富里酸对红壤酸度的改良及酸化阻控效果

用采自安徽由第四纪红色黏土发育的红壤(红黏土)和采自江西由第三纪红砂岩发育的红壤(红砂土)进行室内培养试验,研究了添加富里酸对红壤酸度的改良效果和红壤酸化的阻控效果。结果表明,添加富里酸显著提高了两种土壤的pH,并且随着富里酸添加量的增加对土壤pH的提升效果逐渐增加,添加50g/kg富里酸处理红黏土和红砂土的土壤pH分别由对照的4.31和4.69提高至5.91和5.97。添加富里酸也提高了两种土壤的pH缓冲容量(pHBC),因而提高了土壤的抗酸化能力。与土壤pH的变化趋势相似,富里酸对土壤pHBC的提升效果也随其加入量的增加而增加。添加50 g/kg富里酸时,红黏土和红砂土的pHBC分别由对照的20.73和7.78 mmol/(kg×pH)提高至35.31和23.30 mmol/(kg×pH),分别比对照提高了0.70倍和1.99倍。添加富里酸不仅可以有效改良红壤酸度,还可以提高红壤的抗酸化能力。富里酸对红砂土酸化的阻控效果明显优于对红黏土。

Effect of Fulvic Acid on Ameliorating Soil Acidity and pH Buffering Capacity of Two Ultisols

A clay red soil from Anhui and a sandy red soil from Jiangxi were collected for laboratory incubation experiment to study the effects of applying fulvic acid on ameliorating soil acidity and soil pH buffering capacity. Results showed that applying fulvic acid increased soil pH, and the ameliorating effect increased with the amount of fulvic acid added. Adding 50 g/kg fulvic acid increased soil pH from 4.31 to 5.91 for clay red soil and from 4.97 to 5.97 for sandy red soil, respectively. Moreover, similar to change in soil pH, applying fulvic acid increased soil pH buffering capacity (pHBC), and the more fulvic acid added led to greater increase in soil pHBC. Adding 50 g/kg fulvic acid increased soil pHBC from 20.73 to 35.31 mmol/(kg?pH) for clay red soil and from 7.78 to 23.30 mmol/(kg?pH) for sandy red soil, respectively. In conclusion, applying fulvic acid can not only ameliorate effetively soil acidity of two red soils, but also increase soil pHBC and thus increase soil resistance to acidification, and the effect is better for sandy red soil than for clay red soil.