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生物质炭添加对红壤性水稻土重金属有效性及土壤质量的影响

温馨,陈效民*,郭碧林,景峰,胡世民,李恋卿   

  1. (南京农业大学资源与环境科学学院, 南京 210095)
  • 发布日期:2020-04-10

Effects of biochar addition on the availability of heavy metals and soil quality in red paddy soil.

WEN Xin, CHEN Xiao-min*, GUO Bi-lin, JING Feng, HU Shi-min, LI Lian-qing   

  1. (College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China).
  • Published:2020-04-10

摘要: 通过田间定位试验探讨了不同生物质炭添加量对红壤性水稻土理化性质、重金属有效性和土壤质量的影响。生物质炭于2017年水稻种植前一次性添加于耕作层(0~17 cm),分别设置5个不同处理:CK: 0 t·hm-2,A10: 10 t·hm-2,A20: 20 t·hm-2,A30: 30t·hm-2和A40: 40 t·hm-2,经种植两季水稻后于2018年9月采集耕作层(0~17 cm)和犁底层(17~29 cm)土壤,计算土壤质量指数(SQI),评价土壤质量。结果表明:在耕作层(0~17 cm)和犁底层(17~29 cm),随着生物质炭添加量的增加,土壤容重逐渐降低;土壤孔隙度、pH值、有机质和可溶性有机碳含量增加,铵态氮和有效磷分别在添加量为20和30 t·hm-2时达到最大值;土壤中脲酶、过氧化氢酶和蔗糖酶的活性降低;生物质炭能够降低有效态Cd、As和Pb的含量,在生物质炭添加量为40 t·hm-2时最低;在土壤耕作层(0~17 cm),有效态Cd、As和Pb含量分别与脲酶、土壤pH值和蔗糖酶呈显著线性相关;在土壤犁底层(17~29 cm),有效态Cd、As和Pb含量分别与脲酶、过氧化氢酶和有效磷含量呈显著线性相关;各处理的SQI由高到低依次为A40>A30>A20>A10>CK,对应的指数值分别为0.641、0.638、0.579、0.533和0.464。这表明,红壤性水稻土的土壤质量在生物质炭添加量为40 t·hm-2时,达到最佳。综上所述,生物质炭在添加第二年后,能够显著降低红壤性水稻土的有效态重金属含量,提高土壤质量。

Abstract: A field experiment was conducted to examine the impacts of biochar addition on soil physicochemical properties, concentrations of heavy metals, and soil quality of a red paddy soil in Hunan Province, China. Biochar was added at dosage of 0, 10, 20, 30, and 40 t·hm-2 before the rice was transplanted in 2017. Soil samples in tilled layer (0-17 cm) and plow solelayer (17-29 cm) were collected in September 2018. Soil quality was evaluated by soil quality index (SQI). The results showed that biochar addition reduced soil bulk density but increased soil porosity, soil pH, the concentrations of organic matter and dissolved organic carbon (DOC). The contents of ammonium and available phosphorus were the highest at the treatments of 10 and 30 t·hm-2. Biochar addition enhanced the activities of soil urease, catalase and sucrose. The concentrations of cadmium (Cd), arsenic (As) and lead (Pb) in the red paddy soil werereduced by biochar addition, especially at the 40 t·hm-2 treatment. The concentrations of heavy metals and their influence factors were analyzed by stepwise regression. In the tilled layer, the contents of available Cd, As and Pb were significantly correlated with urease activity, soil pH, and sucrose activity, respectively. However, the contents of available Cd, As and Pb were significantly correlated with urease, catalase activities and available phosphorus content in the plow sole layer, respectively. The values of SQI among treatments decreased in the order: A40>A30>A20>A10>CK, with corresponding value of 0.641, 0.638, 0.579, 0.533, and 0.464, respectively. This result indicates that the quality of red paddy soil was the highest at the application amount of biochar is 40 t·hm-2. In conclusion, biochar addition can effectively reduce the availability of heavy metals and improve soil quality.