秸秆添加与土壤基质势对棕壤压缩回弹特性的影响

土壤板结是农田土壤退化问题之一,秸秆还田是提高土壤有机质含量、改良土壤的重要措施。但秸秆还田和土壤基质势对土壤板结的影响尚不明确。试验设0,3,5 g/kg 3个秸秆添加量处理,以及高(1 000 kPa)、中(100 kPa)、和低(10 kPa)3个土壤基质势处理。通过固结试验,测定不同处理的压缩曲线并计算压缩回弹特性指标。结果表明:秸秆添加量、土壤基质势及其二者间的交互作用对压缩曲线最大曲率、预固结压力值、压缩指数和回弹指数的影响都达到显著性水平。预固结压力值、压缩指数和回弹指数均随着秸秆添加量的增加而增大,而最大曲率则随着秸秆增加量的提高而降低。土壤基质势与压缩曲线最大曲率、预固结压力值和压缩指数均呈正相关关系。回弹指数随着土壤基质势的增加呈现先降低后增加的趋势。秸秆添加有助于提高土壤回弹和抗压缩特性。

Effects of Straw Addition and Matric Potential on Brown Soil Compression and Resilience

Soil compaction is one of the problems of farmland soil degradation. Straw returning is an important measure to increase soil organic matter content and improve the soil. However, the effects of straw returning and soil matrix potential on soil compaction are still unclear. The experiment set three treatments with straw addition amount of 0, 3 and 5 g /kg, and three soil matrix potential treatments of 1 000, 100 and 10 kPa. The compression curves of different treatments were measured by the consolidation test and the compression and resilience characteristic indexes were calculated. The results showed that the effects of straw returning, soil matrix potential and their interaction on maximum curvature, pre-compression stress, compression index and resilience index reached significant levels. Pre-compression stress, compression index and resilience index all increased with the increasing of straw addition, while the maximum curvature showed the opposite trend. Soil matrix potential had a positive correlation with the maximum curvature, pre-compression stress and the compression index. With the increasing of soil matrix potential, resilience index decreased first and then increased. Straw addition could improve soil resilience and compression resistance.