No tillage and crop rotation effects on soil aggregation and organic carbon in a Rhodic Ferralsol from southern Brazil
No tillage and crop rotation effects on soil aggregation and organic carbon in a Rhodic Ferralsol from southern Brazil
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DOI：
10.1016/j.still.2004.03.006
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发表时间：
2005
影响因子：
6.5
通讯作者：
B. Madari;P. Machado;E. Torres;A. Andrade;L. I. O. Valencia
中科院分区：
文献类型：
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作者：
B. Madari;P. Machado;E. Torres;A. Andrade;L. I. O. Valencia
在巴西，免耕是一种土壤保持做法，现在被包括小农在内的农民广泛采用。NT和传统耕作（圆盘犁，然后由两个光盘harrowings，CT）的影响进行了研究，从巴西南部的粘土Rhodic Ferralsol在不同的作物轮作的聚集特性。以次生林下相同土壤类型为参照。在四个取样层（0-5、5-10、10-20、20- 30 cm）使用一系列八个筛子（8、4、2、1、0.5、0.25、0.125、0.053 mm）通过湿筛分离大骨料和微骨料类别。土壤一般具有较高的结构稳定性。在0-5cm土层，森林土壤的平均粒径（MWD，11.1mm）和大团聚体中的总有机碳（TOC，39 gkg-1土壤）最高。NT土壤团聚体粒径和TOC的分布比CT更接近于森林土壤。不同耕作制度之间的差异最明显的是表层土壤（0-5cm）。在这一层中，NT具有更高的骨料稳定性（ASNT：96%; ASCT：89%），具有更高的骨料粒度分布值（MWDNT：7.9mm，MWDCT：4.3mm），并且在所有骨料粒度级别中的TOC平均比CT高28%。NT下土壤大团聚体中TOC含量较高（NT：22 gkg −1; CT：13 gkg −1）。轮作对土壤团聚体分布和TOC没有显著影响。通过增加大团聚体，NT增加了土壤有机碳的积累。
In Brazil, no tillage (NT) is a soil conservation practice now widely adopted by farmers, including smallholders. The effect of NT and conventional tillage (disc ploughing followed by two light disc harrowings, CT) was investigated on the aggregation properties of a clayey Rhodic Ferralsol from southern Brazil under different crop rotations. The same soil type under secondary forest was used as reference. Macro- and microaggregate classes were separated by wet sieving using a series of eight sieves (8, 4, 2, 1, 0.5, 0.25, 0.125, 0.053mm) at four sampling layers (0–5, 5–10, 10–20, 20–30cm). The soil in general had high structural stability. At 0–5cm, meanweight diameter (MWD, 11.1mm) and total organic C in macroaggregates (TOC, 39gkg−1soil) were highest for the forest soil. Soil under NT had a more similar distribution of aggregate size classes and TOC to the forest soil than CT. The most pronounced difference between tillage systems was observed in the surface soil layer (0–5cm). In this layer, NT had higher aggregate stability (ASNT: 96%; ASCT: 89%), had higher values of aggregate size distribution (MWDNT: 7.9mm, MWDCT: 4.3mm), and had on average 28% greater TOC in all aggregate size classes than CT. Soil under NT had greater TOC in macroaggregates (NT: 22gkg−1; CT: 13gkg−1). Crop rotation did not have a significant effect on soil aggregate distribution and TOC. By increasing macroaggregation NT increased organic carbon accumulation in soil.