微咸水灌溉下不同生物炭对盐碱土水盐运移的影响

Impact of Biochar Amendment and Brackish Water Irrigation on Water and Salt Movement in Saline-alkaline Soil

【目的】合理利用黄河三角洲地区微咸水资源改良盐碱地。【方法】以黄河三角洲地区中度盐碱土为研究对象,进行室内一维入渗试验,探讨在微咸水灌溉基础上掺加小麦/玉米秸秆生物炭对盐碱土水盐运移和pH值的影响。试验共设置10个处理:CK(去离子水)、X1(10 t/hm^(2)小麦秸秆生物炭)、X2(20 t/hm^(2)小麦秸秆生物炭)、Y1(10 t/hm^(2)玉米秸秆生物炭)、Y2(20 t/hm^(2)玉米秸秆生物炭)、W(3 g/L微咸水)、WX1、WX2、WY1、WY2。【结果】微咸水灌溉条件下掺加生物炭提高了土壤入渗能力,增加了土壤保水能力,且掺加小麦秸秆生物炭的入渗性能与保水效果优于掺加玉米秸秆生物炭,其中WX1处理效果最优;微咸水灌溉条件下掺加生物炭有利于土壤盐分的淋洗,含盐量较微咸水灌溉处理降低了7.30%~10.44%,且掺加小麦秸秆生物炭降盐效果优于掺加玉米秸秆生物炭,其中WX1处理脱盐效果最优,脱盐率达53.74%;微咸水灌溉条件下掺加生物炭增加了土壤pH值,但与淡水灌溉无明显差异,且经小麦秸秆生物炭处理的土壤p H值均低于玉米秸秆生物炭,其中WX2处理效果最好。【结论】在3 g/L微咸水灌溉条件下,添加10 t/hm^(2)的小麦秸秆生物炭对黄河三角洲地区中度盐碱土改良效果较好。

【Objective】Biochar amendment has been widely used to improve soil quality and remediate soil contamination.The objective of this paper is to elucidate the impact of its combination with brackish water irrigation on water flow and salt transport in saline-alkaline soils in the Yellow River Delta.【Method】The experiment was conducted using soil columns.Soil taken from the delta was amended with biochar of wheat or maize straw respectively.There were 10 treatments by applying 10 t/hm^(2)(X1)and 20 t/hm^(2)(X2)of wheat biochar(X1),or 10 t/hm^(2)(Y1)and 20 t/hm^(2)(Y2)of maize biochar.The control was irrigation with deionized water(CK).The concentration of the brackish water was 3 g/L.In each treatment,we measured the movement of water,salt and soil pH.【Result】Amending soil with biochar combined with brackish water irrigation improved soil infiltration capacity and water retention in the soil.The wheat straw biochar worked better in improving infiltration than the maize straw biochar.Biochar amendment combined with brackish water irrigation also facilitated salt leaching,reducing salt content in the soil by 7.3%to 10.44%,compared to the CK.Wheat straw biochar worked better in de-salinizing the soil than maize straw biochar,especially the X1 whose desalination rate was 53.74%.The addition of biochar combined with brackish water irrigation increased soil pH,albeit not significantly,especially the maize straw biochar in X2 which affects soil pH most.【Conclusion】Amending the soil with 10 t/hm^(2) of wheat straw biochar combined with brackish water irrigation was effective to improve the quality of the saline soils in the Yellow River Delta region.Results of this study provide guidance to sustainably utilize brackish water and biochar to improve productivity of the saline-alkaline soils in Yellow River delta and areas with similar conditions.