马尾松林冠下套种阔叶树20年间土壤肥力变化

目的探讨马尾松公益林林相改造后土壤肥力的变化,以便为马尾松公益林经营提供依据。方法在马尾松公益林中采用间伐后套种细柄阿丁枫、木荷、闽楠的林相改造试验,把马尾松纯林改造培育为异龄复层的针阔混交林,并在改造当年、改造后5年、改造后10年、改造后20年对4种林分的土壤理化性质进行测定。结果4种林分土壤的水稳性团聚体组成、土壤孔隙、土壤的有机质及养分含量均随着时间的推移呈增加的趋势,并且这种趋势随时间的进展而加大,增加的量表现为马尾松细柄阿丁枫混交林>马尾松木荷混交林>马尾松闽楠混交林>马尾松纯林,前3种林分相差较小,但前3种林分与马尾松纯林间的差异显著。马尾松纯林套种阔叶树林相改造后20年(2016年)与套种当年(1996年)相比,马尾松细柄阿丁枫混交林、马尾松木荷混交林、马尾松闽楠混交林、马尾松纯林林地土壤0~20cm层土壤,干土>0.25mm水稳性团聚体分别增加了5.21%、4.67%、3.78%、1.24%,土壤总孔隙度分别增加了3.82%、3.78%、3.01%、0.49%,土壤有机质分别增加了9.67、8.39、7.26、2.84g/kg,土壤全N含量分别增加了0.22、0.13、0.14、0.05g/kg,土壤全P分别增加了0.10、0.06、0.05、0.04g/kg。结论马尾松公益林套种阔叶树林相改造后形成的混交林具有较好的培肥土壤功能,有利于公益林的地力维持和持续经营。 

Changes in soil fertility after interplanting pure Pinus massioniana plantations with broadleaved forest under the canopy during 20 years

ObjectiveLong maintenance of soil fertility is an important research content of sustainable forest management in plantation.MethodThis article aims to explore the soil fertility changes on the treatment stands after Pinus massoniana pure forest transferred into uneven-aged conifer-hardwood mixed forest by thinning and then interplanting with Altingia gralilipes, Schima superba, Phoebe bournei, respectively. The soil physical and chemical properties of four treatments were determined after forest interplanting with broadleaved tree species at the 1st, 5th, 10th and 20th years.ResultThe soil aggregate composition, soil pore, soil organic matter and soil nutrient content of the four treatments of forest soil all showed increasing trend with time, and this trend increased as time went on. The order of the increased amount of soil characteristics showed as Pinus massoniana × Altingia gralilipes (MPA)> Pinus massoniana × Phoebe bournei (MPP)> Pinus massoniana × Schima superba (MPS)> pure Pinus massoniana (PP). The differences in soil characteristics among the first three mixed stands were small, but the differences between the first three mixed forest and pure Pinus massoniana stands were significant. Compared the soil characteristics of the transformation forest between the first year and the 20th year, it was found that, in 0-2cm soil of MPA, MPP, MPS and PP forest, the water stability aggregates of dry soil diameter >0.25mm increased by 5.21%, 4.67%, 3.78%, 1.24%, the total soil porosity increased by 3.82%, 3.78%, 3.01%, and 0.49%, soil organic matter increased by 9.67, 8.39, 7.26, 2.84g/kg, soil total nitrogen (N) content increased by 0.22, 0.13, 0.14, 0.05g/kg, and soil total phosphorus(P) increased by 0.10, 0.06, 0.05, 0.04g/kg, respectively.ConclusionThe transformation forest of Pinus massoniana intercropping with broadleaved tree species has good function in fertilizing soil, and is conducive to the maintenance and sustainable management of the public welfare forest.