植物残体分解液淋洗对土柱 Ca2+ 淋失量的影响

选取紫花苜蓿、羊草、冷蒿3种北方草原代表性的草本植物,通过土柱淋洗试验,研究植物残体分解液淋洗对土壤溶液Ca2+ 含量的影响.结果表明,不同的植物残体种类和分解期对淋洗后土柱中溶液相Ca2+ 总量的影响不同,其中羊草初期分解液导致的降低量最大,促进土壤碳酸盐的溶解,而紫花苜蓿初期分解液的降低量最小,有利于土壤碳酸盐的稳定.因此,植被自然更替(草场退化)或人为更替(退耕还草)时会影响到土壤溶液中Ca2+ 的浓度,进而影响土壤中碳酸盐的沉淀-溶解平衡,最终导致土壤无机C库的增减.

Effects of Plant Debris Leachates on Ca2+ Leaching from Soil Column

The effects of plant debris decomposition leachates of alfalfa, leymus and artemisia, representative plants of North China grassland, on Ca2+ concentration were studied by soil column experiment. Results showed that gross Ca2+ loss was dependent on plant debris type and decomposition period. Ca2+ lost most in soil column leached by earlier decomposition leachate of leymus debris, meaning more dissolution of soil CaCO3 in the column. Whereas the dissolution was the least in soil column leached with earlier decomposition solution of alfalfa. These results indicated that Ca2+ concentration in soils will change under vegetation alteration naturally or artificially. In this case, CaCO3 precipitation/dissolution process could be impacted and the balance of soil inorganic carbon pool would change accordingly.