中文摘要：

以东北典型黑土区耕地土壤为研究对象，通过对不同前期含水量下机械碾压处理后土壤干筛团聚体和水稳性团聚体粒级分布、破坏率（PAD0.25）、分形维数（D）、平均重量直径（MWD）、平均重量比表面积（MWSSA）等特征指标的测定和分析，对比研究了干湿处理条件下模拟机械作业过程中土壤团聚体特征的变化。结果表明：黑土耕作区0～30cm范围内团聚体组成上干筛团聚体以〉2mm粒级的团聚体比例最高，而水稳性团聚体则随着粒级的减小，比例逐渐增加。不同前期土壤含水量能够对机械压实黑土的团聚体组成分布、分形等特征产生影响，低含水量时，机械碾压在一定程度上能够促进土壤团聚体的团聚，但同等负荷下多次积累压实会削弱土壤的水稳定性和机械稳定性；而在高含水量时，机械碾压相对更易对黑土团聚体产生负效应，加剧破坏、抑制团聚，降低其水稳定性和机械稳定性。同时发现，MWSSA与其他常用团聚体特征值PA0.25，、MWD、D、PAD0.25的线性关系达到了极显著水平，说明MWSSA同样可以作为分析和研究土壤团聚体特征的有效指标。研究结果可为科学指导大机械作业提供理论依据。

英文摘要：

Influence of antecedent soil moisture content on features of soil aggregates of a typical black soil farmland in Northeast China compacted mechanically was investigated by analyzing distribution of dry and water-stable soil aggregates, percentage of aggregate disruption （PAD0.25）, fractal dimension （D）, mean weight diameter （MWD）, mean weight soil specific area （MWSSA）. Results show that dry aggregates over 2 mm were predominant in the black soil and the proportion of water-stable aggregates was increasing with declining particle size. Composition profile and fractal character of soil aggregates of compacted black soil were obviously affected by its previous soil moisture content. When soil moisture content was low, mechanical compaction promoted aggregation to a certain extent, but accumulated compaction of repeated mechanical operations with equal load reduced water stability and mechanical stability of the soil. However, when soil moisture content was high, mechanical operations were relatively more liable to create negative effect on soil aggregation in black soil, e.g. aggravating destruction, inhibiting aggregation, reducing their water stability and mechanical stability. Moreover, it was also discovered that MWSSA had extremely significant linear relationships with PA0.25, MWD, D and PAD0. 25, so MWSSA could also be cited an effective index in analyzing and studying soil aggregates. The findings may serve as theoretical basis for scientifically guiding operation of heavy machinery.