Effects of tillage on contents of organic carbon, nitrogen, water-stable aggregates and light fraction for four different long-term trials
Effects of tillage on contents of organic carbon, nitrogen, water-stable aggregates and light fraction for four different long-term trials
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DOI：
10.1016/j.geoderma.2012.07.005
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发表时间：
2013
期刊：
影响因子：
6.1
通讯作者：
R. Andruschkewitsch;D. Geisseler;H. Koch;B. Ludwig
中科院分区：
文献类型：
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作者：
R. Andruschkewitsch;D. Geisseler;H. Koch;B. Ludwig
土壤管理可能影响土壤中碳和氮的动态，但其基本过程尚不清楚。我们的目的是量化不同耕作处理对自由和封闭轻组分（分别为fLF和oLF）的数量和分布、水稳性宏观团聚体（>250μm）含量和有机碳（Corg）储量的影响。在德国黄土土壤上进行了四项长期耕作试验，分别采用甜菜和冬小麦轮作。试验的不同耕作处理为常规耕作（CT，至30cm）、覆盖耕作（MT，至10cm）和免耕（NT）。不同耕作方式18 ~ 25年后，分别在0 ~ 5cm、5 ~ 25cm和25 ~ 40cm深度取样。这四项长期耕作试验在不同土壤质地和气候条件下进行，结果一致。2004 ~ 2010年甜菜和冬小麦的平均产量，垄作和机栽处理均高于免耕处理，且在0 ~ 5cm土层中，免耕和机栽处理的土壤有机质含量显著高于免耕处理。根据等效土壤质量法（CT: 0 ~ 40, MT: 0 ~ 38, NT: 0 ~ 36cm）， MT处理的土壤密度显著高于CT和NT处理。在表层5cm处，NT和MT处理的fLF、oLF和宏观团聚体含量显著高于CT处理，而在5 ~ 25cm深度，CT和MT处理的oLF含量显著高于CT处理。大团聚体含量与fLF和oLF含量的相关性表明，大团聚体含量不受不同耕作方式的直接影响，而受有效生物量含量的影响，这可能是由于连作和轮作下作物产量增加带来的高生物量投入以及覆盖和翻耕带来的残茬投入的垂直分布。逐步多元线性回归分析表明，土壤粗粉含量是影响4个长期试验土壤宏观骨料含量的最重要因素，而粉土和粉土含量与宏观骨料含量呈负相关。
Soil management may affect C and N dynamics in soils, but the underlying processes are not well understood. Our objective was to quantify the impact of different tillage treatments on the amount and distribution of free and occluded light fractions (fLF and oLF, respectively), on the water-stable macro-aggregate (>250μm) contents, and on organic carbon (Corg) storage. Four long-term tillage trials were carried out on loess soils in Germany with sugar beet followed by two years of winter wheat as crop rotations. The different tillage treatments trialled were regular conventional tillage (CT, to 30cm), mulch tillage (MT, to 10cm) and no-tillage (NT). Soils were sampled in 0–5cm, 5–25cm and 25–40cm depth after 18–25years of the different tillage treatments. These four long-term tillage trials on plots differing in soil texture and climatic conditions revealed consistent results between them. Average crop yields of sugar beet and winter wheat from 2004 to 2010 were higher under CT and MT than under NT. The NT and MT treatments produced significantly higher Corgcontents than the CT treatment in 0–5cm soil depth. The Corgstocks in the sampled profile, based on the equivalent soil mass approach (CT: 0–40, MT: 0–38, NT: 0–36cm), were significantly higher for the MT treatment than for the CT and NT treatments. The fLF, oLF, and macro-aggregate contents were significantly higher for the NT and MT treatments than for the CT treatment in the top 5cm, whereas in 5–25cm depth, the oLF contents were significantly higher for the CT and MT treatments. The correlation of the macro-aggregate content against the fLF and oLF contents suggested that the macro-aggregate content is not directly influenced by the different tillage treatments but by the contents of available biomass, presumably due to the higher biomass input via higher crop yields under CT and MT and the vertical distribution of the residue input by mulching and plowing. Stepwise multiple linear regression analysis suggested that the Corgcontent was the most important factor influencing the macro-aggregate content in the soils of the four long-term trials, whereas the contents of fLF and silt were negatively related to the macro-aggregate content.