不同轮作序列对旱地胡麻土壤有机碳稳定性的影响  

Effect of rotation sequence on stability of soil organic carbon in dry-land oil flax

作　　者：刘栋 崔政军 高玉红[1,2] 剡斌 张中凯[1,2] 吴兵 谢亚萍 牛俊义[1,2] LIU Dong;CUI Zheng-jun;GAO Yu-hong;YAN Bin;ZHANG Zhong-kai;WU Bing;XIE Ya-ping;NIU Jun-yi(Gansu Provincial Key Laboratory of Arid land Crop Science,Lanzhou 730070,China;College of Agronomy,Gansu Agricultural University,Lanzhou 730070,China;College of Life Sciences and Technology,Gansu Agricultural University,Lanzhou 730070,China;Gansu Academy of Agricultural Sciences,Lanzhou 730070,China)

机构地区：[1]甘肃省干旱生境作物学重点实验室,甘肃兰州730070 [2]甘肃农业大学农学院,甘肃兰州730070 [3]甘肃农业大学生命科学技术学院,甘肃兰州730070 [4]甘肃省农业科学院,甘肃兰州730070

出　　处：《草业学报》2018年第12期45-57,共13页Acta Prataculturae Sinica

基　　金：现代农业产业技术体系建设专项资金(CARS-17-GW-9);国家自然科学基金(31360315);甘肃农业大学伏羲杰出人才项目(Gaufx-02J05)资助

摘　　要：为了探索陇中黄土高原半干旱丘陵沟壑区胡麻轮作序列对土壤碳库的影响,2012-2016年通过4年定位试验,以连作为对照,研究了不同胡麻频率下的轮作序列(F:休闲;PWFW:25%Flax、马铃薯-小麦-胡麻-小麦;WFWP:25%Flax、小麦-胡麻-小麦-马铃薯;FWPF:50%Flax、胡麻-小麦-马铃薯-胡麻;WPFF:50%Flax、小麦-马铃薯-胡麻-胡麻;FFFF:100%Flax、胡麻-胡麻-胡麻-胡麻)对土壤团聚体、总有机碳(TOC)、土壤颗粒有机碳(POC)、土壤微生物碳(MBC)和氮(MBN)的影响。结果表明,休闲、不同轮作序列和低胡麻频率显著增加了0～30cm土层<0.25mm粒级的土壤团聚体含量、TOC和POC含量,而随胡麻频率的增加三者的含量呈下降趋势。其中,25%Flax处理下土壤团聚体含量较播前和休闲处理分别显著增加了2.02%～4.04%和9.56%～11.73%;土壤有机碳(SOC)较连作显著增加5.95%～7.48%。50%Flax处理下胡麻位置对土壤SOC影响显著,且轮作(FWPF)显著高于连作(WPFF)。0～60cm土层土壤SOC含量表现为休闲>播前≈25%Flax>50%Flax>100%Flax。与连作相比,轮作显著提高了0～10cm土层土壤TOC和POC含量,呈现表层富集现象。土壤POC含量表现为25%Flax≈休闲>50%Flax>100%Flax。此外,轮作换茬显著增加了土壤MBC含量,且随着胡麻频率的增加,0～30cm土层土壤MBC含量逐渐降低。与播前、休闲、轮作相比,连作显著降低土壤微生物碳氮比,50%Flax(WPFF)轮作序列和土层深度对土壤有机碳和微生物量的互作效应显著。综合来看,休闲可以显著改善土壤理化性状,25%胡麻频率的轮作序列利于保持土壤团聚体稳定性,增加土壤TOC、SOC和POC含量,而50%Flax轮作序列(WPFF)能够提高土壤微生物量和微生物碳氮比。表明25%胡麻频率的轮作序列均可维持土壤有机碳的稳定性,是旱地胡麻比较理想的轮作序列。The aim of this study was to determine the effects of the flax rotation sequence on the soil carbon pool in a dry-land oil flax cropping area.A field experiment was conducted in a typical semiarid gully area of the Loess Plateau from 2012 to 2016 to study the effects of six rotation sequences with different flax frequencies(fallow;PWFW:25%flax,potato-wheat-flax-wheat;WFWP:25%flax,wheat-flax-wheat-potato;FWPF:50%flax,flax-wheat-potato-flax;WPFF:50%flax,wheat-potato-flax-flax;FFFF:100%flax,flax-flax-flax-flax).We measured soil aggregates,total organic carbon(TOC),particulate organic carbon(POC),microbial biomass carbon(MBC),and nitrogen(MBN)in all the treatments.A continuous cropping treatment served as the control.The results showed that the fallow treatment and a lower frequency of flax significantly increased the<0.25 mm soil aggregate content,TOC content,and POC content in the 0-30 cm soil layer.All of these parameters decreased with increasing flax frequency.The soil aggregate contents in the 25%flax treatments were 2.02%-4.04%higher and 9.56%-11.73%than those pre-sowing and in the fallow treatment,respectively.The SOC was 5.95%-7.48%higher in the 25%flax treatments than in the continuous cropping treatment.In the 50%flax treatments,the timing of the flax crop in the rotation sequence significantly affected soil SOC.The SOC content was significantly higher in the FWPF treatment than in the WPFF treatment.The treatments could be ranked,from highest soil SOC content in the 0-60 cm layer to lowest,as follows:fallow>pre-sowing≈25%flax>50%flax>100%flax.Compared with continuous cropping,rotation significantly increased the soil TOC and POC contents in the 0-10 cm soil layer,consistent with the phenomenon of surface enrichment.The treatments could ranked,from highest soil POC content to lowest,as follows:25%flax≈fallow>50%flax>100%flax.In addition,crop rotation treatments significantly increased the soil MBC content.The soil MBC content in the 0-30 cm layer decreased gradually with increasing flax frequency.Compa

关 键 词：旱地胡麻 轮作序列 土壤有机碳 土壤微生物量 土壤团聚体 

分 类 号：S565.9[农业科学—作物学] S153