红松人工更新对表层土壤磷有效性及时效性的影响

Effects of Artificial Regeneration of Pinus koraiensis on Phosphorus Availability and Timeliness in Surface Soils

以小兴安岭阔叶红松林皆伐迹地人工更新的21、32、41、56年生红松人工林表层(0~10 cm)土壤为研究对象,采用Sui等修正后的Hedley磷素分级法对土壤样品进行连续浸提,研究不同林龄红松人工林土壤各形态磷素质量分数的差异及变化规律,分析人工更新对土壤磷有效性和时效性的影响。结果表明:水溶性磷(H_2OPi)、碳酸氢钠无机磷(NaHCO_3-Pi)、碳酸氢钠有机磷(NaHCO_3-Po)、氢氧化钠无机磷(NaOH-Pi)、氢氧化钠有机磷(NaOH-Po)与全磷质量分数的相关性较高,是影响红松人工林土壤磷库储量的重要磷源;H_2O-Pi对红松人工林土壤有效磷的贡献最大,直接通径系数为1.104,而NaHCO_3-Pi、NaOH-Po通过H_2O-Pi对土壤有效磷的间接通径系数分别为0.927、1.065。各组分质量分数随恢复年限延长而显著增加是导致土壤磷库储量增大的主要原因;红松人工更新56 a时,林地土壤有效磷供应能力基本接近阔叶红松原始林的水平,主要通过对H_2O-Pi、NaHCO_3-Pi、NaOH-Po的改变得以实现。

With the surface soil （0-10 cm） of Pinus koraiensis plantations from Korean pine broad-leaved forest in Xiaoxing’an Mountains with artificial regeneration after clear cutting for 21, 32, 41 and 56 a continuously by the Hedley phosphorous fractionation method （modified by Sui et al.）, we studied the differences and variation regulation of soil phosphorus forms of P.koraiensis plantation at different ages, and further analyzed the effect of artificial renewal on the timeliness effects of soil phosphorus. The H2O-Pi, NaHCO 3-Pi, NaHCO3-Po, NaOH-Pi, and NaOH-Po were highly correlated with total phosphorus content, respectively, showing that they were the most important phosphorus sources of soil phosphorus storage in P.koraiensis plantations. H2O-Pi played a greatest role in the soil available P in P.koraiensis plantation. The direct path coefficient was 1.104, and the indirect path coefficient between available P and NaHCO3-Pi and NaOH-Po through H2O-Pi were 0.927 and 1.065, respectively. Content increase of each phosphorous fractionation with recovery period increasing was the main reason for final increase of soil phosphorus reserves. Therefore, at 56 a of the soil phosphorus availability, P.koraiensis plantations were similar to natural Korean pine broad-leaved forest in the Xiaoxing’an Mountains, by changing H2O-Pi, NaHCO3-Pi and NaOH-Po.