冀北沙地人工林土壤逆转特征研究

Study on Soil Properties of Artificial Forest in the Northern Hebei

为了掌握零星沙地人工林营造后林地土壤的逆转变化特征,通过标准地调查,对榆树(Ulmus pumila)、侧柏(Platycladus orientalis)和小叶杨(Populus simonii)3个树种进行了调查。结果表明:人工固沙林不同程度地起到了拦截风沙、降低风蚀的作用,对改善输沙率以及土壤的机械组成、理化性质发挥了作用;不同林分的输沙率不同,但80%～90%的输沙集中发生在距离地面4 cm高度范围内,影响输沙量的主要林分结构因子是林分郁闭度,按输沙率大小排序9年生小叶杨林>7年生侧柏林>15年生小叶杨林>17年生侧柏林>7年生榆树林>=13年生榆树林;所有林地土壤的有机质、N素、P素仍然处于极低水平,呈极贫瘠状态,造林后地力的自然恢复进程非常缓慢。

Ulmuspumila, Platycladus orientalis and Populus simonii plantations on scattered sandy land were selected for sample plot investigation in the Northern Hebei province. The results showed that tested plantations played an important role in wind and sand break, wind erosion reducing lowering sand transporting rate, improving mechanical composition and physiochernical characteristics of sandy soil. Different stands had different sand transporting rates, but 80%-90% of sand was shifted only under the height of 4cm above ground. Canopy density of stands was the main influencing factor for mass of transported sand. The order of sand transporting rate was as follows： 9-year P. simonii〉7-year P. orientalis〉15-year P. slmonii 〉17-year P. orientalis 〉7,13-year U. pumila. The contents of organic, nitrogen and phosphorus in soil of all the sample stands were extremely low, and the courses of soil restoration were very slow.