Aluminum species in soil solution and their formation conditions.

为了研究酸性土壤中铝对植物的毒害特性及其浓度，对农田和森林土壤中提取的土壤溶液进行了检测。采用Adams(1971)提出的逐次逼近法计算了Al的形态及其浓度。在本文中，我们通过下面的质量平衡方程计算了Al物种，假设在几个使用铝盐溶液的研究中强烈建议的四种多核Al物种可以共存。Alt(总Al)=[Al^&lt；3+&gt；]+[AlOH^&lt；2+&gt；]+[Al(OH)_2^+]+[Al(OH)_3^o]+[AlSO_4^+]+[AlHPO_4^+]+[AlH_2PO_4^&lt；2+&gt；]+2[Al_2(OH)_2^&lt；4+&gt；]+3[Al_3(OH)_4^&lt；5+&gt；]+13[Al_&lt；13&gt；(OH)_&lt；24&gt；^&lt；7+&gt；]+6[Al_6(OH)_&lt；15&gt；^&lt；3+&gt；]The结果表明：1)土壤溶液的pH值在4.73.0的最大酸性范围内，PALT值在4.52.3时，Al~(2+)和Gt~(3+)；如果土壤溶液的pH值在…范围内，则成为Alt中的主要Al物种多核物种Al6(OH)&lt；15&gt；3)当土壤溶液的pH值为7.3~5.3，PALT为7.5~4.5时，Al(OH)_3^O成为Alt中的优势铝物种；4)在pH值为7.31~3.0，PALT为7.31~2.3的范围内，Al_2(OH)_2^&lt；4+&gt；Al_3(OH)_4^&lt；5+&gt；成为主要的Al物种，这些物种的浓度比Alt浓度低百分之一。结果表明，在Alt浓度大于10；-2&gt；Moll；-lt；-1&gt；pH值在5~6.5范围内的铝盐溶液中，这些多核物种可以成为主要的Al物种。6)如果土壤溶液的pH值在6.5~5之间，Palt值在7~4之间，而Palt值几乎等于pH值，则Al(OH)_2^+在Alt中占几十个百分比。Al(OH)_2^+、Al(OH)_3^o、Al_6(OH)_3^o、Al_6(OH)_3~+、Al_6(OH)_3~+和AlHPO_4~+是Alt中主要的Al物种。较少

In order to examine characteristics of aluminum species toxic to plants and their concentrations in acid soils, soil solution extracted from soils of crop fields and forests was examined. Al species and their concentrations were calculated by applying the method of successive approximation reported by Adams (1971). In the present paper, we calculated Al species through the following mass balance equation, assuming that four kinds of polynuclear Al species which have been strongly suggested in several studies using aluminum salt solution can coexist.Alt (total Al) =[Al^<3+>]+[AlOH^<2+>]+[Al(OH)_2^+]+[Al(OH)_3^o]+[AlSO_4^+]+[AlHPO_4^+]+[AlH_2PO_4^<2+>]+2[Al_2(OH)_2^<4+>]+3[Al_3(OH)_4^<5+>]+13[Al_<13>(OH)_<24>^<7+>]+6[Al_6(OH)_<15>^<3+>]The following results were obtained.1) If the pH value of soil solution pH is in the most acid range of 4.7 through 3.0 and the pAlt value ranges from 4.5 through 2.3, Al^<3+> became dominant Al species in Alt.2) If the pH value of soil solution ranges fro … More m 7.3 to 5.3 and the pAlt value ranges from 5 to 2.3, then polynuclear species, Al_6(OH)_<15>^<3+>, becomes dominant Al species in Alt.3) If the pH value of soil solution ranges from 7.3 to 5.3 and the pAlt value ranges from 7.5 to 4.5, then Al(OH)_3^o becomes dominant Al species in Alt.4) In the pH value of range from 7.31 through 3.0 and in the pAlt value range from 7.31 through 2.3, neither Al_2(OH)_2^<4+> nor Al_3(OH)_4^<5+> becomes dominant Al species and the concentration of these species was one hundredth less than the Alt concentration. It is inferred that these polynuclear species can become dominant Al species in alminum salt solution where Alt concentration is larger than 10^<-2> molL^<-1> and the pH value ranges from 5 to 6.5) The ratio of Al_<13>O_4(OH)_<24>^<7+> concentration to Alt concentration is about one to hundred million, and thus the existence can be ignored.6) If the pH value of soil solution ranges from 6.5 through 5 and the pAlt value ranges from 7 through 4 and the pAlt value is almost equal to the pH value, then Al(OH)_2^+ species amounts to dozens of percentages in Alt.7) In the case of cultivated field soils amended by high amounts of phosphate fertilizers, AlHPO_4^+ is recognized as dominant Al species.Based on these results, it is assumed that one of Al^<3+>, Al(OH)_2^+, Al(OH)_3^o, Al_6(OH)_<15>^<3+>, and AlHPO_4^+ becomes dominant Al species in Alt in the pH and pAlt ranges examined. Less