The key factors influencing pH buffering capacity of acid soils from tropical and subtropical regions, and effects of soil evolution and incorporation of biochars on pH buffering capacity were investigated to develop suitable methods to increase pH buffering capacity of acid soils.
Materials and methods
A total of 24 acid soils collected from southern China were used. The pH buffering capacity was determined using acid–base titration. The values of pH buffering capacity were obtained from the slope of titration curves of acid or alkali additions plotted against pH in the pH range 4.0–7.0. Two biochars were prepared from straws of peanut and canola using a low temperature pyrolysis method. After incubation of three acid soils, pH buffering capacity was then determined.
Results and discussion
pH buffering capacity had a range of 9.1–32.1 mmol kg–1 pH–1 for 18 acid soils from tropical and subtropical regions of China. The pH buffering capacity was highly correlated (R 2 = 0.707) with soil cation exchange capacity (CEC) measured with ammonium acetate method at pH 7.0 and decreased with soil evolution due to the decreased CEC. Incorporation of biochars at rates equivalent to 72 and 120 t ha−1 increased soil pH buffering capacity due to the CEC contained in the biochars. Incorporation of peanut straw char which itself contained more CEC and alkalinity induced more increase in soil CEC, and thus greater increase in pH buffering capacity compared with canola straw char. At 5% of peanut straw char added, soil CEC increased by 80.2%, 51.3%, and 82.8% for Ultisol from Liuzhou, Oxisol from Chengmai and Ultisol from Kunlun, respectively, and by 19.8%, 19.6%, and 32.8% with 5% of canola straw char added, respectively; and correspondingly for these soils, the pH buffering capacity increased by 73.6%, 92.0%, and 123.2% with peanut straw char added; and by 31.3%, 25.6%, and 52.3% with canola straw char added, respectively. Protonation/deprotonation of oxygen-containing functional groups of biochars was the main mechanism for the increase of pH buffering capacity of acid soils with the incorporation of biochars.
CEC was a key factor determining pH buffering capacity of acid soils from tropical and subtropical regions of China. Decreased CEC and content of 2:1-type clay minerals during evolution of tropical soils led to decreased pH buffering capacity. Incorporation of biochars generated from crop straws did not only ameliorate soil acidity, but also increased soil pH buffering capacity.
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Aitken RL (1992) Relationships between extractable Al, selected soil properties, pH buffer capacity and lime requirement in some acidic Queensland soils. Aust J Soil Res 30:119–130
Aitken RL, Moody PW (1994) The effect of valence and ionic strength on the measurement of pH buffer capacity. Aust J Soil Res 32:975–984
Aitken RL, Moody PW, McKinley PG (1990) Lime requirement of acidic Queensland soils. I. Relationships between soil properties and pH buffer capacity. Aust J Soil Res 28:695–701
Bloom PR (2000) Soil pH and pH buffering. In: Sumner ME (ed) Handbook of soil science. CRC, Boca Raton, pp B333–B352
Boehm HP (2002) Surface oxides on carbon and their analysis: a critical assessment. Carbon 40:145–149
Chan KY, van Zwieten L, Meszaros I, Downie A, Joseph S (2007) Agronomic values of greenwaste biochar as a soil amendment. Aust J Soil Res 45:629–634
Chan KY, van Zwieten L, Meszaros I, Downie A, Joseph S (2008) Using poultry litter biochars as soil amendments. Aust J Soil Res 46:437–444
Chun Y, Sheng GY, Chiou CT, Xing BS (2004) Compositions and sorptive properties of crop residue-derived chars. Environ Sci Technol 38:4649–4655
Cross A, Sohi SP (2011) The priming potential of biochar products in relation to labile carbon contents and soil organic matter status. Soil Biol Biochem 43:2127–2134
Dolling PJ (1995) Effect of lupins and location on soil acidification rates. Aust J Exp Agr 35:753–763
