关键词: 生物炭, 酸性红壤, 茶园, 土壤养分, 硝态氮, 铵态氮, 全氮

Abstract: Soil erosion in mountain tea garden becomes serious in Fujian Province, and cultivation at high slope of tea garden causes fertilizer nutrient loss, as well as soil acidification. To find out the impacts of biochar on the changes of soil nutrient leaching of acid red loam soil of tea garden, this study estimated the losses of nutrient in the laboratory by leaching soil column simulation, 5 treatments were set up, including CK(C0N0), 2% biochar with convention fertilizer (C1N1), 5% biochar with convention fertilizer (C2N1), double the amount of fertilizer without biochar (C0N2), regular fertilizing with 2% biochar(C1N1) and regular fertilizing with 5% biochar(C2N1). The results showed that, under conventional fertilization, the volume of leachate decreased significantly with the increase of biochar applied, in addition, TN, NO-3-N and NH+4-N  significantly decreased. The leaching time showed that, the treatments with 2% and 5% biochar detected NO-3-N and NH+4-N later than the treatments without biochar, moreover, the peak of NO-3-N concentrations appeared earlier than NH+4-N. Compared to the treatment with conventional fertilization but without biochar (C0N1), using biochar (C1N1and C2N1) significantly increased soil pH and NO-3-N concentration reduced by 60% and 77%, respectively, NH+4-N concentration reduced by 40% and 39%, respectively. In terms of different nitrogen forms, C1N1和C2N1 detected NO-3-N was earlier than NH+4-N, which indicated the holding capacity of biochar to NH+4-N was better than that of NO-3-N. In conclusion, adding biochar to acid red soil for reducing nitrogen loss and improving soil nutrient content would be significance. These results provided the basis for soil improvement of acid red loam soil in tea garden.

Key words: biochar, acid red loam, tea garden, soil nutrient, nitrate nitrogen, ammonium nitrogen, total nitrogen