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草业学报 ›› 2018, Vol. 27 ›› Issue (12): 45-57.DOI: 10.11686/cyxb2018097

• 研究论文 • 上一篇    下一篇

不同轮作序列对旱地胡麻土壤有机碳稳定性的影响

刘栋1, 2, 崔政军1, 2, 高玉红1, 2, *, 剡斌1, 2, 张中凯1, 2, 吴兵2, 3, 谢亚萍4, 牛俊义1, 2   

  1. 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
  • 收稿日期:2018-02-06 修回日期:2018-05-11 出版日期:2018-12-20 发布日期:2018-12-20
  • 通讯作者: E-mail:gaoyh@gsau.edu.cn
  • 作者简介:刘栋(1982-),男,甘肃宁县人,在读博士。E-mail: 286877765@qq.com
  • 基金资助:
    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)和甘肃农业大学伏羲杰出人才项目(Gaufx-02J05)资助。

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

LIU Dong1, 2, CUI Zheng-jun1, 2, GAO Yu-hong1, 2, *, YAN Bin1, 2, ZHANG Zhong-kai1, 2, WU Bing2, 3   

  1. 1.Gansu Provincial Key Laboratory of Arid land Crop Science, Lanzhou 730070, China;
    2.College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China;
    3.College of Life Sciences and Technology, Gansu Agricultural University, Lanzhou 730070, China; 4.Gansu Academy of Agricultural Sciences, Lanzhou 730070, China
  • Received:2018-02-06 Revised:2018-05-11 Online:2018-12-20 Published:2018-12-20
  • Contact: E-mail:gaoyh@gsau.edu.cn

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030 cm土层<0.25 mm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)。060 cm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010 cm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,030 cm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。

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

Abstract: 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. Compared with pre?sowing, fallow, and crop rotation treatments, continuous cropping significantly reduced the ratio of soil microbial C/N. The SOC and microbial biomass were significantly affected by the interaction between the 50% flax rotation sequence and soil depth. These results indicated that a fallow treatment could significantly improve the soil physical and chemical properties. The 25% flax rotation sequence could maintain the stability of soil aggregates and increase soil TOC, SOC, and POC contents. The 50% flax rotation sequence could improve the soil microbial biomass and the ratio of soil microbial C/N. Because the rotation sequence with 25% flax frequency could maintain the stability of SOC, it was identified as the ideal rotation sequence for dry?land oil flax crops.

Key words: dry?land oil flax, crop rotation sequence, soil organic carbon, microbial biomass, soil aggregate