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在干旱/半干旱地区,土壤干湿交替现象非常明显.在全球气候变化背景下,预测未来科尔沁沙地的土壤干湿交替变化强度将进一步加剧.本研究采用室内原位土柱培养方法,模拟干湿交替对科尔沁沙地小叶杨和樟子松叶凋落物分解速率及养分释放的影响.试验设置3个处理:恒湿处理(CM)、轻度干湿交替处理(DW_1,10 d干燥+20 d湿润)和重度干湿交替处理(DW_2,20 d干燥+10 d湿润).整个培养试验共处理180 d,其中进行4次干湿交替循环处理,并在干湿交替处理结束后,将各处理置于相同土壤水分条件(60%田间持水量)延时培养60 d.结果表明:小叶杨和樟子松叶凋落物分解及养分释放对干湿交替的响应一致.在干湿交替期间,DW_2处理显著抑制叶凋落物分解及叶凋落物C、木质素和总酚释放;与CM相比,DW_2处理叶凋落物质量、C、木质素和总酚残留率分别增加17.4%、23.8%、35.2%和32.7%,而干湿交替对叶凋落物N和P养分释放无显著影响.干湿交替处理结束和延时培养结束时,不同干湿处理叶凋落物分解及养分残留率的变化具有一致性.而延时培养期间DW_2处理凋落物分解速率、叶凋落物C和木质素释放加快,表明干湿交替对叶凋落物分解及养分释放具有短期延时效应.
In arid / semi-arid areas, the phenomenon of alternation of wet and dry soil is very obvious.Under the background of global climate change, it is predicted that the intensity of alternate dry-wet alternation will be further aggravated in Horqin sandy land.In this study, Effect of alternate wetting and drying on litterfall decomposition rate and nutrient release of Populus simonii and Pinus sylvestris var. Mongolica in Horqin sandy land. Three treatments were set up: constant humidity treatment (CM), mild dry-wet alternation treatment (DW_1, Wetting) and severe wetting and drying (DW_2, drying for 20 d and wetting for 10 days) .The whole culture experiment co-treated for 180 days, of which 4 cycles of alternating wet and dry cycles were carried out, and after alternating wet and dry treatments, The results showed that litter decomposition and nutrient release of Populus simonii and Pinus sylvestris var.mongolica had the same response to alternate wetting and drying.During the wet-dry alternation period, DW_2 treatment was significantly Leaf litter decomposition and leaf litter C, lignin and total phenols were inhibited. Compared with CM, leaf litter quality, C, lignin and total phenolic content of leaves increased by 17.4%, 23.8%, 35.2% and 32.7%, while alternating wet and dry pairs Leaf litter N and P nutrient release had no significant effect.While the wet-dry alternation treatment and delayed incubation at the end of different dry and wet leaf litter decomposition and nutrient residual rate changes are consistent. The rate of decomposition, leaf litter C and lignin release accelerated, indicating that the alternate wetting and drying had the short-term delay effect on leaf litter decomposition and nutrient release.