武均, 蔡立群, 齐鹏, 张仁陟, YeboahStephen, 岳丹, 高小龙. 不同耕作措施下旱作农田土壤团聚体中有机碳和全氮分布特征[J]. 中国生态农业学报(中英文), 2015, 23(3): 276-284. DOI: 10.13930/j.cnki.cjea.140863
引用本文: 武均, 蔡立群, 齐鹏, 张仁陟, YeboahStephen, 岳丹, 高小龙. 不同耕作措施下旱作农田土壤团聚体中有机碳和全氮分布特征[J]. 中国生态农业学报(中英文), 2015, 23(3): 276-284. DOI: 10.13930/j.cnki.cjea.140863
WU Jun, CAI Liqun, QI Peng, ZHANG Renzhi, Yeboah STEPHEN, YUE Dan, GAO Xiaolong. Distribution characteristics of organic carbon and total nitrogen in dry farmland soil aggregates under different tillage methods in the Loess Plateau of central Gansu Province[J]. Chinese Journal of Eco-Agriculture, 2015, 23(3): 276-284. DOI: 10.13930/j.cnki.cjea.140863
Citation: WU Jun, CAI Liqun, QI Peng, ZHANG Renzhi, Yeboah STEPHEN, YUE Dan, GAO Xiaolong. Distribution characteristics of organic carbon and total nitrogen in dry farmland soil aggregates under different tillage methods in the Loess Plateau of central Gansu Province[J]. Chinese Journal of Eco-Agriculture, 2015, 23(3): 276-284. DOI: 10.13930/j.cnki.cjea.140863

不同耕作措施下旱作农田土壤团聚体中有机碳和全氮分布特征

Distribution characteristics of organic carbon and total nitrogen in dry farmland soil aggregates under different tillage methods in the Loess Plateau of central Gansu Province

  • 摘要: 以连续进行12年的保护性耕作长期定位试验为研究对象, 探索了传统耕作(T)、传统耕作+秸秆还田(TS)、免耕不覆盖(NT)、免耕+秸秆覆盖(NTS)4种耕作措施对陇中黄土高原旱作农田豌豆 小麦双序列轮作系统的土壤团聚体中有机碳和全氮分布特征的影响。结果表明: 各处理均以≥0.25 mm团聚体为优势团聚体, 且≥0.25 mm团聚体含量随土层深度增加而增加, 而其他粒径团聚体含量随土层深度的变化并无明显规律。较之T处理, TS、NT、NTS处理均可提升≥0.25 mm团聚体含量和平均重量直径, NTS处理提升效果最明显。TS、NT、NTS 处理土壤有机碳和全氮含量均高于T处理, 其中TS、NTS处理显著高于T处理, NTS处理高于TS处理; 各处理土壤有机碳和全氮含量均随土层增加而减小。较之T处理, NT、TS、NTS处理可不同程度提高各粒径团聚体中有机碳和全氮含量, NTS处理的含量最高; 各粒径团聚体中有机碳和全氮含量均随土层深度增加而减小; 同时, 团聚体中有机碳和全氮含量随粒径减小而增加。2~5 mm和0.25~2 mm和≥5 mm团聚体含量与相应粒径团聚体有机碳含量呈极显著正相关、极显著正相关和极显著负相关; 0.25~2 mm和≥5 mm团聚体含量与相应级别团聚体全氮含量分别呈极显著正相关和显著负相关。T处理不同粒径团聚体有机碳和全氮贡献率按其大小排序均为(<0.25 mm)>(≥5 mm)>(0.25~2 mm)>(2~5 mm), 其他3种耕作措施各粒径团聚体有机碳和全氮贡献率在各土层中的排序各有不同, 并无明显规律。

     

    Abstract: A 12-year local experiment of spring wheat-pea rotation system was conducted in dry farmlands of the Loess Plateau in central Gansu. The aim of the study was to determine the distribution characteristics of soil organic carbon and total nitrogen in soil aggregates. The treatments consisted of four tillage practices ― conventional tillage without straw mulch (T), conventional tillage with straw incorporation (TS), no-tillage without straw mulching (NT) and no-tillage with straw mulching (NTS). The experimental set-up was a Randomized Complete Block design with three replications. The soil samples were taken at three different soil depths (0 5 cm, 5 10 cm and 10 30 cm) per plot. The results showed that the ≥0.25 mm aggregates of soil were the dominant aggregates, whose content increased with increasing soil depth. While increase in the content of ≥0.25 mm aggregates was regular, changes in the ≥5 mm, 2 5 mm, 0.25 2 mm aggregates were irregular. Compared to T treatment, NT, TS and NTS treatments increased the ≥0.25 mm aggregates content and mean weight diameter (MWD) of aggregates, and NTS had the highest effects. With increasing soil depth, MWD of all four treatments improved under pea→wheat→pea rotation sequence. However, the results under wheat→pea→wheat rotation sequence was different. MWD of T and NT treatments in three soil depths did not increase with increasing soil depth. However, MWD of TS and NTS treatments increased with increasing soil depth. Compared with T treatment, NT, TS and NTS treatments increased the contents of soil organic carbon and total nitrogen. NTS had the highest soil organic carbon and total nitrogen contents. NTS and TS were significantly higher (P < 5%) than T. The results showed that the contents of soil organic carbon and total nitrogen decreased with increasing soil depth. Compared with T treatment, NT, TS, NTS treatments improved soil organic carbon and total nitrogen in soil aggregates. NTS had the best for all the investigated soil depths. The results showed that with increasing soil depth, the contents of soil organic carbon and total nitrogen decreased in soil aggregates. Also the contents of soil organic carbon and total nitrogen decreased in soil aggregates with increasing aggregate size. The correlation between the 2 5 mm and 0.25 2 mm soil aggregates contents and their soil organic carbon content was significantly positive ― respectively with correlation coefficients of 0.493 and 0.559. The correlation between the ≥5 mm soil aggregate content and its soil organic carbon content was significantly negative ( 0.481). The correlation between the 0.25 2 mm and ≥5 mm soil aggregates contents and their total nitrogen contents was respectively significantly positive (0.590) and significantly negative ( 0.418). Therefore the size of the 0.25 2 mm soil aggregate was the major driver of soil organic and total nitrogen. The contributing rates of organic carbon and total nitrogen in different sized soil aggregates to soil organic carbon and total nitrogen in T treatment were in the order of (<0.25 mm) > (≥5 mm) > (0.25 2 mm) > (2 5 mm) in all the soil depths. The trends for the other treatments varied with different soil depths. Long-term conservation tillage increased soil stability, the ≥0.25 mm soil aggregate amount, soil aggregates mean weight diameter, soil organic carbon content and total nitrogen contents. NTS treatment enhanced amount of ≥0.25 mm soil aggregates improving soil organic carbon, total nitrogen and soil stability.

     

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