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近几十年来的杨树大面积种植引发了人们对洞庭湖湿地生态系统生态环境恶化的担忧。本研究以11龄与5龄杨树林为对象,以邻近的典型湿地植被南荻为对照,拟阐明杨树人工林对土壤理化性质的影响。结果表明,对土壤物理特性而言,杨树的种植加速了土壤水分的散失,对水分改变的趋势随林龄的增加而增大;杨树人工林改变了土壤粒径组成,致使粘粒与粉粒的降低、砂粒的增加,砂粒化趋势随林龄的增大而增强;对土壤化学特性而言,杨树人工林导致土壤中层(20-60 cm)电导率的降低,以及下层(60-100 cm)pH值的升高,对土壤全磷含量无明显影响,总体上降低了土壤全钾含量;引起土壤40-60 cm全氮含量的降低,降低趋势随林龄的增加而增大。此外,两种杨树林对土壤全碳的影响不同,低林龄能降低土壤全碳含量,而高林龄有利于碳的增加。可见,大规模种植杨树导致土壤特性的重要改变必将对湿地生态系统产生深远的影响。
Poplar cultivation in recent decades led to concerns about the deteriorating ecological environment in the Dongting Lake wetland ecosystem. In this study, 11 and 5 years of poplar forest as the object, with the adjacent typical wetland vegetation Nan Di as a control, to clarify the poplar plantation on the physical and chemical properties of the soil. The results showed that for the physical characteristics of the soil, poplar planting accelerated the loss of soil moisture, and the trend of changing with water increased with the increase of age. Poplar plantation changed the composition of soil particle size, With the increase of age, the trend of grain size and grain size increased with the increase of age. In terms of soil chemical properties, poplar plantation decreased the conductivity of the middle layer (20-60 cm) -100 cm) had no significant effect on the total P content of the soil, but decreased the total K content of the soil as a whole; the total N content of the soil decreased at 40-60 cm, and the decreasing trend increased with the increase of the forest age . In addition, the impact of two kinds of poplar on soil total carbon is different, the low forest age can reduce the total carbon content of soil, while the high forest age is conducive to the increase of carbon. It can be seen that major changes in soil properties resulting from poplar cultivation on a large scale will surely have a profound impact on wetland ecosystems.