机构地区:[1]广西农业科学院农业资源与环境研究所,南宁530007 [2]广西大学农学院,南宁530004 [3]广西农业科学院经济作物研究所,南宁530007
出 处:《土壤》2021年第2期368-374,共7页Soils
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”专项资金(2018221);广西科技计划项目(桂科AA17204078-2、桂科AD18281089)资助。
摘 要:绿肥还田是影响农田土壤有机质的重要手段,为探索绿肥还田对粉垄稻田土壤活性有机碳的影响,采用常耕和粉垄栽培水稻,以不施肥、单一施用化肥、同等肥力条件下单倍绿肥配施化肥和双倍绿肥配施化肥共4种施肥处理,系统开展粉垄耕作稻田土壤活性有机碳研究。结果表明:①粉垄耕作减少了稻田土壤总有机碳含量,提高绿肥还田量有助于粉垄稻田土壤总有机碳的提高,双倍绿肥还田下提高25.6%~60.1%,而单倍绿肥还田有助于剖面各层土壤总有机碳积累;②绿肥还田增加了粉垄稻田土壤活性有机碳含量,提高了土壤固碳水平;随着绿肥还田量的增加可有效提高粉垄稻田土壤碳库管理指数,粉垄条件下单倍绿肥还田低、中、高活性有机碳分别增加了28.4%~47.9%、37.3%~49.9%、30.1%~49.6%,而双倍绿肥还田时分别增加47.8%~64.3%、40.0%~61.3%、29.6%~59.7%;③粉垄耕作下的稻田土壤总有机碳和碳库管理指数在孕穗期及其之后,随生长时期呈线性变化规律,决定系数R2高达0.999。绿肥还田下粉垄稻田土壤非活性有机碳占比随土层厚度的增加呈缓慢降低趋势,决定系数R2达0.998~0.999,对土壤活性有机碳的纵向迁移和变化的潜在激发利用效率规律明显。可见,绿肥还田能有效增加粉垄稻田土壤有机碳储量和活性有机碳的稳定性,对调控稻田土壤碳库及改善土壤质量具有重要的促进作用。Green manure returning is an important way to affect soil organic matter in farmland.In this paper,paddy fields were cultivated under conventional tillage and smash ridging respectively and four fertilization modes were carried out in order to explore the effect of green manure returning on soil labile organic carbon(LOC)in paddy field under smash ridging,the fertilization modes included:(1)no fertilizer,(2)single chemical fertilizers,(3)single green manure with chemical fertilizers under same fertility as single chemical fertilizers,and (4)double green manure with chemical fertilizers under same fertility as single chemical fertilizers.The results showed that:(1)Smashing ridging reduced the content of soil total organic carbon(TOC).Increasing green manure returning promoted soil TOC content under smash ridging,in which double green manure returning increased soil TOC content by 25.6%-60.1%,while single green manure increased TOC contents in all layers of soil profiles.(2)Green manure returning increased the content of soil labile organic carbon(LOC)and improved soil carbon sequestration level under smash ridging,and increasing green manure also improved soil carbon pool management index(CPMI)under smash ridging.Under smash ridging,the contents of low,medium and high LOC were increased by 28.4%-47.9%,37.3%-49.9%and 30.1%-49.6%under single green manure returning,and by 47.8%-64.3%,40.0%-61.3%and 29.6%-59.7%under double green manure returning,respectively.(3)Soil TOC and CPMI under smash ridging changed linearly with the growth stages at and after booting stage(R2 was 0.999).Under smash ridging,with the increase of soil depth,the proportion of soil non-labile organic carbon(NLOC)with green manure returning showed a slow linear decrease(R2 was 0.998-0.999),indicating a regular effect of green manure returning on potential utilization efficiency of the vertical migration and change of soil LOC.Therefore,green manure returning can effectively increase soil organic carbon storage and the stability of labile organic car
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