【作者】 米志英；

【导师】 高永；

【作者基本信息】 内蒙古农业大学 ， 水土保持与荒漠化防治， 2008， 博士

【摘要】 沙柳(Salix psammophila C.Wang et.C.Y.Yang)是库布齐沙漠广泛分布的优势灌木树种,耐旱,抗风蚀、耐沙埋,生长迅速,防风固沙、保持水土功效显著。沙柳还因纤维形态与材质良好成为造纸和人造板材的优良原料,是沙区重要的工业用材林树种。本文通过对库布齐沙漠沙柳种子寿命、育苗和营林技术、天然林复壮和更新等技术的对比研究,初步阐明了研究区沙柳的发育过程及其与关键因素的关系,探索沙柳的造林、营林技术和产业开发潜力及其生态功能的持续保育途径,为研究区生态与环境决策和沙柳资源的持续开发利用提供理论与技术支撑。通过研究,初步取得了如下进展:1)适当的贮藏处理可使沙柳种子寿命延长。室外暴露贮藏环境下的沙柳种子寿命是30d左右,室内贮藏的沙柳种子寿命是80d左右,10℃冷藏的沙柳种子寿命是300d左右,-10℃冷冻贮藏的沙柳种子寿命达到360d左右。通过试验可以延长沙柳种子寿命,具有促进沙产业可持续发展及生态环境恢复的实际意义。2)沙柳种子的萌发受到多个因素的综合作用。沙土含水率低于2%时沙柳种子不能萌发。覆薄膜有利于沙土水分的保存,在沙土含水率较低时有利于沙柳种子萌发。盐分可明显抑制沙柳种子萌发,同时抑制沙柳实生苗的茎生长。沙柳种子适宜的覆沙厚度是1.0mm～4.0mm。当覆沙达到7mm时种子出苗受到抑制。沙柳最适宜的发芽温度是25℃,当温度升到40℃时发芽率明显下降,而当降到10℃时种子发芽率也明显下降,达到5℃时沙柳种子尽管能发芽,但无茎生长。3)沙柳的着生基质越接近原生的基质条件,沙柳扦插生长也越具有优势。通透性好的沙基质有利于沙柳扦插成活。沙柳扦插苗头2年生长最快,3年后生长逐渐减退。4)经过回归分析得出:沙柳枝条长与生物量相关关系较为密切,沙柳实生苗枝条生物量模型采用枝条长为变量建立模型: y= 28.879x-22.537 (P<0.005)其中y:生物量(干重g)、x:枝条长(cm)5)沙柳根系趋向于迎风坡上部生长的特性与沙土水分差异、风蚀作用和温度相关,定量描述这一关系则有待于进一步的研究。6)适宜的插条处理可以有效促进沙柳的插条生长,保水剂的综合作用效果最好,经保水剂处理过的沙柳扦插成活率、平茬后第二年发芽枝条数明显增大(P<0.05),分别比对照增加61.0﹪、70.4﹪。设置沙障、地表平茬、常规平茬、施肥4种复壮更新技术措施对沙柳的高生长和地径生长均有显著促进作用(P<0.05)。施肥处理对沙柳的高生长效果比较显著,设立沙障的处理对沙柳的地径生长效果更好。更多还原

【Abstract】 Salix psammophila is one of important bushes in the Hobq Desert .It owns the qualities of drought resistance, wind-erosion resistance, sand-buried resistance, fastgrowing, sand-fixation, water and soil conservation. Salix psammophila was used as an excellent material in papermaking and artificial board due to its good fiber morphology As industrial timber it plays an important role in sand-land region Based on experiment and field investigation, the seed life, germination, seedling development, afforestation, natural rejuvenation, and cultivation for industrial use, of Salix psammophila were studied in the recent three years.The results showed that:1. Longivty of Salix psammophila seed can be prolonged through proper storage. Longivty of Salix psammophila seed exposed to outdoor condition was about 30d. Longivty of Salix psammophila seed stored under indoor condition was about 80d. And that of Salix psammophila seed stored at 10℃and -10℃was about 300 and 360 days, respectively.2. Seed germination characters of Salix psammophila were affected by several factors. Seed of Salix psammophila could not be germinating when soil moisture was below 2%.Covering with film was benefitable to water conservation in sand,and it could promote seed germination during low soil moisture. Seed germination was significantly restrained by all kinds of NaCl application. However, branches growth were stimulated by NaCl. The optimal sand thickness covering seeds was 1.0mm-4.0mm . When the sand was thicker than 7mm , seed germination would be restrained. The most suitable temperature for seed germination was 25℃.When the temperature was higher than 40℃, germination rate was reduced seriously. Same thing would happen when the temperature was lower than 10℃. Although Seed of Salix psammophila could germinate when the temperature was 5℃, it could not grow.3. The more likely to the original soil the cultivated soil for the Salix growth became, the better the Salix cuttings grow. Proper permeability of the sand soil was good to the cutting survival. Cutting seedlings of Salix psammophila grow fast for the first two year. Then, It would be growing slowly in the third years. [0]4. After correlation analysis of Salix psammophila root diameter and above-ground biomass, the following predictive model of seedlings was established. y= 28.879x-22.537 (P<0.005) Y: biomass (g) X: branch height (cm)5. Upward growth of Salix psammophila root along within the top sand was noticed in the windward slope. This was quite possibly due to the variation of soil moisture, wind erosion and temperature. Quantitative description of this process and related factors will be carried out in the future.6. Compared to CK, water-retaining agent could significantly promotes the survival rate, biomass and branch number of salix psammophila germinated in the second year (P<0.05). The survival rate and branch number germinated in the second year, treated with water-retaining agent, was increased by 61.0﹪and 70.4﹪, respectively. All four treatments put significant impacts on the growth of Salix cuttings, with fertilizer better to height growth and sand barrier more effective to stem diameter growth.更多还原