淋溶条件下马尾松针对土壤的酸化作用  

Soil acidification induced by pinus massoniana needles under leaching conditions

作　　者：杨平平[1,2] 徐仁扣[1] 黎星辉[2] 

机构地区：[1]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,江苏南京210008 [2]南京农业大学茶叶科学研究所,江苏南京2100095

出　　处：《生态环境学报》2012年第11期1817-1821,共5页Ecology and Environmental Sciences

基　　金：中国科学院知识创新工程重要方向性项目(KZCX2-YW-438)

摘　　要：亚热带地区广泛种植马尾松(Pinus massoniana)会导致林地土壤酸化和贫瘠化,但相关机制还不清楚。通过室内土柱淋溶实验,研究了添加马尾松针对土壤酸度及盐基阳离子迁移、淋出的影响。结果表明,淋溶过程中淋出液pH随淋溶次数的增加而逐渐增加。淋溶实验后期,添加马尾松针处理淋出液pH高于对照处理。淋出液电导率随淋溶次数增加而下降,前期下降很快,后期下降缓慢。整个淋溶实验期间,添加马尾松针处理淋出液电导高于对照处理,淋出液中盐基阳离子的累积量也高于对照处理,与电导率的变化趋势一致。4种盐基阳离子淋失量由大到小的顺序为Ca2+,Mg2+,Na+,K+。间歇淋溶24周后,初始pH为7.68的荒地土壤各土层由表及里pH比对照分别下降了1.74、0.82和0.40,初始pH为5.61的茶园土壤pH分别下降了0.40、0.11和0.17。虽然添加马尾松针向土壤中归还了大量盐基阳离子,但淋溶实验结束时,添加马尾松处理土壤中盐基阳离子含量多低于对照。实验结果表明,间歇淋溶条件下,马尾松针覆盖会加速土壤酸化,特别对初始pH相对较高的土壤,酸化作用更加明显。It is well known that planting pinus massoniana extensively in subtropical regions caused soil acidification and infertility, but the mechanisms of this effect has not been known. In this paper, influence of addition of pinus massoniana needles on soil acidification and leaching loss of base cations was investigated with leaching experiment on soil column. The results indicated that the leachate pH value increased with the increase in leaching times and was higher for the treatments with pinus massoniana needles added than for the control at the later stage of leaching experiment. The electric conductivity of leachates decreased sharply with the increase in leaching times at the ea（ly stage of leaching experiment and then slowly at the later stage, and was higher for the treatments with pinus massoniana needles added than for the control during the leaching experiment. The same trends were observed for cumulative amounts of base cations Ca2＋, Mg2＋, K＋, and Na＋ in leachates. The leaching loss of 4 base cations followed the order： Ca2＋ 〉 Mg2＋ 〉 Na＋ 〉 K＋. It can be concluded that the addition of pinus massoniana needles accelerated soil acidification, especially for the soil from uncultivated land with high initial pH value of 7.68. After 24 weeks of leaching, the soil pH for surface, subsurface and bottom layers were decreased by 1.74, 0.82 and 0.40 units, respectively, compared with the control without pinus massoniana needles added. Correspondingly, the pH of soil from tea garden with initial pH value of 5.61 were decreased by 0.40, 0.11 and 0.17 units. The addition of pinus massoniana needles also enhanced the migration of base cations from surface to bottom layers, even leaching out from soil column.

关 键 词：马尾松 土壤酸化 盐基离子 土壤PH 

分 类 号：S153[农业科学—土壤学]