Effect of crop residue biochar on soil acidity amelioration in strongly acidic tea garden soils |
| |
| Authors: | L Wang C R Butterly Y Wang H M S K Herath Y G Xi X J Xiao |
| |
| Institution: | 1. Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, , Nanjing, 210042 China;2. Department of Agricultural Sciences, La Trobe University, , Bundoora, Vic., 3086 Australia;3. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, , Nanjing, 210008 China;4. Department of Export Agriculture, Faculty of Animal Science and Export Agriculture, Uva Wellassa University, , Badulla, 9000 Sri Lanka;5. New Zealand Biochar Research Centre, Institute of Natural Resources, Massey University, , Palmerston North, 4442 New Zealand |
| |
| Abstract: | Strongly acidic soil (e.g. pH < 5.0) is detrimental to tea productivity and quality. Wheat, rice and peanut biochar produced at low temperature (max 300 °C) and differing in alkalinity content were incorporated into Xuan‐cheng (Ultisol; initial pHsoil/water = 1/2.5 4.12) and Ying‐tan soil (Ultisol; initial pH soil/water = 1/2.5 4.75) at 10 and 20 g/kg (w/w) to quantify their liming effect and evaluate their effectiveness for acidity amelioration of tea garden soils. After a 65‐day incubation at 25 °C, biochar application significantly (P < 0.05) increased soil pH and exchangeable cations and reduced Al saturation of both tea soils. Association of H+ ions with biochar and decarboxylation processes was likely to be the main factor neutralizing soil acidity. Further, biochar application reduced acidity production from the N cycle. Significant (P < 0.05) increases in exchangeable cations and reductions in exchangeable acidity and Al saturation were observed as the rate of biochar increased, but there were no further effects on soil pH. The lack of change in soil pH at the higher biochar rate may be due to the displacement of exchangeable acidity and the high buffering capacity of biochar, thereby retarding a further liming effect. Hence, a significant linear correlation between reduced exchangeable acidity and alkalinity balance was found in biochar‐amended soils (P < 0.05). Low‐temperature biochar of crop residues is suggested as a potential amendment to ameliorate acidic tea garden soils. |
| |
| Keywords: | Biochar soil acidity pH amelioration tea soils |
|
|
