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

Abstract

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： ① Compared 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%. ③ The 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.