Agronomy College, Agricultural University of Shenyang, Shenyang, China.
Research Institute of Agricultural Resources and Environment, Jilin Academy of Agricultural Science, Changchun, China.
PLoS One. 2018 Jun 28;13(6):e0199523. doi: 10.1371/journal.pone.0199523. eCollection 2018.
Soil tillage can affect the stability and formation of soil aggregates by disrupting soil structure. Frequent tillage deteriorates soil structure and weakens soil aggregates, causing them to be susceptible to decay. Different types of tillage systems affect soil physical properties and organic matter content, in turn influencing the formation of aggregates. The objective of this study was to evaluate the effect of long-term tillage on soil aggregates and aggregate-associated carbon in a black soil of Northeast China and to identify the optimal conservation tillage in this system. This research was conducted on a long-term tillage experimental field established in 1983 at the Jilin Academy of Agricultural Sciences, Gongzhuling, China. Plots were treated with four tillage systems including no tillage (NT), spacing tillage (ST), moldboard plowing (MP), and conventional tillage (CT). We took samples every 10cm from 0-60cm depth and demonstrated that water-stable soil aggregates >0.25mm in diameter accounted for over 66.0% of total aggregates for all tillage treatments, and the percentage for the ST treatment was 34.5% higher than in the other treatments. The NT treatment had the highest effect at 0-10cm depth, while the effect for the ST treatment was highest at 0-30cm. SOC storage decreased with soil depth, with a significant accumulation at 0-20cm depth. Across treatments, aggregate-associated C at a depth of 0-10cm was higher in the NT and ST treatments than in the MP and CT treatments. The advantage of the NT treatment weakened with soil depth, while the amount of aggregate-associated C remained higher for the ST treatment. There were more macro-aggregates in the ST and NT treatments than in the MP and CT treatments, while the MP and CT treatments had more micro-aggregates. The sum of macro-aggregate contributing rates for soil organic C (SOC) was significantly superior to that of the micro-aggregates. Water-stable aggregates increased by 34.5% in the ST treatment, effectively improving the soil structure. Furthermore, 0.25-1.00 and 1-2mm aggregates had the highest SOC storage and responded rapidly to the various tillage treatments. Hence, they can serve as indicators for the long-term influence of different tillage treatments on the distribution of aggregates and SOC.
土壤耕作可以通过破坏土壤结构来影响土壤团聚体的稳定性和形成。频繁的耕作会恶化土壤结构，削弱土壤团聚体，使其容易腐烂。不同类型的耕作系统会影响土壤物理性质和有机质含量，从而影响团聚体的形成。本研究旨在评估长期耕作对中国东北黑土土壤团聚体和团聚体相关碳的影响，并确定该系统中最佳的保护性耕作方式。本研究在中国吉林省公主岭市吉林农业科学院于 1983 年建立的长期耕作试验场进行。试验田采用免耕（NT）、垄作（ST）、铧式犁耕（MP）和常规耕（CT）四种耕作制度进行处理。我们从 0-60cm 深度每隔 10cm 取一个样本，结果表明，直径大于 0.25mm 的水稳性土壤团聚体占所有耕作处理的总团聚体的 66.0%以上，ST 处理的比例比其他处理高 34.5%。NT 处理在 0-10cm 深度的效果最高，而 ST 处理在 0-30cm 深度的效果最高。SOC 储存随土壤深度的增加而减少，在 0-20cm 深度有明显的积累。在所有处理中，0-10cm 深度的团聚体相关 C 在 NT 和 ST 处理中高于 MP 和 CT 处理。NT 处理的优势随着土壤深度的增加而减弱，而 ST 处理的团聚体相关 C 含量仍然较高。ST 和 NT 处理中的大团聚体多于 MP 和 CT 处理，而 MP 和 CT 处理中的微团聚体较多。大团聚体对土壤有机碳（SOC）的贡献率之和明显优于微团聚体。ST 处理的水稳性团聚体增加了 34.5%，有效地改善了土壤结构。此外，0.25-1.00 和 1-2mm 团聚体具有最高的 SOC 储存量，并对各种耕作处理有快速响应。因此，它们可以作为不同耕作处理对团聚体和 SOC 分布长期影响的指标。
