生物炭施用对矿区污染农田土壤上油菜生长和重金属富集的影响

矿山的生产活动往往会造成周边农田的污染,而利用生物炭技术治理矿区周边污染农田土壤具有重要的现实意义。生物炭是指生物质在无氧或限氧条件下热裂解制备而成的一种细粒度、多孔性的环境友好型材料,其在调控温室气体排放,改良土壤性状,促进植物生长和控制环境污染物迁移转化方面应用潜力巨大。采用室内盆栽模拟实验,研究了不同水稻秸秆生物炭施用量（0、1%、5%）对郴州和龙岩地区矿山周边重金属污染的农田土壤的生化性状、油菜（Brassia campestris L.）产量、重金属累积和富集系数等的影响,为生物炭作为环境功能材料应用于矿山污染农田治理提供科学依据。结果表明：与对照相比,施加1%和5%生物炭均能提高土壤pH值和有机质质量分数,提升幅度随施用量的增加而升高,其中偏酸性的龙岩土壤的变化幅度更大;生物炭施用会影响土壤酶活性,5%生物炭处理下两种受试土壤中脲酶和过氧化物酶活性均显著提高,但酸性磷酸酶活性降低;龙岩土壤上的油菜产量在1%和5%生物炭施用处理下均显著提高,而郴州土壤上的油菜产量在1%生物炭处理下无显著变化,而在5%生物炭处理下降低了42.9%;生物炭施用影响了两种土壤上油菜可食部分重金属Cd、As和Pb的质量分数,但没有一致的规律;与对照相比,生物炭施用后郴州和龙岩土壤上油菜可食部分中Cd质量分数均出现下降趋势,但是仅5%生物炭处理的龙岩土壤具显著性差异;1%和5%生物炭施用处理使两种受试土壤上油菜可食部分Pb质量分数较对照处理显著降低（P〈0.05）,但降幅不同,郴州土壤降低了23.6%和22.0%,而偏酸性的龙岩土壤降低了82.1%和94.5%;生物炭施用后两种受试土壤上油菜可食部分As质量分数的变化不同,郴州土壤添加生物炭后油菜As质量分数呈上升趋势,且增量随生物炭施用量增加而升高,龙岩土壤则相反,1

Effects of biochar application on growth and typical metal accumulation of rape in mining contaminated soil

implications to use biochar technology to manage the contaminated soil in the surrounding farmland of mine. Biochar is a fine-grained, porous and environment-friendly material obtained from the pyrolysis of biomass under anaerobic or oxygen-limited conditions, and showing potential applications in improving soil quality, promoting plant growth, reducing greenhouse gas emissions and regulating pollutant behaviors. A pot experiment was carried out to study the effects of rice straw biochar with different application rate （0, 1%and 5%） on the soil biochemical traits, growth, typical heavy metals uptake and accumulation coefficients of rape （Brassia campestris L.） in two heavy metals contaminated soils which were from the farmland near mining area in Chenzhou and Longyan city. The results of this study will provide scientific basis for the management of contaminated soil in the surrounding farmland of mine. The results showed that biochar addition increased soil pH and organic matter, especially in acidic Longyan soil. The soil enzyme changed after biochar addition, the activity of urease and catalase significantly increased after 5% biochar addition, but the alkali phosphatase activities decreased. In Chenzhou soil, compared to the control treatment, the biomass of rape significantly decreased only under the treatment of 5%biochar addition. In Longyan soil, the biomass significantly increased after both 1%and 5%biochar addition. The concentrations of Cd, As and Pb in edible rape changed after biochar addition in two tested soils, but there was no consistent patterns. Compared to the control treatment, Cd concentration in edible rape decreased, but there was a significant difference only under the treatment of 5%biochar-amended Longyan soil. As for Pb concentrations, 1%and 5%biochar addition could significantly decreased its concentrations in edible rape , with different decreasing ranges of 23.6%and 22.0%in Chenzhou soil and 82.1%and 94.5%in acidic Longyan soil. As concentrations in edible rape differed in t