长白落叶松纯林改造对林地土壤性质的影响

Effects of pure Larix olgensis plantation improvement on the soil properties

以黑龙江省林口林业局长白落叶松纯林带状伐后栽植阔叶树种形成的针阔混交林为对象,研究水曲柳、长白落叶松—水曲柳、长白落叶松、长白落叶松—胡桃楸与胡桃楸等5种林带下土壤的物理性质、养分状况和微生物数量。结果表明：长白落叶松纯林改造成针阔叶混交林初期,土壤密度随土层深度增加而显著增加,土壤孔隙度则随土层深度增加而显著降低,林带间差异不显著;各林带有机质含量、养分元素全量及速效养分含量均随土层加深而显著减少,但全K含量变化不明显,阔叶林带及针阔林带土壤养分含量多高于落叶松林带,0-10 cm土层的全N、全P与全K含量最大分别提高13.99%、8.00%与11.23%,水解N、有效P与速效K含量最大分别提高18.84%、12.37%与6.71%;土壤细菌、真菌与放线菌主要集中在0-20 cm土层,且随土层深度增加而减少,阔叶林带及针阔林带土壤微生物总量均高于落叶松林带,大小顺序为水带〉落-水带〉落-胡带〉胡带〉落带。研究结果可为长白落叶松纯林改造提供科学依据。

Physical properties,nutrient status and microorganism amount of the soil were studied after pure Larix olgensis plantation was changed to mixed plantation in Linkou Forest Bureau of Heilongjiang Province.The results showed that the difference of soil bulk density and soil total porosity of Fraxinus belt,Larix-Fraxinus belt,Larix belt,Larx-Juglans belt and Juglans belt was not significant,but that of different soil layer in the same plantation belt was significant,and the value reduced with soil layer decline.The amount of soil organic matter,total nutrient elements and available nutrient elements reduced with soil layer decline except total K.The nutrient amount of hardwood belt and mixed belt was higher than that of Larix olgensis belt,the amount of total N,total P and total K in soil layer of 0-10 cm increased maximum 13.99%,8.00% and 11.23%,and available N,available P and available K in soil layer of 0-10 cm increased maximum 18.84%,12.37% and 6.71% respectively.Most part of microorganism distributed in the soil layer of 0-20 cm,and their amount reduced with soil layer decline.The amount difference of total microorganism,bacterial,fungus and actinomycetes of different belt plantation was significant,of which the decline order of total microorganism amount was Fraxinus belt,Larix-Fraxinus belt,Larix-Juglans belt,Juglans belt and Larix belt.Study results would provide a scientific base for Larix olgensis pure plantation improvement.