不同种植年限人工林土壤养分变化特征
Change Characteristics of Soil Nutrients in Plantations with Different Planting Years

人工林更新对土壤养分特性的影响，至今还缺乏深入认识。本研究分析了不同林龄阶段云南松人工林土壤养分的变化特征。结果表明，人工林更新对土壤粗颗粒影响较大，与幼龄林和中龄林相比，近熟林和成熟林土壤砂粒含量有所增加。人工造林使土壤酸性增加，土壤交换性酸随林龄增加呈上升趋势。近熟林和成熟林土壤交换性酸显著高于幼龄林和中龄林。与幼龄林和中龄林相比，近熟林交换性酸分别增加了32.14%和19.35%，成熟林分别增加46.42%和59.00%。土壤有机质和全氮含量随林龄的增加呈先增加后减少的趋势。土壤全P含量随林龄增加的变化趋势不明显，全钾含量随林龄增加呈先减少后增加趋势。
Until now little is known about impact of plantation on the soil nutrient characteristics. Nutrient properties of soil in plantations with different growing ages have been analyzed in this study. The results indicated that afforestation had a profound effect on coarse soil particles. The sand grain content in near-mature forest and mature forest increased abruptly, compared to young and mid-dle-aged forests. Artificial afforestation increased soil acidity and there is a general increase in soil exchangeable acid with growing plantation ages. Soil exchangeable in near-mature forest and mature forest is higher than that in young and middle-aged forests. Soil exchangeable acid in near-mature forest increased by 32.14% and 19.35% compared to young and middle-aged forests and that in mature forest increased by 46.42% and 59.00%. Soil organic matter content first in-creases and then decreases with growing plantation ages, which is consistent with change of soil total N content. There is no obvious change trend in total P content. Soil total K content first de-creases and then increases with growing plantation ages.