川西高原退化草地的中国沙棘生长及土壤养分研究

以川西高原退化草地人工种植1~3年的中国沙棘为研究对象,分析了其生长、土壤养分及叶片养分回收情况。结果显示:随着种植年限的增加,沙棘幼苗株高、冠幅、叶长及叶宽逐渐升高,侧枝数目和根长先升后降。与同区域康定柳相比,种植3年的中国沙棘根际土壤中全磷、有效磷和有机质含量较高,水解性氮含量相对较低。中国沙棘叶氮、磷含量(Ng、Pg)分别为23.24 mg·g^-1和1.84 mg·g^-1,低于北方典型沙生植物叶片养分水平(27.42 mg·g^-1和3.68 mg·g^-1),叶磷回收效率(PRE)高达69.35%,受土壤有效磷供应不足的影响;康定柳叶磷回收效率为负值,叶氮回收效率(NRE)达59.88%,受土壤有效氮的限制更多,中国沙棘根系固氮作用能够补偿退化草地上土壤氮供应不足的限制。

A Study of the Growth and Soil Nutrients of Hippophae rhamnoides on Degraded Grassland in Western Sichuan Plateau

In this paper studies were made of the growth,soil nutrient and leaf nutrient resorption of Hippophae rhamnoides,which was cultivated on degraded grassland for 1~3 years in Western Sichuan plateau.The results showed that,with the increase of planting years,the plant height,crown width,leaf length and leaf width of seedlings increased,the number of lateral branches and root length first increased and then decreased.Compared with Salix paraplesia in the same area,the contents of total phosphorus,available phosphorus and organic matter were higher in the rhizosphere soil of H.rhamnoides,and the contents of hydrolytic nitrogen were lower.The nitrogen and phosphorus contents(Ng and Pg) in the leaves of H.rhamnoides were 23.24 mg·g^-1 and 1.84 mg·g^-1 respectively,which were lower than typical northern psammophyte(27.42 mg·g^-1 and 3.68 mg·g^-1).The leaf phosphorus recovery efficiency(PRE) was as high as 69.35% in H.rhamnoides,which was restricted by the insufficient supply of phosphorus in the soil.The leaf nitrogen recovery efficiency(NRE) was 59.88% in Salix paraplesia,which was more restricted by the advisability of nitrogen of the soil.The nitrogen fixation in the roots of H.rhamnoides could compensate for the insufficient supply of soil nitrogen in the degraded grassland.