樟子松固沙林土壤碳截存及土壤呼吸对干湿变化的响应

 在科尔沁沙地测定分析了流动沙丘栽植樟子松林23 a后的土壤碳截存作用,以及林地和流动沙丘土壤呼吸对干湿变化的响应。结果表明:①流动沙丘造林后土壤容重减小,土壤颗粒中极细沙和黏粉粒含量显著增加;②樟子松林地0~5 cm和5~15 cm层土壤有机碳截存量分别为221.8 g·m-2和113.9 g·m-2,截存速率分别为9.64 g·m-2·a-1和4.95 g·m-2·a-1;CaCO3-C截存量分别为4.0 g·m-2和2.5 g·m-2, 截存速率分别为0.17 g·m-2·a-1和0.11 g·m-2·a-1;③干旱条件下土壤呼吸随气温的升高呈现指数减小;无论是干旱还是降雨后,林地土壤呼吸速率均显著高于流动沙丘;④降雨刺激后土壤呼吸显著增加,林地增加的幅度显著高于流动沙丘;林地地表凋落物去除后土壤呼吸速率下降,并且在降雨后下降更为明显。

Soil Carbon Sequestration in Sand-fixation Plantation of Pinus sylvestris var.Mongolica and Response of Soil Respiration to Drought and Wet Conditions

Soil carbon sequestration of sand-fixation plantation and the response of soil respiration to different water condition in Pinus sylvestris var. Mongolica woodland and mobile sand dune were investigated in Horqin Sandy Land. Results show that (1) after 23 years since Pinus sylvestris var. Mongolica was planted in mobile sand dune, the content of very fine sand and silt+clay increased significantly in soil, whereas soil bulk density decreased; (2) the soil organic carbon sequestration in woodland was 221.8 g·m-2and 113.9 g·m-2 at the depth of 0~5 cm and 5~15 cm, respectively, and the sequestration rate was 9.64 g·m-2 and 4.95 g·m-2·a-1, respectively; the CaCO3-C sequestration was 4.0 g·m-2 and 2.5 g·m-2 and the rate was 0.17 g·m-2 and 0.11 g·m-2·a-1, respectively; (3) during drought period, soil respiration showed a strong negative exponential relationship with air temperature; soil respiration in woodland was higher than that in mobile sand dune whether the condition is drought or not; and (4) soil respiration increased after rain process, but the increment was higher in woodland; the removal of surface litter resulted in decrease of soil respiration and rain exacerbated the difference.