生草对梨园土壤物理特性的影响

Effect of Planting Herbage on Soil Physical Properties of Pear Orchard

为了研究不同生草年限对梨园土壤物理特性的影响,以清耕为对照,研究冀中生草4a和生草8a梨园,在0—30cm土层内分层取样,测定土壤容重、孔隙度、保水和排水能力及团聚体含量等土壤物理特性,比较不同生草年限梨园土壤物理性质的变化特征。结果表明：生草处理土壤容重显著降低,土壤孔隙度、土壤含水量和排水能力显著增加,对0—10cm土层物理特性的影响最大,与清耕相比较,生草8a和生草4a处理,土壤容重分别降低7.18%和4.26%,土壤孔隙度分别增加44.77%和11.54%,土壤毛管持水量分别增加109.62%和32.91%,排水能力分别增加了56.62%和21.98%;生草处理显著降低了0—10cm土层粒径〉5mm机械稳定性团聚体和粒径〉2mm水稳性团聚体含量,显著增加了0—20cm土层粒径0.25~5mm机械稳定性团聚体含量,生草8a显著增加了0—30cm土层粒径0.25~2mm水稳性团聚体含量。短期生草对土壤容重、孔隙度和保水性改善明显,对水稳性团聚体影响较小,随着生草年限的增加,梨园土壤物理性状愈趋改善。

In order to discuss the effects of planting herbage on soil physical properties of pear orchard,the pear orchards with 4-year and 8-year herbage growing in Jizhong plain were chosen as research objects and pear orchard with clean tillage was selected as control.Stratified sampling was carried out in each 10 cm layer of 0—30cm soil layers in all pear orchards and the differences and the varieties of all kinds of soil physical properties like soil bulk density,porosity,water retention and drainage ability and soil aggregate content were analyzed to compare variation characteristics of soil physical properties of pear orchards with different years of herbage growing.The results showed that,herbage growing significantly reduced soil bulk density,while increased soil porosity,soil moisture content and drainage capacity.The effect of herbage planting on soil physical properties was the most remarkable in 0—10cm soil layer.Compared with control treatment（clean tillage）,4-year and 8-year herbage planting decreased soil bulk density by 7.18%and 4.26%,respectively,while increased soil porosity by 44.77% and 11.54%,respectively,increased soil capillary water holding capacity by 109.62%and 32.91%,respectively,and also increased soil drainage capacity by 56.62%and 21.98%,respectively.The content of mechanical stable aggregates（more than 5mm）and water stable aggregates（more than 2 mm）reduced significantly in 0—10cm soil layer of planting herbage treatments,while the content of mechanical stable aggregates（0.25~5mm）increased greatly in 0—20cm soil layer of planting herbage treatments.The content of water stable aggregates（0.25~2mm）increased significantly in0—30cm layer after 8years of herbage planting.The soil bulk density,porosity and water holding capacity were improved obviously,while the water stable aggregate content was not promoted clearly after short-term planting herbage.With the increase of herbage planting period,soil physical properties of pear orchard were improved increasingly.