轮耕对豫北潮土速效养分及可溶性有机碳结构特性的影响

Effects of rotation tillage on available nutrients and structural characteristics of dissolved organic carbon of Fluvo-aquic soil in northern Henan Province

    摘要
  • 摘要: 本研究以豫北潮土为研究对象, 采用大田小区试验研究不同轮耕模式对不同深度土壤速效养分与可溶性有机碳结构特性的影响, 以筛选适合豫北潮土的轮耕模式。本研究于小麦季实施5种不同的耕作模式, 3年为一个周期: 1)连续旋耕(RT-RT-RT); 2)深耕-旋耕-旋耕(DT-RT-RT); 3)深耕-旋耕-条旋耕(DT-RT-SRT); 4)深耕-条旋耕-条旋耕(DT-SRT-SRT); 5)深耕-条旋耕-旋耕(DT-SRT-RT)。测定并分析土壤碱解氮、速效磷、速效钾、可溶性有机碳含量及其腐殖化程度、有机质分子量与聚合度、疏水组分比例、芳香化程度与分子量。结果显示, 各处理间的差异主要表现在0~40 cm土层。相较于RT-RT-RT, 轮耕处理对各项指标均有显著影响, 其中以DT-SRT-RT处理对各指标的影响最为突出, 具体表现为DT-SRT-RT处理显著增加了0~40 cm土层碱解氮、速效磷、速效钾含量(P<0.05), 最高增加17.8%、17.2%和19.6%。在0~40 cm土层中, DT-SRT-RT处理较RT-RT-RT最高增加了20.2%土壤可溶性有机碳含量(P<0.05)、53.1%腐殖化程度和27.4%疏水组分比例(P<0.05)。DT-RT-SRT处理较RT-RT-RT处理显著增加20~30 cm土层芳香化程度与分子量(P<0.05), 最高增加21.0%, 10~30 cm土层有机质分子量与聚合度显著降低36.7% (P<0.05)。土层深度与轮耕处理的单因素以及二者之间的交互效应均显著影响土壤速效养分和可溶性有机碳及其结构特性(P<0.05)。所有处理各指标间的相关性随土层深度的增加而减弱。综上所述, 相较于连续旋耕(RT-RT-RT), 深耕-条旋耕-旋耕模式(DT-SRT-RT)提高了土壤速效养分和可溶性有机碳含量, 增加可溶性有机碳的结构复杂性, 推荐为豫北潮土区适宜的轮耕模式。

     

    Abstract: Tillage is an important practice for improving soil quality. The effects of tillage on soil nutrient contents are well known. However, the understanding of the effects of tillage on soil dissolved organic carbon (DOC) and its structure is rare. This study aimed to select optimum tillage mode by exploring the effect of tillage mode on DOC and its structure in Fluvo-aquic soil in northern Henan Province. A field experiment was carried out using five treatments designed with different tillage rotation modes during the wheat season. The treatments were as follows: 1) continuous rotary tillage (RT-RT-RT); 2) deep tillage-rotary tillage-rotary tillage (DT-RT-RT); 3) deep tillage-rotary tillage-strip rotary tillage (DT-RT-SRT); 4) deep tillage-strip rotary tillage-strip rotary tillage (DT-SRT-SRT); 5) deep tillage-strip rotary tillage-rotary tillage (DT-SRT-RT). The contents of alkaline hydrolysis nitrogen (AN), available phosphorus (AP), available potassium (AK), DOC, degree of humification, molecular weight and polymerization degree of organic matter, proportion of hydrophobic components, degree of aromatization and molecular weight of soil were measured and analyzed. The results showed that the difference in all the indexes among treatments was mainly demonstrated in the 0–40 cm soil layer. Compared with those under RT-RT-RT in the 0–40 cm soil layer, the AN, AP, and AK increased by 17.8%, 17.2%, and 19.6% (P<0.05), respectively, under DT-SRT-RT, whereas the DOC content, degree of humification, and proportion of hydrophobic components increased by 20.2%, 53.1%, and 27.4% (P<0.05), respectively, under DT-SRT-RT. Compared with those under RT-RT-RT, the aromatization degree and molecular weight in the 20–30 cm soil layer increased by 21.0% (P<0.05), and the molecular weight and polymerization degree of organic matter in the 10–30 cm soil layer decreased by 36.7% (P<0.05) under DT-RT-SRT. Available soil nutrients and DOC and its structural characteristics were affected by soil depth, tillage mode, and the interaction between soil depths and tillage modes. The correlation among different indices decreased with increasing soil depth. In summary, compared with continuous rotary tillage, DT-SRT-RT improved soil available nutrients and DOC content and increased the complexity of the DOC structure. Therefore, the DT-SRT-RT mode was suggested as a suitable rotation tillage mode in the Fluvo-aquic soil areas of northern Henan.

     

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