白膜覆盖下增效氮肥对春玉米土壤质量、微生物代谢和生态功能多样性的影响

Effects of Enhanced⁃efficiency Nitrogen Fertilizers on Soil Quality,Microbial Metabolism,and Soil Ecosystem Multifunctionality of Spring Maize Under White Plastic Film Mulching

过量施用氮肥是威胁土壤健康和降低土壤多种功能的主要驱动力.增效氮肥(EENFs)[例如脲酶抑制剂(NBPT)、硝化抑制剂(DCD)和树脂包膜尿素(RCN)]已被证明是减少氮肥施用的有效措施.然而,增效氮肥对土壤质量(SQI)、微生物代谢特征和土壤生态功能多样性(EMF)的影响以及其内在关系还不清楚.因此,基于宁夏回族自治区固原市彭阳试验站于2019年开始的田间定位试验,研究了白膜覆盖下不同施肥策略[不施氮肥(N0)、矿物氮肥(N200)、DCD、NBPT和RCN]对SQI、酶化学计量比特征和EMF的影响.结果表明:①相比N0,N200和EENFs增加了TN、MBC和MBN含量;相比N0和N200,NBPT和DCD的SQI提高了59.97%~104.78%和43.28%~83.42%,而RCN的SQI无显著变化.②EENFs比N200能更好地缓解微生物碳和氮限制,并提高土壤生态功能多样性21.97%~51.53%.③土壤中的MBC、MBN、AN、AP和SWC是影响微生物碳限制、氮限制和土壤生态功能多样性的共同主要因素,且提高土壤质量和缓解微生物碳和氮限制有利于提高土壤生态功能多样性.综合来看,白膜覆盖下施用NBPT和DCD可短期内实现土壤健康和生态功能多样性的双赢,这可为当地优化施肥管理措施提供参考.

Excessive nitrogen fertilizer application is the main driving force threatening soil health and reducing multiple soil functions.The enhanced-efficiency nitrogen fertilizers(EENFs),such as urease inhibitors(NBPT),nitrification inhibitors(DCD),and coated controlled-release urea(RCN),have been proven to be effective measures for reducing nitrogen fertilizer application.However,the effects of EENFs on soil quality(SQI),microbial metabolic characteristics,and soil ecosystem multifunctionality(EMF)and their internal relationships are still unclear.Therefore,based on the field positioning experiment started in 2019 by Pengyang Experimental Station of Guyuan City,Ningxia Hui Autonomous Region,we studied the effects of different fertilization strategies(no nitrogen fertilizer(N0),mineral nitrogen fertilizer(N200),DCD,NBPT,and RCN)on SQI,soil enzyme stoichiometry,and EMF under white plastic film mulching.The results revealed that:①Compared with that under N0,N200 and EENFs increased soil total nitrogen(TN),microbial biomass carbon(MBC),and microbial biomass nitrogen(MBN)contents.Compared to the SQI of N0 and N200,that of NBPT and DCD significantly increased by 59.97%-104.78%and 43.28%-83.42%,respectively,while RCN showed no significant change.②EENFs can alleviate microbial carbon and nitrogen limitations better than N200 and increase soil EMF by 21.97%-51.53%.③The MBC,MBN,available nitrogen(AN),available phosphorus(AP),and water content(SWC)of soil factors were the common main factors affecting microbial C limitation,N limitation,and soil EMF.Moreover,the improvement in soil quality and alleviating microbial C and N limitation were conducive to improving soil EMF.Overall,the NBPT and DCD application under white plastic film mulching can achieve a win-win situation of soil health and EMF in the short term,which can provide references for optimizing local fertilization management measures.