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黄河三角洲地区的刺槐人工林生长20年后在环境胁迫下发生了不同程度的衰退。为了探讨林地土壤对环境胁迫的响应,采用时空序列转换的方法,开展了本项研究。结果表明,未退化、轻度退化刺槐林土壤含盐量在空间上表现出明显变化,随着土层的加深,含盐量逐渐升高,中度退化的林地含盐量表现出先降低后提高的趋势,而重度退化的刺槐林含盐量在空间分布上逐渐降低。轻度退化、中度退化、重度退化的刺槐林林地的土壤容重与未退化林地相比分别增加了5.75%、8.63%、14.4%;总孔隙度降低了7.4%、10.6%、15.3%。与未退化林相比,轻度退化、中度退化、重度退化的刺槐林的土壤有机质(全层)含量下降了27.1%、48.7%和56.6%;全氮则分别下降了9.9%、17.9%、32.1%;速效N下降了29.3%、36.7%、43.6%;速效P含量也出现递减。随着刺槐林退化程度的不断加剧,脲酶活性不断降低,轻度退化、中度退化、重度退化的刺槐林地土壤脲酶活性分别为未退化林地的87.5、56.9%、43.3%;过氧化物酶也呈现类似的趋势,分别为未退化林地的90.8%、77.2%和64.7%。
After 20 years of growth of Robinia pseudoacacia plantations in the Yellow River Delta, some degree of decline occurred under environmental stress. In order to explore the responses of forest soils to environmental stress, this study was carried out using the method of spatial-temporal sequence transformation. The results showed that the soil salt content of unskilled and mildly degraded Robinia pseudoacacia forest changed obviously in space. With the deepening of the soil layer, the salt content increased gradually. However, the salt content of moderate degraded forestland decreased first and then increased While that of heavily degraded Robinia pseudoacacia forest decreased gradually in spatial distribution. The soil bulk density of the mildly degraded, moderately degraded, severely degraded locust forest land increased by 5.75%, 8.63%, 14.4% respectively compared with the non-degraded forestland, and the total porosity decreased by 7.4%, 10.6%, 15.3%. Compared with the non-degenerated forest, the content of soil organic matter (full layer) in the degraded, moderately degraded and heavily degraded locusts decreased by 27.1%, 48.7% and 56.6%, while the total nitrogen decreased by 9.9% and 17.9% 32.1%; available N decreased by 29.3%, 36.7%, 43.6%; available P content also decreased. With the increasing degree of degeneration of Robinia pseudoacacia, the urease activity decreased, while the soil urease activity of the degraded, moderately degraded and severely degraded Robinia pseudoacacia forests were87.5,56.9% and43.3% of the non-degraded forestland respectively. The peroxidase A similar trend was observed, accounting for 90.8%, 77.2% and 64.7% of the non-degraded forest areas respectively.