原始红松林皆伐后穿透雨对凋落物淋溶过程的影响

[目的]揭示原始红松林皆伐恢复演替为60年生的次生阔叶林后,凋落物对淋溶过程土壤养分归还及酸沉降的缓冲作用的影响,为评价森林生态功能的变化提供参考.[方法]以小兴安岭地区典型的原始红松林和皆伐后恢复演替60 a的次生阔叶林为研究对象,在两个样地内选择非林隙且林木通直分布均匀处放置30个体积为1 L的冠层穿透雨收集器,在...

Effects of the litter leaching process by throughfall after clear cutting of primary Pinus koraiensis forest

【Objective】The effects of the throughfall leaching process on the litter nutrient release into soil nutrition and the buffer action of litter on throughfall-accompanied acid deposition were assessed in a primary Pinus koraiensis forest and in a secondary broad-leaved forest that had recovered for 60 years after clear-cutting.【Method】We selected a typical primary P.koraiensis forest and a 60-year-succession secondary broad-leaved forest after clear cutting of the primary forest in Lesser Khingan Mountains as the research materials.Two sampling sites were set and 30 throughfall collectors with a volume of 1 L were placed in the two sites with nonforest gaps and the uniform straight tree distribution.A litter leaching solution collector was set up near each throughfall collector.We collected in situ the solution of throughfall and litter leaching in the two forests at an interval of 45 days from April to November 2017.The concentrations of nutrient elements and dissolved organic matter(DOM),and pH values in the litter leaching solution of the two forest types were compared.【Result】Compared to the primary P.koraiensis forest,the total amount of leaching nutrient elements in the secondary broad-leaved forest was significantly lower(P<0.05).The changing patterns of leached elements were inconsistent between the two forests.The release peak of nutrient elements of the two forest types both occurred mainly in June and July.The total amounts of DOM,dissolved organic carbon(DOC)and dissolved organic phosphorus(DOP)leached from the litters were significantly higher,but the total dissolved organic nitrogen(DON)was lower in the primary P.koraiensis forest than in the secondary broad-leaved forest(P<0.01).The changing patterns of the nutrient elements and DOM in the throughfall and litter leaching solutions were similar between the two forest types.The pH value of the throughfall ranged from 5.34 to 7.21,while the pH value of leachate in the litter ranged from 6.37 to 7.65.The results indicated that the litter layer effectively regulated the pH of the throughfall.The range of pH regulation by the litter layers was larger in the primary P.koraiensis forest than that in the secondary broad-leaved forest.【Conclusion】The litter layers play regulatory roles in solution pH before the throughfall into forest soils.Compared to the primary P.koraiensis forest,the nutrient release efficiency and pH adjustment of the litter layers were lower in the secondary broad-leaved forest.