生物质炭对旱作农田土壤持水特性的影响

为确定添加生物质炭对旱作农田土壤持水特性的影响,在隆中黄土高原典型旱作农田区设置相关定位试验,对不同生物质炭输入水平的土壤容重、土壤孔隙度、土壤水分常数及土壤水分特征曲线进行测定。结果表明,生物质炭的添加能够减小土壤容重,增加土壤孔隙度。随着生物质炭输入水平的增加,土壤容重的减小及土壤孔隙度的增加幅度加大。生物质炭达到50t/hm~2时土壤结构变化最为明显,0—5,5—10,10—30cm土层中土壤容重相比对照分别减小7.01%,9.91%,16.60%,土壤毛管孔隙度分别增加19.47%,21.02%,29.94%;并且生物质炭的施入可以增加土壤饱和含水量、土壤田间持水量、土壤有效水分含量。随着生物质炭输入水平的不断加大,各水分常数呈现出上升趋势,但当生物质炭输入水平达到40t/hm~2后涨幅空间开始减小。说明生物质炭的添加能够提高旱作农田的持水性能,但输入水平达到40t/hm~2后,土壤持水性能趋于稳定。

Effect of Biochar on Soil Retention Ability in Dry Farmland

In order to illustrate the effect of biochar on soil retention ability in dry farmland,this study measured the soil bulk density,soil porosity,soil moisture constants and the soil water retention curve of the soil with different biochar addition through setting located experiment in typical dry farmland of the Loess Plateau.The results showed that biochar adding reduced soil bulk density,and increased soil porosity.With the increasing of the biochar adding,the reduction range of soil bulk density and the increasing extent of soil porosity were both enhanced.The change of soil structure was the most obvious when the adding amount of biochar reached 50 t/hm2.Soil bulk density of 0-5 cm,5-10 cm and 10-30 cm soil layers decreased by 7.01％,9.91％ and 16.60 ％ compared with control group,respectively,and soil capillary porosity increased by 19.47％,21.02％ and 29.94％ compared with control group,respectively.The biochar adding increased soil saturated soil water content,soil field capacity and soil effective moisture content.With the increasing of the biochar adding,all the soil moisture constants showed rising trends,but the increasing extent decreased when the biochar amount reached 40 t/hm2.This study suggests that the addition of biochar improved the water retention ability of dry farmland,but the retention ability of soil tended to be stable when the adding amount of biochar reached 40 t/hm2.