摘要
在黄河三角洲地区,由于河水携带大量泥沙在入海口淤积,每年形成一定面积的陆地。新生陆地一般营养丰富,适宜耕作,常常被开垦为耕地。由于干旱,天然降雨少,土壤蒸发量大,导致深层土壤水分沿毛细管上升,可溶性盐分离子随之上升到土壤表层,水分蒸发后,盐分离子在土壤表层积累,从而发生土壤盐渍化。进行农业耕作20年后,土壤返盐严重,不再适宜继续耕种。除此之外,还有不同的土地利用方式。本研究选择了5种利用方式,分别测定了土壤溶液电导率、N、P、K、有机质含量等营养状况以及几种土壤酶活性,结果表明:耕地(E)的土壤含盐量最低,营养水平最高,土壤酶活性也最高。草地(G)的土壤含盐量比较高,而营养水平、土壤酶活性也比较高。灌木林地(S)的土壤含盐量比较高,而营养水平、土壤酶活性却比较低,属于立地条件较差的地块。与盐碱荒地(U)相比,它的含盐量降低不少,而营养水平、土壤酶活性也有所改善,说明通过栽植耐盐树木,提高植被覆盖率来改良盐碱荒地是可行的。林地(F和M F)的土壤含盐量比较低,营养水平、土壤酶活性比较高。另外,刺槐与紫穗槐混交林的效果很好,一方面它们都有一定的耐盐性,另一方面都是固氮植物,能够自我积累营养。
Owing to sands allusion, a certain area of new-formed land annually occurred in Yellow river delta （YRD） region. These lands were characterized with rich nutrients, hence usually were exploited as farmlands. However soil salinisation frequently came forth due to drought and high evaporation when these lands were cultivated. Thereby there were various land use systems in YRD area. In order to approach land degradation mechanism, 5 typical land use patterns were chosen, soil samples were specifically collected and soil chemical properties were analyzed, soil enzymes （Invertase, Phosphatases, Catalases） activity as well. The results indicated that soil salinity was lowest, nutrition was best, and soil enzymes activity was highest for arable land. For grassland, soil quality became a little bad, as these lands came from degraded farmlands. For shrub land, soil conditions got much more badly, as these shrubs grew in salinized land. In forested lands including pure stands and mixed forests, soil nutrition and enzymes activity were better, salts concentration also was lower, which implied that trees could ameliorate soil conditions to some extent. Among the five land use types, no doubt, soil quality was worst in wild lands.
出处
《水土保持学报》
CSCD
北大核心
2006年第4期98-101,159,共5页
Journal of Soil and Water Conservation
基金
国家"十五"重大攻关项目"中国森林生态网络体系"线"的研究与示范"(2004BA516A13)
关键词
土地利用方式
土壤酶活性
土壤化学性状
land use systems
soil enzymes activity
soil chemical properties
