黄土高原油松、侧柏与沙棘人工混交林生长及土壤特性研究

Studies on the Growth and Soil Properties of Pinus tabulaeformis,Platycladus orientalis and Hippophae rhamnoides Mixed Plantation on Loess Plateau

对混交林生长和土壤特性进行了研究,结果表明:油松、侧柏是主根型树种,垂直根系主要分布在40～80 cm,沙棘为侧根型树种,根系主要分布在10～40 cm,二者分布协调,种间根系生长无排斥现象。混交林平均高度、胸径、蓄积量、生物量较纯林高14.5%、27.4%、62.2%、42.1%;油松、侧柏、沙棘混交林的叶量分别比纯林高14.9%、13.5%、6.3%,叶绿素含量高21.0%、36.8%、3.1%,叶子中N、K2O、CaO含量较纯林高;混交林土壤容重和坚实度比纯林低9.6%和18.0%,孔隙度、通气度、持水量和含水量比油松纯林分别提高13.8%、20.1%、15.7%、4.8%,比侧柏纯林分别提高7.9%、11.6%、5.7%、12.7%。不同土层土壤容重和坚实度由上到下逐渐增大,土壤中层持水量、含水量最高,低层次之,表层最低;孔隙度和通气度表层较高,向下逐渐减少。混交林有机质、全N、P2O5、速效P、速效K高于纯林。

The paper measured and analyzed the growing and soil properties of Pinus tabulaeformis, Platycladus orientalis and Hippophae rharnnoides mixed plantation on Loess Plateau. The results showed P. tabulaeformis and P. orientalis were the main root type and their vertical root systems were mainly distributed between the soil depth of 40-80 cm. H. rhamnoides was the branch root type and its root system was mainly distributed between the soil depth of 10-40 cm. The root systems of two tree species could grow without exclusion. The mean height, trunk diameter, volume and biomass of the trees in mixed plantation were 14. 5%, 27. 4%, 62. 2% and 42. 1% higher than those in pure plantation. The mean leaf weights and chlorophyll contents of P. tabulaeformis, P. orientalis and H. rharnnoides in mixed plantation were 14. 9%,13.5%,6.3% and 21.0%,36.8%,3. 1% higher than those in pure plantation. The N, KzO and CaO contents in the leaves all were increased. The soil volume weight and compactness in mixed plantation were reduced by 9.6% and 18.0%The porosity, air permeability, water- holding capacity and water content in H. rharnnoides mixed plantation were 13.8%,20. 1%,15.7% and 4. 8% higher than those in P. tabulaeformis pure plantation and 7. 9%,11.6%,5.7% and 12. 7% respectively higher than those in pure plantation of P. orientalis. The soil organic matter, total N, P2O5, available P and K increased in mixed plantation.