华北平原沙地治理工程初期的改良土壤效应

分别在北京市郊的房山区、顺义区和昌平区选择沙地治理工程示范区,以附近的荒地为对照,测量不同植被类型下的土壤有机质、全氮、速效氮、速效磷和速效钾含量等指标,以对华北平原沙地治理工程初期土壤改良效应进行研究。结果表明：在3个示范区,不同类型的植被都在一定程度上改良了土壤。其中,房山区的毛白杨增加土壤有机质和全氮的效果最佳,刺槐增加土壤速效氮和速效钾的效果最佳,而油松增加土壤速效磷的效果最佳。顺义区的华山松,国槐和垂榆均有效增加了土壤有机质、全氮、速效氮和速效钾,而华山松和国槐增加土壤速效磷的效果较好。昌平区的桧柏增加土壤有机质、全氮、速效氮、速效磷和速效钾的效果最佳。因此,在沙地治理工程初期,植被即可在一定程度上改良林下土壤。

Soil Improvement Effect of Sand Control Project in Initial Stage in North China Plain

Demonstration areas for sand control project were selected in Fangshan District,Shunyi District Changping District of Beijing. Compared with nearby barren land, the content of soil organic matter, total nitrogen, available nitrogen,available phosphorus and available potassium of different vegetation types were measured;the soil improve- ment effect of sand control project in initial stage in North China Plain were studied . Result shows that： in three demonstration areas,different vegetation types improve soil to some extent. In Fangshan District, the effects of in- creasing soil organic matter ~ total nitrogen by Populus tomentosct is optimal than that of other two trees; the effects o{ increasing soil available nitrogen ~ potassium by Robinia pseudoacacia is optimal than that of other two trees;the effects of increasing soil available phosphorus by Pinus tabulaeformis is optimal than that of other two trees. In Shunyi District, Sophora japonica, Pinus armandi ~ Ulmus pumila vat. pendula increase soil organic matter, total nitrogen, available nitrogen and available potassium; the effects of increasing soil available phosphorus by P. armandi ~ S. japonica are optimal than that of U. pumila var. pendula. In Changping District,the effects of increasing soil organic matter, total nitrogen, available nitrogen, available phosphorus ~ available potassium by Juniperus chinensis is optimal than that of other two trees. Therefore, vegetation can improve soil understory to some extent of sand control project in the initial stage.