有机肥等氮替代对双季稻根区土壤结构环境及根活力的影响  

Effects of nitrogen substitution isonitrogen substitution on soil structural environment and root viability in the root zone of double-cropping rice

作　　者：李诗 张俊辉[1] 胡钧铭[1,2] 周凤珏[2] 李婷婷[1] 郑富海 郑佳舜 徐美花 LI Shi;ZHANG Jun-hui;HU Jun-ming;ZHOU Feng-jue;LI Ting-ting;ZHENG Fu-hai;ZHENG Jia-shun;XU Mei-hua(Agricultural Resource and Environment Research Institute,Guangxi Academy of Agricultural Sciences/Guangxi Key Laboratory of Arable Land Conservation,Nanning,Guangxi 530007,China;College of Agriculture,Guangxi University,Nanning,Guangxi 530004,China)

机构地区：[1]广西农业科学院农业资源与环境研究所/广西耕地保育重点实验室,广西南宁530007 [2]广西大学农学院,广西南宁530004

出　　处：《南方农业学报》2023年第11期3206-3216,共11页Journal of Southern Agriculture

基　　金：国家自然科学基金项目(41661074);广西“新世纪十百千人才工程”专项(2018221);广西农业科学院基本科研业务专项(桂农科2021YT040)。

摘　　要：【目的】探究有机肥等氮替代对水稻根区土壤结构环境、土壤微生物量碳及水稻根系生长的影响,为南方集约化双季稻生产相匹配的减肥增效种植制度优化提供理论依据。【方法】依托广西南宁双季籼稻典型区环境,设不施肥对照(CK)、无机氮(T1,100%化肥)、无机氮+有机氮(T2,绿肥+化肥)和有机氮(T3,绿肥+生物炭+蚕沙+无氮化肥)4个定位处理。在水稻移栽后返青至晒田根系形成的关键期内,分别于移栽后7、14、21、35和42 d采集水稻植株和根区土壤样品,系统分析水稻根系生长及土壤团聚体结构和微生物量碳含量变化。【结果】等氮替代可促进土壤水稳性团聚体形成,增加微生物量碳含量。早稻季,各处理中小团聚体(II~V级)总含量表现为T2(21.44%)>T3(18.85%)>T1(13.4%)>CK(7.65%),T2和T3处理的微团聚体含量(VI~VII级)高于CK和T1处理,T2处理的土壤水稳性团聚体平均质量直径(MWD)低于其他处理;晚稻季,各处理中小团聚体(II~V级)总含量依次为T2(21.44%)>T3(18.85%)>CK(12.11%)>T1(7.70%),T2和T3处理的微团聚体(VI~VII级)含量较高、MWD较低;双季稻T2和T3处理的几何平均值径(GMD)均显著低于T1和CK处理(P<0.05,下同),微生物量碳含量依次为T2>T3>T1>CK。等氮替代改变水稻根体积与根系活力,增强了植株养分吸收力。早稻季,移栽后42 d根体积和根活跃吸收面积均表现为T2>T1>T3>CK;晚稻季,移栽后42d根体积表现与早稻季一致,根活跃吸收面积表现为T1>T2>CK>T3。等氮替代影响水稻根冠比和干物质积累。早稻季,随移栽时间的延长,各处理的根冠比整体呈先升后降的变化趋势,均在水稻移栽后21 d出现峰值;晚稻季,各处理的根冠比峰值不明显。移栽后42 d,植株干物质重在各处理间差异显著,均表现为T2>T1>T3>CK。【结论】绿肥、生物炭与蚕沙可促进土壤水稳性团聚体形成,增大微生物量碳含量,利于稻根生长发育,与种植制度匹�【Objective】The purpose of the study was to explore the effects of organic fertilizer isonitrogen substitution on the rice and root zone soil structural environment,soil microbial mass carbon,rice root growth,and to provide a theo‐retical basis for the optimization of reduced fertilizer enhanced efficiency planting system matched to intensive double-cropping rice production in the south.【Method】Based on the environment of a typical zone of double-cropping indica rice in Nanning,Guangxi,four types of localized treatments were set up:no fertilization control(CK),inorganic nitrogen(T1,100%chemical fertilizer),inorganic nitrogen with organic nitrogen(T2,green manure+chemical fertilizer),and organic nitrogen(T3,green manure+biochar+silkworm excrement+nitrogen-free chemical fertilizer).Rice plant samples and root zone soil samples were collected at 7,14,21,35 and 42 d after transplanting during the critical period from greening after transplanting to the formation of the root system in sunny fields.The growth of rice roots and changes in the structure of soil aggregates and microbial mass carbon content were systematically analyzed.【Result】Isonitrogen substitu‐tion promoted the formation of soil water-stable aggregates and increased the microbial mass carbon content.In the early rice season,the total content of small and medium-sized aggregates(classes II to V)in each treatment showed T2(21.44%)>T3(18.85%)>T1(13.4%)>CK(7.65%).The content of microaggregates(classes VI to VII)was higher in the T2 and T3 treatments than that in the CK and T1 treatments,and the mean weight diameter(MWD)of soil water-stable aggregates in the T2 treatment was lower than that in the other treatments.In the late rice season,the total content of small and medium-sized aggregates(classes II to V)in each treatment was in the order of T2(21.44%)>T3(18.85%)>CK(12.11%)>T1(7.70%),with higher microaggregate content and lower MWD in the T2 and T3 treatments(classes VI to VII).Geometric mean diameter(GMD)of both T2 and T3 treatments of do

关 键 词：双季稻 等氮替代 有机氮 根际土壤结构 根活力 干物质重 

分 类 号：S511.42[农业科学—作物学]