Gaskin JW, Steiner C, Harris K, Das KC, Bibens B (2008) Effect of low-temperature pyrolysis conditions on biochar for agricultural use. TASABE 51:2061–2069
Guo JH, Liu XJ, Zhang Y, Shen JL, Han WX, Zhang WF, Christie P, Goulding KWT, Vitousek PM, Zhang FS (2010) Significant acidification in major Chinese croplands. Science 327:1008–1010
Helyar KR, Cregan PD, Godyn DL (1990) Soil acidity in New South Wales—current pH values and estimates of acidification rates. Aust J Soil Res 28:523–537
Herre A, Lang F, Siebe CH, Dohrmann R, Kaupenjohann M (2007) Mechanisms of acid buffering and formation of secondary minerals in vitric Andosols. Europ J Soil Sci 58:431–444
Jiang J, Xu RK, Zhao AZ (2011) Surface chemical properties and pedogenesis of tropical soils derived from basalts with different ages in Hainan, China. Catena 87:334–340
Koide RT, Petprakob K, Peoples M (2011) Quantitative analysis of biochar in field soil. Soil Biol Biochem 43:1563–1568
Magdoff FR, Bartlett RJ (1985) Soil pH buffering revisited. Soil Sci Soc Am J 49:145–148
Moody PW, Aitken RL (1997) Soil acidification under some tropical agricultural systems. I. Rates of acidification and contributing factors. Aust J Soil Res 35:163–173
Nelson PN, Su N (2010) Soil pH buffering capacity: a descriptive function and its application to some acidic tropical soils. Aust J Soil Res 48:210–207
Noble AD, Cannon M, Muller D (1997) Evidence of accelerated soil acidification under Stylosanthes dominated pastures. Aust J Soil Res 35:1309–1322
Pansu M, Gautheyrou J (2006) Handbook of soil analysis—mineralogical, organic and inorganic methods. Springer, Heidelberg
Prendergast-Miller MT, Duvall M, Sohi SP (2011) Localisation of nitrate in the rhizosphere of biochar-amended soils. Soil Biol Biochem 43:2243–2246
Sohi SP, Krull E, Lopez-Capel E, Bol R (2010) A review of biochar and its use and function in soil. Adv Agron 105:47–82
Ulrich B (1986) Natural and anthropogenic component of soil acidification. Z Pflanzenernähr Bodenk 149:702–717
Wang H, Xu RK, Wang N, Li XH (2010) Soil acidification of Alfisols as influenced by tea plantation in eastern China. Pedosphere 20:799–806
Weaver AR, Kissel DE, Chen F, West T, Adkins W, Rickman D, Luvall JC (2004) Mapping soil pH buffering capacity of selected fields in the coastal plain. Soil Sci Soc Am J 68:662–668
Xu RK, Coventry DR, Farhoodi A, Schultz JE (2002) Soil acidification as influenced by crop rotations, stubble management and application of nitrogenous fertiliser, Tarlee, South Australia. Aust J Soil Res 40:483–496
Yuan JH, Xu RK (2011) The amelioration effects of low temperature biochar generated from nine crop residues on an acidic Ultisol. Soil Use Manage 27:110–115
Yuan JH, Xu RK, Zhang H (2011a) The forms of alkalis in the biochar produced from crop residues at different temperatures. Bioresour Technol 102:3488–3497
Yuan JH, Xu RK, Qian W, Wang RH (2011b) Comparison of the ameliorating effects on an acidic ultisol between four crop straws and their biochars. J Soils Sediment 11:741–750
Zhang HM, Wang BR, Xu MG (2008) Effects of inorganic fertilizer inputs on grain yields and soil properties in a long-term wheat-corn cropping system in south China. Commun Soil Sci Plant Anal 39:1583–1599
The study was supported by the National Natural Science Foundation of China (40971135) and the Knowledge Innovation Program Foundation of the Chinese Academy of Sciences (KZCX2-YW-438). The suggestions received from two anonymous reviewers during the review stage of this manuscript were greatly appreciated.
Responsible editor: Caixian Tang
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Xu, Rk., Zhao, Az., Yuan, Jh. et al. pH buffering capacity of acid soils from tropical and subtropical regions of China as influenced by incorporation of crop straw biochars. J Soils Sediments 12, 494–502 (2012). https://doi.org/10.1007/s11368-012-0483-3
- Acid soil
- pH buffering capacity
- Tropical and subtropical regions