低28.8%,各处理间NH_(3)挥发累积量差异较小。4)0—60 cm土层土壤剖面NO_(3)^(–)-N累积量为FN>RNB>RN>RND>RNDB>CK,除CK处理外,RNDB处理的累积量最低为873.1 kg/hm^(2),RNDB处理土壤硝态氮累积量比RN、RNB和RND处理分别减少17.6%、17.7%和2.2%;60—120 cm土层土壤剖面NO_(3)^(–)-N累积量为FN>RN>RNB>RND>RNDB>CK,RNDB处理的累积量为744.0 kg/hm^(2),比RND和RNB处理分别降低1.0%和25.2%。【结论】相比RN处理,减氮30%同时配施硝化抑制剂与菌剂能有效减少N_(2)O气态损失,对NH_(3)挥发影响较小,提高茄子氮素吸收量,显著降低0—60 cm土层土壤氮素残留,是实现茄子优质高产、环境友好的有效措施。

【Objectives】We assessed the fate of soil nitrogen under single application and combined application of nitrification inhibitors and microbial inoculum in a greenhouse eggplant production system.【Methods】The experimental field was set up with a randomized block design and 6 treatments,including no nitrogen fertilizer(CK),conventional nitrogen application of 720 kg/hm^(2)(FN),30%reduction of nitrogen fertilizer(N 504 kg/hm^(2),RN),30%reduction of nitrogen combined with nitrification inhibitor(RND),microbial inoculum(RNB)and simultaneous application of nitrification inhibitor and microbial inoculum(RNDB).The nitrogen uptake and utilization,NO_(3)^(-)-N accumulation in soil profile,N_(2)O emission,gaseous loss of NH_(3) volatilization and the proportion of each destination in the soil greenhouse eggplant system were assessed.【Results】1)The yield of RNDB treatment was 112.27 t/hm^(2),which was 11.0%higher than that of RND treatment.The soluble sugar content of RNDB was 0.95%,which was significantly higher than that of RND and RNB by 17.3%and 18.8%respectively.2)The order of nitrogen uptake in all the treatments was:fruit>stem>leaf>root.The total nitrogen uptake of RNDB treatment was 259.66 kg/hm^(2),which was 16.1%higher than that of RN.The apparent nitrogen use efficiency of RNDB treatment was the highest(20.87%),which was not significantly different from RND and RNB treatment.The agronomic efficiency of nitrogen fertilizer was 99.69 kg/kg,which was only significantly higher than that of RND treatment.3)Under the same nitrogen application rate,the net gaseous loss(N_(2)O and NH_(3))and net loss rate in RNDB treatment were 16.05 kg/hm^(2) and 4.73%respectively.The accumulative N_(2)O emission of RNDB was significantly lower than that of RNB by 28.8%.There was no significant difference in NH_(3) volatilization accumulation among treatments.4)The accumulation of NO_(3)^(-)-N in 0-60 cm soil profile was FN>RNB>RN>RND>RNDB>CK.Except in CK treatment,the lowest accumulation of RNDB treatment was 873.1 kg/hm^(2).The accumulation of soil NO_(3)^(-)-N in RNDB treatment was 17.6%,17.7%and 2.2%lower than that in RN,RNB and RNDB treatment,respectively.The accumulation of NO_(3)^(-)-N in 60-120 cm soil profile was FN>RN>RNB>RND>RNDB>CK.The NO_(3)^(-)-N accumulative amount of RNDB treatment was 744.0 kg/hm^(2),which was 1.0%and 25.2%lower than that of RND and RNB treatment,respectively.【Conclusions】Reducing nitrogen by 30%combined with nitrification inhibitor and microbial inoculum application could effectively reduce N_(2)O and NH_(3) gaseous loss,improve nitrogen absorption of eggplant and significantly reduce nitrogen residue in 0-60 cm soil profile.It is an effective measure to realize environment-friendly production of high quality and high yield eggplant.