盐地碱蓬在高盐碱土环境中的生态学意义

Ecological Significance of Planting Suaeda salsa in Saline / Alkali Soils in the Lop Nur Potash Mine

以罗布泊钾盐矿区人工植被生态示范区种植的盐地碱蓬(Suaeda salsa)为对象,重点研究不同土壤类型对植物生长的影响以及盐地碱蓬在盐碱土改良中的生态学意义。结果显示:全换土区植物个体生长较其他土壤类型生长良好,而炉渣区生长相对较慢,这说明好的土壤环境利于植物的生长;对于炉渣区而言,虽然其含盐量不是最高,但因为其孔隙度大的物理性质使其保水力相对较差,因此,植物生长相对最差。而原状土区虽然植物发芽存活率低,植被盖度低,但是存活的个体生长良好,说明盐地碱蓬一旦适应了盐土环境,高盐土环境不会对其生长产生较大影响。根冠比结果表明,原状土区>炉渣区>炉渣+换土区>全换土区,这说明在较差的土壤环境中(高盐/高孔隙度),植物为了更好的生存,必须发展出较为强大的根系,以获取更多的养分和水分来维持生活,这正是植物适应外界胁迫环境的一种生态机制;对于土壤盐分和养分的研究结果显示:在盐碱土环境中种植盐地碱蓬后,土壤中的有机碳含量,全氮、全磷和全钾含量随着种植年限的增加而逐年增加。然而,其盐分含量和p H在原状土区有了不同程度的减小,说明盐地碱蓬有利于该区土壤盐碱性的降低以及土壤养分的积累。

Lop Nur is one of the most serious salinization regions in the world. In this case,saline soil improvement and ecological restoration plays an important role in improving the ecological landscape,microclimate and living environment for Lop Nur Potash mine. This study was conducted in the Lop Nur potash mining artificial vegetation ecological demonstration area,the planted Suaeda salsa was selected to study the different soil types effects on plant growth and whole replacement soil than other soil types,and relatively grew slowly in the slag zone,indicating that good soil environment is conducive to the growth of plants; for slag zone,although the salt content was not the highest,the large porosity make it have a poor water retention capacity,and therefore,plants in this zone grew not well. In the original soil zone,although the germination and survival rate was lower,the survival individual grew well,which indicating that once Suaeda salsa adapted to saline soil environment,high salinity will not influence its growth. The root shoot ratio results showed that the original soil zone〉slag zone〉slag ＋ replacement soil zone〉 whole replace soil zone,indicating that the plants had to develop a more powerful roots to get more nutrients and water to survive better in the poor soil environment（ high salt / high porosity）,such phenomenon is a kind of ecological mechanisms of plant adaptation to stress environment. The results of soil chemical properties after Suaeda salsa have been planted showed that： soil organic carbon content,total nitrogen,total phosphorus and total potassium content increased with the growing year. while,it reduced the salt content and p H in the original soil area,indicating that Suaeda salsa plays an important role in reducing the soil salts and accumulation of soil nutrients in alkali-saline soil area.