【作者】 景维杰；

【导师】 梁宗锁； 韩蕊莲；

【作者基本信息】 西北农林科技大学 ， 植物学， 2004， 硕士

【摘要】 近年来生态恢复的理论研究和实践证明，植被的恢复是黄土高原地区水土保持、生态环境建设、农林牧业持续发展的根本措施。水分是制约该区植被恢复和生长及生态重建的主要生态限制因子。在植被恢复过程中，植物对水分的需求与水资源的不足之间的矛盾表现的愈来愈明显。因此，如何利用有限的水分资源提高植被覆盖率已经成为该区面临的亟待解决的问题之一。针对黄土高原气候特点和植物水分供需矛盾出发，在该区对造林中主要的抗旱技术影响造林成活和幼林生长的生理生态机制进行研究。分析不同立地土壤水分分布特征及造林效果。通过覆盖措施改善植物根系周围土壤水分状况，提高土壤水分利用率。采取集水措施提高自然降水的有效利用率。通过使用生化制剂借以改善植物根系周围土壤水分状况和林木本身的吸水能力。经过2002年—2003年的野外实地研究、取样分析，获得的主要研究结果如下：1、不同立地条件通过土壤水分分布影响造林成活率和幼林生长的研究结果表明：在退耕4年的坡地上，坡向、海拔、坡度对水分分布的影响最大。不同立地条件下，幼林成活率具显著差异，生长和生物量分配表现出不同的生长策略。在阴坡上位、阴坡下位、阳坡上位三种立地条件下，播种后三年柠条地上部分生物量分别占总生物量比例分别为71.8%、67.8%、62.3%。阳坡刺槐、山杏幼林单位叶面积干重大于阴坡值；阴坡幼林叶片水分饱和亏小于阳坡对应值。阴坡下位紫穗槐幼林植株地径单位截面积所支持的叶片面积、叶干重占地上部分生物量比例皆大于阴坡上位对应值，且具不同的模拟曲线。阴坡下位紫穗槐幼林分枝基径截面积和分枝高度间模拟关系不同于上坡位。2、通过在坡面采取集水措施，提高自然降水有效利用率，从而促进幼林成活和生长。对不同坡面间距水平阶集水和所造幼林生长状况进行研究结果表明:水平阶较荒坡有明显的保水、集水效果。水平阶的集水、保水效果和所造林成活率及幼林生长效果与其间距的增加成反向变化。3、黄土高原地区覆盖和集水抗旱效果研究表明：根据幼林生长研究结果和黄土高原地区气候特点表明采取覆盖和集水措施相结合在造林过程中会取得更好得效果。上半年气候多风干燥，覆盖措施抗旱效果较好；下半年降水较集中，强度大，在坡地采取集水措施会提高降水的利用率。4、生根粉、保水剂处理通过不同生理作用机制，提高侧柏、油松、等造林成活率和幼林株高、地径及新枝的生长。生根粉通过促使植株根系，尤其是侧根生长增强植株吸水能力抗旱；保水剂作用在于减少植株水分散失抗旱。更多还原

【Abstract】 Loess Plateau is one of the fragile environments. The economic development is restricted seriously by arid and water and soil run off. It has been proved that the recovery and construction of plants in this region is the basic measure of water and soil conversation，environment construct and the development of agriculture, forestry, stock raising，However, the contradictions among forests, plants and soil water are obviously in the process of plants revive because of water shortage. Therefore, how to utilize the water and increase the cover rate of pants is the urgent thing we must be do. This article studied the effects of the main anti-drought techniques on the physiological and ecological mechanism of the survival and growth of seedlings based on the climate and the water disparity and plant demand in Loess Plateau. That the water distribution and the survival and growth of young forest in different site condition of sloping field in Loess Plateau was studied. Covering measures with the plastic film or hasty to improve the soil water condition of root environments and the use of soil water. Catchments in sloping field can improve the use of precipitation. The use of chemical preparation can improve the soil water condition of root environments and the seedlings’ bibulous capacity. The result was follows:1．The effects of soil water distribution in different site on the seedlings’ survival and growth. The results showed that soil water distribution mainly depend on the gradient、exposure、and slope position. There is different survival of seedlings in different site condition. Seedlings have different strategic growth and biomass allocation in different site condition. The3-year Calophaca korshinskii Kom shoot to total biomass ration is 71.8% in lower shady slope, 67.8% in upper shady position, and 62.3% in solar position . The Locust and Wild Apricot’ leaf area index in shady slope are lower than that in solar position; but the leaf water deficit show inverse tendency. Amorpha fruticosa L. total area to stem area ration, and leaf/stem ration are higher in lower shady slope than that in upper shady position. Furthermore, there are different modules in different site condition.2．Terrace made in slope field can improve the use of precipitation to improve survival and growth of seedlings. The result was proven that the terrace has higher mass flow than that of slope; and the smaller row spacing the bigger the effect contributing to mass flow, the seedlings’ viability and growth. 3．Comparing the effect of fighting a drought between catchments and coving measures. The research of seedlings’ growth and the climate of Loess Plateau prove the fact that the combination of coving and catchments can give the better effect in the afforestation.Because in the first half of the year in Loess Plateau The climate is windy and arid ,coving measure is better than that of catchments ;and the ranginess become convergence in the last half , <WP=7>accordingly,catchment measure is better.4．Chemic preparations exert effect on improving seedlings’ ability of fighting a drought.Rooting powder (ABT) and Super Absorbent Polymers can improve the growth of height and diameter of Robinia pseudoacacia and Amorpha fruticosa L) through different ways. Rooting powder (ABT) can improve the throws of plant by facilitating rooting ,especially the side root. Super Absorbent Polymers fulfill it ‘function through resisting the water transpiration of leaf .更多还原