【摘要】 以太湖地区典型水稻土——水耕铁渗人为土为供试材料,通过添加CaCO3和H2SO4培养及滴定的方法,研究不同pH降雨和施氮对土壤酸碱缓冲体系的影响。结果显示,土壤在添加CaCO3和H2SO4培养后进行不同量酸碱滴定,土壤在pH 4.0~7.5的突跃范围内与酸碱加入量呈显著的线性相关,表明该测定方法对供试土壤适用。同时施氮和降雨对土壤的酸化都有加速作用,各处理0-40 cm层土壤酸碱缓冲容量为1.91~2.20 cmol/kg,增加施氮量、降低降雨pH都降低土壤的酸碱缓冲容量,且土壤酸碱缓冲容量与盐基淋出量呈显著负相关关系,但不同酸度降雨对土壤酸度变化及酸碱缓冲容量变化影响主要为0-20 cm层,而对20-40 cm层影响较小;而施氮除影响土壤pH及酸碱缓冲容量的0-20 cm层外,还影响到20-40 cm层。表明研究土壤处在以盐基离子为主的酸碱缓冲体系,在此体系下,施氮或氮沉降对土体的影响比酸沉降更为深入。更多还原

【Abstract】 CaCO3 and H2SO4 amendment and titration method to study the soil acidification buffer capacities under different pH 2.5,4.5,6.5 precipitations combined with nitrogen rates with 0,150,300 mg/kg,respectively,in hydromorphic paddy soil.Results showed that soil exerting silicate and base cations primary buffering system,and the relationship between the CaCO3 and H2SO4 amendment rates and soil pH for treatment with different pH rainfall and nitrogen rates were all significant and had high linear regression correlation coefficients,indicating CaCO3 and H2SO4 amendment and titration method could be used for estimating buffer capacities of tested soils and south acid soils.The soil buffer capacity ranged from 1.91 cmol/kg to 2.20 cmol/kg,and decreased with more N rates and lower pH precipitations,moreover,a linear correlation between the soils buffer capacities and the cations leaching rates was found for all soils treated under different pH precipitation and nitrogen rates,indicating that the cations played an important role in soils buffer system,and pH and soil buffer capacities changes occurred mainly in 0-20 cm layer under different pH precipitation,for the nitrogen application 20-40 cm changed occurred as well as the 0-20 cm layer,indicating that the nitrogen input got a more effect on the soil layer than that of acid precipitation.更多还原