青海大通中国沙棘人工林对土壤有机质和含氮量的影响

测定了 1 4a生沙棘纯林及沙棘×青海云杉和沙棘×白桦×青杨以及无林对照剖面 2 0个土样的有机质、全氮及速效氮含量 ,比较研究了青海大通黄河上游沙棘人工林对土壤系统的微观生态效应。结果表明 :①在青海大通营造沙棘林能在短时间内迅速提高土壤有机质含量。 1 4a生沙棘纯林及混交林 0 - 80cm土层平均有机质含量较对照分别提高 1 79.35 %和1 67.68% ,0 - 80cm土层平均有机质含量较对照分别增加 5 9.1 44和 41 .0 2t/hm2 ;②沙棘的固氮作用使土壤氮素含量在短期内大幅度提高 ,沙棘纯林及混交林 0 - 80cm的贮蛋量较对照分别增加 3.1 1 9t/hm2 和 2 .5 74t/hm2 ,速效氮贮量增加 30 0 .69kg/hm2 和 2 33.5 5kg/hm2 ;③沙棘人工林对土壤有机质和全氮的增长作用随土壤深度增加而降低 ,而速效氮在土壤中下层高于表层。④ 1 4a生沙棘纯林的培肥效应高于沙棘混交林 ,而沙棘与针叶树混交培肥效果又低于沙棘与阔叶树混交。

Effects of Artificial Chinese Seabucksor Forest on the Content of Soil Organic Matter and Total Nitrogen in DaTong County of QingHai

The contents of organic matter, total and available nitrogen of 20 soil profile were determinated respectively in pure seabucksor forest in 14 years and seabucksor ×QingHai spruce forest and seabucksor ×birch ×poplar qforest and control experimental land. The soil micro-ecosystem was researched in DaTong County of upper stream of The Yellow River. The results were as follows: (1) seabucksor forest can rapidly increase the content of soil organic matter in short time. Comparing with control experimental profile, in 0～80cm solum the organic matter was increased 59.1, 41.0 t/hm 2 in 14 years of pure seabucksor and mixed forest respectively , and increasing percentage respectively were 179.35% and 167.68%. (2) The fixed nitrogen function of seabucksor made the content of soil nitrogen increase on a large scale. Comparing with control experimental profile, in 0～80cm solum the content of total nitrogen was respectively increased 3.119, 2.574 t/hm 2, and available nitrogen 300.69, 233.55 kg/hm 2 in pure seabucksor and mixed forest. (3) With the improvement of soil depth, the contents of organic matter and total nitrogen were decreased in artificial seabucksor forest. However, the content of available nitrogen in lower and middle solum was higher than upper solum. (4) The fertilization effects of 14 years of pure seabucksor forest was higher than mixed seabucksor forest, and the fertilization effects of mixed seabucksor with conifer was lower than mixed seabucksor with poplar.