土壤混掺生物炭对微咸水蒸发特性的影响

为探究不同生物炭混掺量对微咸水蒸发特性的影响,采用离心机试验和室内土柱模拟试验,设置3个生物炭质量添加比例(B₀、B₂、B₄)和4个微咸水矿化度(W₀、W₁、W₃、W₅),分析不同处理对微咸水蒸发下的土壤水分特征曲线、孔隙分布、累积蒸发量、盐分运移、土壤温度日变幅的影响,并应用蒸发模型进行拟合分析。结果表明:生物炭和微咸水联合应用下能提高土壤持水能力,增加土壤中的较大孔隙和较小孔隙的比例;土壤累积蒸发量随着生物炭混掺量的增加先减少后增加,生物炭混掺量为2%时可以更好地抑制微咸水蒸发;Rose蒸发模型可以较好地拟合微咸水蒸发;土壤中混掺生物炭可以降低盐分表聚,使其在土壤中均匀分布;混掺生物炭可以有效降低土壤温度日变幅;相同生物炭施用量下,矿化度为3 g/L的微咸水,可以降低0—10 cm土层土壤平均温度,提高10—50 cm土层土壤平均温度。综合考虑各项指标,处理B₂W₃的生物炭和微咸水更适宜农田施用,为西北干旱地区更好地利用微咸水灌溉提供理论依据。

The Effect of Soil Mixed with Biochar on Brackish Water Evaporation Characteristics

The effects of different biochar mixing amounts on the evaporation characteristics of brackish water were investigated by centrifuge test and indoor soil column simulation test. Three biochar mass addition ratios (B₀, B₂ and B₄) and four brackish water salinity ratios (W₀, W₁, W₃ and W₅) were set up in the experiment. The effects of different treatments on soil water characteristic curve, pore distribution, cumulative evaporation, salt transport and daily variation of soil temperature under brackish water evaporation were analyzed, and the evaporation model was used for fitting analysis. The results showed that the combined application of biochar and brackish water could improve soil water holding capacity of soil and increase the proportion of larger and smaller pores in soil; The cumulative evaporation of soil water first decreased and then increased with the increase of biochar mixture, when the biochar mixture was 2%, brackish water evaporation could be inhibited better; Rose evaporation model could fit brackish water evaporation well; Biochar mixing in soil could reduce the surface accumulation of salt and make it evenly distributed in soil; Biochar could effectively reduce the diurnal variation of soil temperature; With the same amount of biochar application, brackish water with a salinity of 3 g/L could reduce the average soil temperature of 0-10 cm and increase the average soil temperature of 10-50 cm. Taking all the indexes into consideration, the biochar and brackish water treated with B₂W₃ are more suitable for farmland application, which provides a theoretical basis for better utilization of brackish water irrigation in arid areas of Northwest China.