施用生物炭对咸水滴灌棉田土壤理化性质及酶活性的影响

Effects of biochar application on soil physicochemical properties and enzyme activities in saline drip irrigation cotton field

【目的】淡水资源不足是限制干旱区农业可持续发展的重要因素,咸水灌溉在缓解淡水资源短缺、维持作物生长的同时,也加剧了土壤次生盐渍化的风险,合理利用咸水资源、改善土壤性质、提高作物产量是干旱区农业可持续发展的重要目标。【方法】试验设置灌溉水盐度和有机物料两个因素,灌溉水盐度(电导率,ECw)设2个水平,为0.35 dS/m (淡水)和8.04 dS/m (咸水),分别用FW和SW表示;每个灌溉水盐度处理下分别设置对照、棉花秸秆和棉花秸秆生物炭3个处理,分别以CK、ST和BC来表示。【结果】与淡水灌溉相比,咸水灌溉增加土壤容重、含水量、盐分、总碳、全氮、速效磷含量和土壤脲酶活性,但土壤pH值、速效钾、蔗糖酶活性、碱性磷酸酶活性、芳基硫酸酯酶活性、土壤呼吸及棉花株高、生物量、氮素吸收和产量均呈降低趋势。生物炭和秸秆施用降低土壤容重,但增加土壤pH、总有机碳、全氮、速效磷和速效钾;淡水灌溉下土壤盐分差异不显著,但咸水灌溉下土壤盐分显著降低。与CK处理相比,BC和ST处理显著增加土壤蔗糖酶活性,总体上蔗糖酶活性分别较CK处理高38.65%和35.89%;ST处理显著增加碱性磷酸酶和芳基硫酸酯酶活性,总体上碱性磷酸酶和芳基硫酸酯酶活性分别较CK处理高35.90%和65.01%;土壤脲酶活性与3种酶活性呈相反趋势,尤其是在SW条件下,BC处理和ST处理较CK分别降低20.51%和2.91%。生物炭和秸秆施用也显著提高土壤基础呼吸,BC和ST处理的土壤基础呼吸分别较CK增加24.88%和27.03%。BC处理和ST处理均显著提高棉花株高、生物量、氮素吸收和产量,总体上,生物炭和秸秆施用后的棉花产量较对照提高9.09%和5.66%。【结论】生物炭和秸秆的施用改善土壤理化条件,增加土壤养分,促进了棉花对养分的吸收,提高棉花产量。

【Objective】 Fresh water scarcity becomes an important factor limiting the sustainable agriculture development in arid regions. Saline water irrigation not only alleviates the shortage of fresh water resources and maintains crop yield, but also increases the risks of soil secondary salinization, and the rational use of saline water resources, the improvement of soil properties and the increase of crop yield are the important goals of agricultural sustainable development in arid regions. 【Method】The experimental design was a 2×3 factorial with two water salinity levels( EC 0.35 and 8.04 dS/m, denoted as FW andSW, respectively) and three types of organic materials(contrast, cotton straw and biochar, denoted as CK, ST and BC, respectively). 【Result】Compared with the FW treatment, SW treatment significantly increased soil bulk density, water content, salt and total carbon, total nitrogen, available phosphorus and soil urease activity, however, SW treatment significantly decreased soil pH, available potassium content, invertase activity, alkaline phosphatase activity, arylsulfatase activity, soil respiration, cotton plant height, biomass, nitrogen uptake and yield. In general, BC and ST treatments decreased soil bulk density, soil salt, but increased soil pH, soil total carbon, total nitrogen, available phosphorus, available potassium content. BC and ST treatments significantly increased soil invertase activity, compared with CK, the BC and ST treatments increased invertase activity by 38.65% and 35.89%, respectively. ST treatments significantly increased alkaline phosphatase and arylsulfatase activity, compared with CK, the ST treatments increased alkaline phosphatase and arylsulfatase activity by 35.90% and 65.01%, respectively. However, BC and ST treatments significantly decreased soil urease activity, especially under salt water irrigation conditions, the BC and ST treatments decreased urease activity by 20.51% and 2.91% compared with CK, respectively. In addition, BC and ST treatments increased soil basal respiration, overall, compared with CK, the BC and ST treatments increased soil basal respiration by 24.88% and 27.03%, respectively. BC and ST treatments significantly increased cotton plant height, biomass, nitrogen uptake and yield, overall, the cotton yield in BC and ST treatment was 9.09% and 5.66% higher than that in CK treatment. 【Conclusion】The biochar and straw application significantly improved soil physical and chemical conditions, increased soil nutrients, promoted the absorption of nutrients by cotton and increased cotton yield.