摘要
东北黑土区作为我国重要的粮食生产基地,近年来面临着土壤退化、肥力下降和粮食减产等诸多问题.优化施肥管理是维持或提升土壤肥力的一种重要措施,但不合理的肥料施用会促使养分损失和N_(2)O等温室气体排放,导致土壤退化和环境污染.为探明黑土N_(2)O排放对长期施用有机肥和化肥的响应及关键控制因素,采集吉林公主岭黑土长期定位试验(32 a)的施用有机肥主处理(M_(0),不施有机肥;M_(1),低量有机肥;M_(2),高量有机肥)和施用化肥副处理(CK,不施肥;N,化学氮肥;NPK,化学氮磷钾肥)共计9个处理(即每个施用有机肥水平下包含3个化肥施用水平)的表层土壤样品(0~20 cm),进行室内恒温恒湿培养(65%田间持水量25℃下培养21 d),并测定N_(2)O排放通量和土壤物理化学生物学性质.研究结果表明,长期施用有机肥和化肥显著增加了黑土N_(2)O排放.与M_(0)CK处理[(0.25±0.01)mg·kg^(−1),以N计,下同]相比,单施有机肥处理N_(2)O累计排放量显著提高了361%~456%[M_(1)CK和M_(2)CK处理分别为(1.17±0.02)mg·kg^(−1)和(1.41±0.02)mg·kg^(−1)],且N_(2)O排放随着有机肥施用量增加显著增强.与M_(0)CK处理相比,单施化肥处理N_(2)O累计排放量显著提高了96%~236%[M_(0)N和M_(0)NPK处理分别为(0.49±0.01)mg·kg^(−1)和(0.84±0.03)mg·kg^(−1)],且平衡施用化肥处理N_(2)O排放提升幅度明显高于单施氮肥处理.在M_(1)和M_(2)条件下,化肥施用对N_(2)O排放的影响程度减弱,说明有机肥施用缓解了化肥对N_(2)O排放的影响.单施有机肥显著提高了土壤及团聚体有机碳(SOC)和总氮(TN)、土壤微生物量碳氮含量,有机肥配施进一步提高土壤及团聚体SOC和TN含量.Pearson相关及路径分析结果表明,N_(2)O排放与土壤碳氮组分及微生物量碳氮含量显著正相关,长期施用有机肥和化肥主要通过影响土壤碳氮组分,改变微生物量和底物有效性调控N_(2)O排放.综上所述,施用有机肥通过增加土壤可利用碳氮库以及微生物生物量碳氮显著促进了N_(2)O排放.有机肥施用缓解了化肥对N_(2)O排放的促进作用,在施用化肥时应适量配施有机肥,以平衡肥力提升与氮素损失及温室气体排放的综合效应.
As an important grain production area in China,the Northeast Black Soil Region has experienced many problems,such as soil degradation,fertility decline,and grain yield reduction,in recent years.Optimizing fertilizer management is an important measure to maintain and enhance soil fertility.However,improper fertilizer application could aggravate nutrient losses and greenhouse gas N_(2)O emissions,thus leading to soil degradation and environmental pollution.The objectives of the present study were to investigate the response of N_(2)O emission from black soil to long-term application of organic and chemical fertilizers and the key controlling factors.Soil samples(0-20 cm)were collected from a total of nine treatments,including organic fertilizer as the primary treatment(M_(0)-no organic fertilizer;M_(1)-low organic fertilizer;M_(2)-high organic fertilizer)and chemical fertilizer as the secondary treatment(CK-no fertilizer;N-chemical nitrogen fertilizer;NPK-chemical nitrogen,phosphorus,and potassium fertilizer),in a long-term experiment(32 years)on the black soil of Gongzhuling,Jilin Province.The soil samples were incubated at 25℃with 65%field water holding capacity for 21 days,and N_(2)O emission and soil physico-chemical biological properties were determined.The results showed that long-term application of organic and chemical fertilizers notably increased N_(2)O emissions from black soil.Compared to those from the M_(0)CK treatment[(0.25±0.01)mg·kg^(−1),in terms of N,the same as below],the cumulative N_(2)O emissions from the only organic fertilizer treatment significantly increased by 361%-456%[(1.17±0.02)mg·kg^(−1)and(1.41±0.02)mg·kg^(−1)for the M_(1)CK and M_(2)CK treatments,respectively].Furthermore,the N_(2)O emissions strongly increased with increasing organic fertilizer application amounts.Cumulative N_(2)O emissions were significantly higher in the chemical fertilizer treatments by 96%-236%[(0.49±0.01)mg·kg^(−1)and(0.84±0.03)mg·kg^(−1)for the M_(0)N and M_(0)NPK treatments,respectively]compared to those in the M_(0)CK treatments.Moreover,the increased N_(2)O emissions due to fertilizers application were significantly larger in the M_(0)NPK relative to M_(0)N treatments.The positive effects of chemical fertilizer application on N_(2)O emission decreased under organic fertilizer amendments(M_(1) and M_(2)),indicating that organic fertilizer application alleviated increased N_(2)O emission because of chemical fertilization.The application of organic fertilizers significantly increased bulk soil,aggregate organic carbon(SOC),total nitrogen(TN),and soil microbial carbon and nitrogen contents.The application of organic combined with chemical fertilizers further increased SOC and TN contents in bulk soil and aggregates.Pearson correlation and path model analyses showed that the N_(2)O emission was positively correlated with soil carbon and nitrogen fractions and microbial carbon and nitrogen contents among organic and chemical fertilizer treatments.Long-term application of organic and chemical fertilizers strongly regulated N_(2)O emissions via affecting the distribution of carbon and nitrogen contents in soil fractions and changing microbial biomass and substrate availability.In conclusion,the application of organic fertilizers could significantly facilitate N_(2)O emission by increasing the available soil carbon and nitrogen pools as well as microbial carbon and nitrogen contents.The application of organic fertilizers mitigated the positive effects of chemical fertilizers on N_(2)O emissions.Appropriate amounts of organic fertilizers should be used when applying chemical fertilizers,in order to balance the comprehensive effects of fertility improvement with nitrogen loss and greenhouse gas emissions.
作者
王昊
胡荣桂
林杉
高洪军
徐明岗
张文菊
邬磊
WANG Hao;HU Rong-gui;LIN Shan;GAO Hong-jun;XU Ming-gang;ZHANG Wen-ju;WU Lei(National Key Laboratory of Efficient Utilization of Arid and Semi-arid Farmland in North China,Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China;College of Resources and Environment,Huazhong Agricultural University,Wuhan 430072,China;Institute of Agricultural Resources and Environment,Jilin Academy of Agricultural Sciences,Changchun 130119,China)
出处
《环境科学》
北大核心
2025年第4期2621-2628,共8页
Environmental Science
基金
国家重点研发计划项目(2022YFD1500301)
中国农业科学院青年创新专项(Y2023QC16)。
