冻融干湿循环条件下粒径及盐分对土壤粗颗粒风化速率的影响

Impact of particle size and soil salinity on weathering of mineral particles under freeze-thaw and drying-wetting cycles

【目的】探究冻融干湿循环条件下,土壤粒径及盐分对土壤粗颗粒风化速率的影响。【方法】以土壤粗颗粒(灰绿板岩)为研究对象,设置粒径(10、20、30mm)、盐分浓度(3、6、10g/L及蒸馏水作对照)两因素,开展冻融干湿循环随机试验,分析不同循环次数下土壤粗颗粒风化速率的变化规律。【结果】(1)在水盐溶液处理下土壤粗颗粒风化速率均比单纯水处理大,10g/L盐分处理下的土壤粗颗粒风化速率大于其他处理。在20~60次冻融干湿循环之间,10 mm土壤粗颗粒的风化速率随盐分浓度的增加而增大。(2)土壤粗颗粒风化速率随粒径的增大呈减小趋势,且10 mm的土壤粗颗粒风化速率大约是30 mm的2倍。(3)土壤粗颗粒风化速率随冻融干湿循环次数的增大而增大,A1B4(10 mm 10 g/L)组合下的土壤粗颗粒风化速率最大。【结论】在冻融干湿循环影响下,小粒径的土壤粗颗粒风化速率大于大粒径,且水盐作用对土壤粗颗粒风化速率的影响大于单纯水作用。

[Objective]Freezing-thawing and drying-wetting cycles are important abiotic processes in mineral particle weathering and their effect is modulated by many other processes.In this paper,we investigate the impact of partcle size and soil salinity on mineral particle weathering.[Method]Green slate particles were used.The expeniment consisted of three particle size teatments:10,20 and 30 mm,and three soil salimity teatments with salt concentration of the soil water being 3,6 and 10 g/L,respectively.Each treatment was subjected to randomized feeze-thaw and drying-wetting cycles.Duing the experiment,we measured the weathering rate of all particles.[Result]①Soil salinity increased particle weathering rate,but the increase depended on soil water concentration.In the treatments we compared,soil water concentation of 10 g/L gave the best results.For the10 mm particles,their weathering rate increased with soil salinity when they were subjected to 20 and 60 feeze thaw and drying-wetting cycles.②The weathering rate decreased with particle size,with the weathering rate of the 10 mm particles being two times that of the 30 mm particles.③The weathering rate increased with the number of feeze-thaw drying-wetting cycles.[Conclusion]Under the influence of freeze fthaw and duying-wetting cycles,the weathering rate of small particles is higher than that of large particle.Soil salinity also increased the weathering rate,albeit the increasing rate depended on soil water concentration.