论文部分内容阅读
采用时空互代法,以黄土丘陵区不同林龄人工刺槐林为研究对象,以坡耕地和天然侧柏林为对照,分析植被恢复过程中土壤酶的演变特征。结果表明:坡耕地种植刺槐林后,土壤脲酶、蔗糖酶、磷酸酶、过氧化氢酶随林龄逐渐增加,纤维素酶呈波动式变化,50年后较坡耕地分别增加160.2%,281.8%,541.6%,92.6%,73.8%,但仍低于天然侧柏林,多酚氧化酶较坡耕地降低39.1%,淀粉酶则先降低后升高。相关性表明,脲酶、碱性磷酸酶、蔗糖酶、过氧化氢酶和多酚氧化酶与土壤养分因子相关性较强,可以作为评价土壤质量的生物学指标。土壤酶指数在刺槐生长前期较坡耕地显著增大,随后趋于稳定,25年后随林龄不断升高,50年时达到最大值,但仅为天然侧柏林的63.2%。侵蚀环境下的坡耕地由于人为活动干扰,土壤酶活性较低,种植刺槐林后,土壤酶活性显著提高,土壤质量显著改善,但要恢复到该区演替顶级群落的水平,还需要很长时间。
The temporal and spatial alternations were used to study the evolution characteristics of soil enzymes during the vegetation restoration process with the comparison of artificial forest of Robinia pseudoacacia with different ages in loess hilly region. The results showed that the soil urease, invertase, phosphatase and catalase gradually increased with the age increasing after the planting of Robinia pseudoacacia on sloping farmland, and the change of cellulase was fluctuating. After 50 years, the soil urease increased 160.2%, 281.8% , 541.6%, 92.6% and 73.8%, respectively, but still lower than that of natural Platycladus orientalis. Polyphenol oxidase decreased by 39.1% and that of amylase decreased first and then increased. The correlation showed that urease, alkaline phosphatase, sucrase, catalase and polyphenol oxidase had strong correlation with soil nutrient factors, which could be used as biological indicators to evaluate soil quality. The soil enzyme index increased significantly at the early stage of Robinia pseudoacacia cultivation and then stabilized. After 25 years, the soil enzyme index reached its maximum at 50 years, but only 63.2% of the natural. Due to the disturbance of human activities, the activity of soil enzyme in sloping farmland under erosion was low. After the Robinia pseudoacacia plantation was planted, the soil enzyme activity increased significantly and the soil quality improved significantly. However, it needed a long time to recover to the level of the top succession community in this area time.