摘要
酸雨中的SO24-和NO3-等阴离子在土壤中迁移时会引起大量的盐基离子淋溶,导致土壤退化。用室内土柱模拟SO24-和NO3-在红壤旱地各土层中的垂直穿透状况,并用Hydrus-1D模型对试验结果进行了拟合和预测。结果表明,NO3-在红壤各层中的穿透速度较快,其中在耕作层的穿透曲线峰值最高,C/C0达到0.39,峰值高低顺序依次为:耕作层>母质层>淋溶层>犁底层。SO24-在土柱中的穿透速度远低于NO3-,穿透曲线有明显的拖尾现象。其在各土层的穿透时间依次为:母质层>犁底层>淋溶层>耕作层;而其峰值高低顺序依次为:耕作层>淋溶层>母质层>犁底层,最高点耕作层的顶点C/C0仅为0.22。用Hydrus-1D模型对试验结果进行模拟,所得的SO24-和NO3-穿透土壤的浓度模拟值与其实测值均呈极显著的正相关关系。利用数学模拟获得了饱和导水率和垂直扩散率等溶质运移参数,并预测了研究区酸雨后SO24-和NO3-在红壤耕层的迁移状况,表明SO24-会在酸雨结束后持续淋溶,从而影响土壤中Ca、Mg等盐基离子的淋失。
Acid rain is a global menace from agricultural, environmental and ecological perspective. SO4^2- and NO; are major anions in acid rain which can speed up soil acidification and result in leaching losses of the basic cations. In this study, some soil columns were used to describe the break through curves （BTCs）of infiltration of SO4^2- and NO; in typical red soils. The breakthrough velocity of SO4^2- was lower than that of NO3^- A remarkable difference in BTCs of NO3^- was observed in different soil layers. The peak value of BTCs in plough layer, having C/Co value 0.39, was the highest in soil profiles. Order of the peak value of BTCs was plough layer〉 parent material layer 〉leached layer〉 plow pan layer. Track of BTCs of SO4^2- was prolonged obviously in each layer. The peak value of BTCs （0.22）in plough layer was higher than other layers. Hydrus-1D model was used to simulate the penetrative process. Correlative coefficients of BTCs and its simulation value were higher than 0.9. So, Hydrus-1D model proved to be a useful tool to estimate the penetrative process of SO4^2- and NO; in red soil region. The infiltration of SO4^2- and NO; was predicted by this model after an acid rain fall in rainy season. It is concluded that a sustained infiltration of SO2^4- could result in leaching losses of the basic cations.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2009年第1期107-111,共5页
Journal of Agro-Environment Science
基金
国家重点基础研究发展计划(973计划)(2005CB121103)
中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室开放课题(0751010015)
