轮耕对双季稻田耕层土壤养分库容及Cd含量的影响  

Effects of Rotational Tillage on Nutrient Storage Capacity and Cd Content in Tilth Soil of Double-cropping Rice Region

作　　者：汤文光[1] 肖小平[1] 张海林[2] 黄桂林 唐海明[1] 李超[1] 刘胜利 汪柯[1] TANG Wen-Guang;XIAO Xiao-Ping;ZHANG Hai-Lin;HUANG Gui-Lin;TANG Hai-Ming;LI Chao;LIU Sheng-Li;WANG Ke(Soil and Fertilizer Institute of Hunan Province,Changsha410125,Hunan,China;College of Agronomy and Biotechnology,China Agricultural University,Beijing100193,China)

机构地区：[1]湖南省土壤肥料研究所,湖南长沙410125 [2]中国农业大学农学院,北京100193

出　　处：《作物学报》2018年第1期105-114,共10页Acta Agronomica Sinica

基　　金：国家公益性行业(农业)科研专项(201503118);国家科技支撑计划项目(2013BAD07B11);湖南省农业科学院科技创新项目(2017JC46)资助~~

摘　　要：研究长期不同耕作措施下双季稻田土壤结构、养分及重金属含量的变化规律,对构建稻田合理耕层、提升耕地质量、促进粮食可持续丰产具有重要意义。2005—2014年在湖南醴陵双季稻田设置长期免耕(NT-NT)、长期旋耕(RT-RT)、长期翻耕(CT-CT)、翻免轮耕(CT-NT)和旋免轮耕(RT-NT)5种耕作方式定位试验,测定并分析不同耕作方式对耕层深度、土壤容重、土壤C、N、P、K养分含量、养分库容量及重金属Cd含量等的影响。结果表明,NT-NT由于长期没有动土,土壤容重较高,而RT-RT、CT-CT、CT-NT和RT-NT均使土壤容重值降到了较理想区间。CT-NT和RT-NT 0~5 cm耕层土壤有机碳、活性有机碳、全氮、碱解氮、有效磷、速效钾和Cd含量均显著低于NT-NT,而高于RT-RT、CT-CT,说明NT-NT在促进土壤养分向表层聚集的同时,也促进了土壤镉向表层聚集,且随着耕作频率的增加土壤表层养分及土壤镉均呈下降趋势。CT-NT和RT-NT 5~10 cm耕层土壤各养分含量均显著高于NT-NT,而10~20 cm耕层土壤各养分含量均低于RT-RT、CT-CT,说明轮耕促进了土壤养分积累并主要向土壤中层聚集。耕层厚度、有效养分总库容量及土壤Cd含量均表现为RT-RT、CT-CT>CT-NT、RT-NT>NT-NT,说明随着耕作频率减少土壤耕层逐渐变浅,有效养分总库容量逐渐变小,土壤总镉、有效镉含量也逐渐降低。本研究表明,长期免耕和长期翻(旋)耕均存在一定弊端,长期免耕虽然降低了土壤镉含量,但同时也降低了土壤养分库容,长期翻(旋)耕虽然增加了土壤养分库容,但同时也增加了土壤镉含量,而合理土壤轮耕既可改善土壤结构,促进土壤养分积累、增加土壤养分库容,又能适当降低土壤镉含量,改善土壤环境。It is important significance to construct and improve the quality paddy layer,promote the sustainable grain yield by studies on the soil structure,nutrient and heavy metal contents in double cropping paddy fields under different tillage measures.The long-term located experiments with five tillage treatments including no tillage(NT-NT),conventional tillage(CT-CT),rotary tillage(RT-RT),conventional tillage-no tillage(CT-NT),and rotary tillage-no tillage(RT-NT)were conducted in double-cropping rice paddy from2005to2014.The tilth soil depth,soil bulk density,soil carbon,nitrogen,phosphorus,potassium,nutrients pool and heavy metal Cd content in different tillage treatments were analyzed.The results showed that NT-NT had higher soil bulk density,however,RT-RT,CT-CT,CT-NT,and RT-NT reduced it to a ideal interval.Soil organic carbon,active organic carbon,total nitrogen,available nitrogen,available phosphorus,available potassium and Cd content of CT-NT and RT-NT in0-5cm topsoil were significantly lower than those of NT-NT,showing that nutrients and Cd were aggregated to the surface layer of soil and decreased with increasing frequency of farming.Soil nutrient contents of CT-NT and RT-NT were significantly higher than those of NT-NT in5-10cm topsoil,but lower than those of RT-RT,CT-CT in10-20cm topsoil,demonstrating that the rotational tillage was beneficial to accumulate nutrients,especially in middle soil layer.The order of topsoil thickness,total available nutrients pool and Cd content showed RT-RT>CT-CT>CT-NT,RT-NT>NT-NT,therefore,topsoil layers would shallow,total available nutrients pool,soil total Cd and available Cd would shrink gradually with reducing tillage frequency.Our results indicated that long-term with no tillage,conventional tillage or rotary tillage all have certain drawbacks,no-tillage reduces soil Cd content and soil nutrients pool,conventional tillage or rotary tillage increases soil nutrients pools and soil Cd content.Therefore,the reasonable soil rotational tillage could improve soil structure,promo

关 键 词：轮耕 水稻 土壤养分 库容量 重金属CD 

分 类 号：S158[农业科学—土壤学] S511.42[农业科学—农业基础科学]