长期有机无机氮肥配施对玉米-豇豆复种土壤团聚体碳含量和官能团分子结构的影响  

Effect of Long-term Organic and Inorganic Nitrogen Fertilization on Carbon Content and Molecular Structure of Functional Groups in Soil Aggregates in Maize-cowpea Cropping Systems

作　　者：吴梦琴 曹凑贵[1] 刘天奇 李成芳[1] WU Mengqin;CAO Cougui;LIU Tianqi;LI Chengfang(Key Laboratory of Crop Physiology,Ecology and Farming in the Middle Reaches of the Yangtze River,Ministry of Agriculture and Rural Affairs,China/College of Plant Science and Technology,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]农业农村部长江中游作物生理生态与耕作重点实验室/华中农业大学植物科学技术学院,武汉430070

出　　处：《土壤学报》2023年第6期1822-1831,共10页Acta Pedologica Sinica

基　　金：湖北省重点研发计划项目(2021BBA224);国家重点研发计划项目(2017YFD0301403)资助。

摘　　要：通过设置无机氮肥(IF)、有机氮肥(OM)、有机无机氮肥配施(IF+OM)等3个不同氮肥处理,探究长期(9年)施用不同氮肥对玉米-豇豆复种系统中土壤有机碳组分含量及官能团的影响,揭示土壤有机碳的积累规律。采用物理分组方法测定轻组颗粒有机碳(fPOC)、微团聚体内颗粒有机碳(iPOC)、微团聚体内粉黏粒有机碳(iSOC)和非闭蓄态粉黏粒有机碳(fSOC),并利用核磁共振波谱分析法测定土壤有机碳官能团结构。结果表明,与IF处理相比,OM和IF+OM处理显著提高土壤团聚体平均重量直径(MWD)和几何平均直径(GMD),且IF+OM处理下该作用更明显。相比IF处理,IF+OM处理明显提高了土壤有机碳、fPOC和iPOC的含量,但对iSOC和fSOC的含量无明显影响。与IF处理相比,IF+OM处理明显增加了烷基碳含量,但减少了芳香碳含量。路径分析表明,烷基碳/烷氧碳、疏水性、fPOC和iPOC碳含量与有机碳含量之间存在密切联系。总之,长期IF+OM有利于产量提高,增加fPOC和iPOC碳含量,优化团聚体的结构,增强土壤稳定性,提高土壤碳固定,增加有机碳储量。【Objective】Although many studies have reported the effects of long-term fertilizer application on soil organic carbon composition,molecular structure and functional group,few studies revealed the relationships between soil organic carbon,organic carbon composition and organic carbon functional groups under long-term fertilization conditions.Therefore,a field experiment with a maize-cowpea cropping rotation was conducted.The experiment included three treatments,i.e.,organic nitrogen(N)fertilizer(OM),inorganic N fertilizer(IF),and the combination of organic and inorganic N fertilizers(IF+OM).The effect of long-term(9 years)N fertilizer applications on organic carbon composition and molecular structure of soil aggregates were studied to reveal the accumulative mechanism of soil organic carbon.【Method】The soil was divided into 4 components by dry sieving method:>2 mm,2–0.25 mm,0.25–0.053 mm,and<0.053 mm,and then the mean weight diameter(MWD)and geometric mean diameter(GMD)were analyzed.The physical isolation method was used to measure free light particulate organic carbon(fPOC),intra-microaggregate particulate organic carbon(iPOC),silt-clay sized fraction organic carbon within microaggregates(iSOC)and free silt-clay sized fraction organic carbon(fSOC),and nuclear magnetic resonance spectroscopy was used to determine the functional group structure of soil organic carbon.【Result】The results showed that compared with IF treatment and OM treatment,IF+OM treatment significantly enhanced maize and cowpea yields after 9 years of continuous N fertilization.Moreover,compared with IF treatment,OM and IF+OM treatments significantly increased MWD and GMD,and the effect was more obvious under IF+OM treatment.This study shows that fPOC was the main component of the soil organic carbon fraction,ranging from 21.0 to 29.8 g·kg–1.The combination of organic and inorganic N fertilizers significantly enhanced the contents of soil organic carbon,fPOC and iPOC by 30.0%,41.9%and 23.5%relative to IF treatment,respectively,

关 键 词：有机无机氮肥配施 团聚体碳 有机碳组分 分子结构 

分 类 号：S153.6[农业科学—土壤学]