广西桉树林取代马尾松林对土壤理化性质的影响

对广西钦州市钦南区巨尾桉林和马尾松林的土壤理化性质进行研究，旨在阐明桉树林取代马尾松林对土壤理化性质的影响。结果表明:①桉树林取代马尾松林后，0～60 cm土层的土壤密度、毛管孔隙度呈下降趋势，而0～20 cm土层的土壤总孔隙度和非毛管孔隙度稍有增加，但差异不显著（P为0.42～0.91）；②土壤最大持水量、毛管持水量和最小持水量相差不大，在各土层中的差异也不显著（P为0.79～0.89）；③土壤养分的变化，除桉树林的土壤全氮和速效钾（0～20 cm）含量比马尾松林低外，全钾、有效磷、交换性钙、交换性镁含量都高于马尾松林，而土壤有机质、pH值、全磷和水解氮相差不大；差异显著性检验结果表明，0～40 cm土层，桉树林与马尾松林的土壤有机质、pH值、全磷、水解性氮、速效钾、交换性钙的差异均不显著（P为0.14～0.99），0～20 cm土壤全钾和有效磷以及20～40 cm土壤全氮含量存在显著差异（P=0.05），而交换性镁在0～20 cm和20～40 cm土层存在显著差异（P=0.05）和极显著差异（P=0.008）。说明桉树 林取代马尾松林后，经过10年的林分生长，土壤物理性质和养分含量仍保持基本稳定，具有加速土壤氮素消耗、提高土壤有效磷和交换性镁的作用。 

Effects of eucalypt plantation replacing Masson pine forest on soil physiochemical properties in Guangxi,southern China

By studying the soil physiochemical properties of eucalypt (Eucalyptus grandis × E. urophyUa) plantation and Pinus massoniana forest in Qinnan Region, Qinzhou City of Guangxi, southern China, the objective of this study was to examine the effects of eucalypt plantations replacing P. Massoniana forest on the soil physiochemical properties. The results showed that:1) making a comparison between both types of forests, the soil bulk density and capillary porosity decreased in 0-60 cm soil layer and the soil total porosity and non-capillary porosity increased in 0-20 cm soil layer of eucalypt plantation, but that of both forests was not significant different (P ranged from 0.42-0.91, df=4), after eucalypt plantation replacing P. Massoniana forest;2) the maximum water holding capacity, capillary water holding capacity and minimum water holding capacity in different soil layers also were not significant different (P ranged from 0.79-0.89) between both types of forests;3) the content of total K, available P, exchangeable Ca, exchangeable Mg of eucalypt plantation was higher than that of P. Massoniana forest, and soil organic matter, pH value, total P and hydrolyable N were less different between both forests, except total N (0-40 cm soil layer) and available K (0-20 cm soil layer) of eucalypt plantation were less than that of P. Massoniana forest; test of the significance of difference indicated that soil organic matter, pH value, total P, hydrolyable N, available K and exchangeable Ca were not significant different (P ranged from 0.14-0.99) in 0-40 cm soil layer, and total K and available P in 0-20 cm soil layer and total N in 20-40 cm soil layer had a significant difference (P=0.05), exchangeable Mg, however, had significant or strong significant difference (P=0.05 in 0-20 cm and P=0.008 in 20-40 cm soil layer) between both forests. These implied that the soil physiochemical properties were stable, the consumption of soil nitrogen was accelerated and the content of soil available P and exchangeable Mg were improved, by ten years recovery after eucalypt plantations replacing P. Massoniana forest.