土壤结构改良剂对皖南旱地红壤水分特征的影响

目的]研究土壤结构改良剂对皖南旱地红壤孔隙、容重及水分特征的影响,为皖南旱地红壤改良、提高土壤持水保水与抗旱保墒性能提供依据。方法]采用硅藻土(通气性Si改良剂)、泡沫沙类改良剂(T20)和无机矿石类改良剂(G20)等3种土壤结构改良剂,设置1%,2%,5%与10%的4个添加比例,进行土壤物理性状与水分特征测试。结果]硅藻土与T20均可显著降低土壤容重,而G20在添加5%与10%时才显著降低;硅藻土处理土壤毛管孔隙度由52.1%增加到91.3%,优于T20和G20;硅藻土与T20的吸湿系数与凋萎湿度随用量呈先增加而后下降,而G20则随添加量增加而增加;土壤的饱和持水量与田间持水量均随土壤结构改良剂添加量的增加而增加,以硅藻土增加最多,T20次之,G20最少。随改良剂用量增加,土壤有效水及难效水均呈增加趋势,其中,硅藻土处理的难效水增加量显著高于T20与G20处理。结论]改良皖南旱地土壤水分需要根据改良剂材料的种类与用量来进行合理施加,必要时可以组合搭配使用,从而达到最优效果。

Effects of Soil Amendments on Water Characteristics in Red Soil of Upland in South Anhui Province

Objective] The aim of this study is to investigate the effects of soil amendments on soil porosity, bulk density and water characteristics of upland at South Anhui Province, in order to provide information for soil improvement, water availability and anti-drought.Methods] Three different kinds of soil amendments including diatomite(Si), foamed sand(T₂₀) and mineral amendment(G₂₀) were used and 4 addition rates of 1%, 2%, 5% and 10% were adopted in the batch experiment.Results] The addition of Si and T₂₀ reduced soil bulk density significantly, however, the addition of G₂₀ showed a significant effect only at the addition rate of 5% and 10%. Soil porosity increased from 52.1% to 91.3% by Si treatment, which was better than T₂₀ and G₂₀ treatment. Soil moisture absorption coefficient and wilting moisture increased first and then decreased with the application amount of Si and T₂₀. In contrast, soil moisture absorption coefficient and wilting moisture increased linearly with the application amount of G₂₀. Soil saturation water capacity and field water capacity increased with the application amount of three amendments, and the increase trend was largest by application of Si, followed by T₂₀ and G₂₀. In addition, soil available water and hard available water increased with soil amendment addition rate. The treatment of Si on hard available water was better than T₂₀ and G₂₀.Conclusion] The water characteristics of upland soil of South Anhui Province should be improved according to the type and amount of soil amendment. In order to achieve an ideal effect, the combination of various soil amendments should be taken into account.