中国生态农业学报（中英文）2024，Vol.32Issue(5)：766-779,14.DOI:10.12357/cjea.20240116
长期不同施氮量下微生物残体氮对土壤氮库稳定性和玉米氮素吸收的影响
Impact of microbial residue nitrogen on soil nitrogen pool stability and maize nitrogen uptake under long-term varying nitrogen applications
摘要
Abstract
In farmland ecosystems,the application of chemical nitrogen(N)fertilizers is a crucial management strategy to ensure stable and high grain yields while maintaining the stability of soil N pools.Soil microorganisms play a pivotal role in both N mineral-ization and immobilization,thereby actively contributing to N retention and supply,which directly affects N uptake and utilization by crops.This study was conducted in the wheat-maize rotation field of the Luancheng Agro-Ecosystem Experimental Station of the Chinese Academy of Sciences.This study relied on a 14-year long-term positioning experiment with different N application rates.Three typical treatments were selected for N application rates during the maize season:150 kg(N)·hm-2(N150),200 kg(N)·hm-2(N200),and 300 kg(N)·hm-2(N300).Micro-plots were used to apply 15N-labeled N fertilizer to investigate the distribution of"old N"from soil and"new N"from fertilizer within soil N pools and their impact on crop N uptake and utilization.At harvest,the maize yield,total N uptake by the aboveground parts,and N uptake from fertilizers were measured.The contents of total N(TN),microbial residue N(MRN),fixed ammonium(FN),mineral N(NH4+-N+NO3-N,MN),and other organic N(ON)in the 0-20 cm soil layer were analyzed,along with the interception of 15N by different N pools.Multivariate regression and path analyses were used to estab-lish the relationships between various N pool forms and maize N uptake.The results indicated that maize yield,N uptake,and soil TN content were the highest under the N200 treatment,favoring high crop yields and soil N pool cultivation.Fertilizer N uptake and residue were higher under the N300 treatment than under the N200 treatment,suggesting a stronger"priming effect"under the N300 treatment,which induces greater mineralization and loss of soil"old N".The stability of soil TN pool was poor under the N300 treat-ment,with a higher degree of turnover.Among the TN pools,MRN was dominant,with the N200 treatment being significantly high-er than N150 treatment,contributing more than 50％of the TN.Fungal residue N(FRN)was the main contributor to MRN accumula-tion.The ratio of FRN to bacterial residual N(BRN)was higher in the N200 treatment than in the N150 and N300 treatments,indicat-ing that optimal N application could significantly enhance the contribution of fungi to N accumulation,thereby improving the stabil-ity of the soil N pool.Insufficient N application(N150)or excessive N application(N300)increased the contribution of bacteria to N accumulation,which was not conducive to stabilizing the soil N pool.The MN and FN contents were significantly higher in the N300 treatment than in other treatments,suggesting that excessive fertilization predominantly enhanced the active N pool.In conclusion,optimal N application can optimize the soil N pool distribution,promote the sequestration of N into microbial residue pools,signifi-cantly enhance the N immobilization capacity of soil microorganisms,and foster the benign operation of soil N retention and supply.This ensures maize N uptake and yield.The study provides a scientific basis for guiding farmland fertility improvement and N ferti-lizer reduction in the North China Plain.关键词
玉米/施氮量/15N标记/吸氮量/土壤氮库/微生物残体氮Key words
Maize/Nitrogen application rate/15N labeling/Nitrogen uptake amount/Soil nitrogen pool/Microbial residue nitrogen分类
农业科技引用本文复制引用
韩建,张玉铭,何红波,李俊娣,胡春胜,李晓欣,董文旭,刘秀萍,张丽娟..长期不同施氮量下微生物残体氮对土壤氮库稳定性和玉米氮素吸收的影响[J].中国生态农业学报（中英文）,2024,32(5):766-779,14.基金项目
国家重点研发计划项目(2022YFD1500302-3,2022YFD1901303-4)、河北省重点研发计划项目(22326410D,21323601D)和河北省自然科学基金项目(C2022503009)资助 This study was supported by the National Key R&D Program of China(2022YFD1500302-3,2022YFD1901303-4),the Key R&D Program of Hebei Province(22326410D,21323601D)and the Natural Science Foundation of Hebei Province(C2022503009). （2022YFD1500302-3,2022YFD1901303-4）
