高寒河谷流动沙地生境因子变化及其对播种期的影响  

Variations of Habitat Factors on Sand Dunes in the Alpine Valley and Its Influences on the Best Sowing Period

作　　者：李海东[1] 沈渭寿[1] 燕守广[1] 王涛[1] 唐军[2] 

机构地区：[1]环境保护部南京环境科学研究所,江苏南京210042 [2]中国环境科学研究院地下水与环境系统工程创新基地,北京100012

出　　处：《山地学报》2013年第6期647-655,共9页Mountain Research

基　　金：国家自然科学基金(41301611);江苏省自然科学基金(BK20130103);环境保护部南京环境科学研究所中央级公益性科研院所基本科研业务专项(NIES2011);国家环保公益性行业科研专项(200809010)资助~~

摘　　要：在雅鲁藏布江中游河谷，野外观测了流动沙地植被恢复试验期间的生境因子（降水、地温、土壤水分和风沙运动），结合文献[13]所报道的2008--2011年人工模拟飞播试验结果，分析了西藏高寒河谷流动沙地生境因子变化特征及其对最佳播种期的影响，以期为该区域正在进行的风沙化土地植被恢复提供依据。结果表明：1．降水量大小及其时间分布、不同类型沙地和沙丘坡向的土壤水分状况，决定着种子发芽、出苗和生长过程中能否得到持续不断的土壤水分补给，从而保证新播植物的根系前在越冬穿过旱季的干沙层，到达土壤水分较稳定的土层而顺利越冬。2．裸露于沙丘表面的种子因高温灼烧而干瘪、开裂，丧失发芽能力，尤其是刚出土的新生芽和幼苗对日灼很敏感，常出现3～4．5cm幼苗与地表接触的根茎结合部受日灼而死亡的现象。3．选择6月下旬前后作为植被恢复的最佳播种时间，通过河谷风向变换频繁引起的风沙运动，完成飞播植物种子的自然覆沙，既能满足新播植物种子发芽和出苗对土壤水分的需求，亦能提供相应的生长期，使植株高和根系长度生长到一定程度而保证新播苗顺利越冬。We carried out a continuous test of the field artificial seeding by choosing northern psammophyte species and native species of Tibet from 2008 to 2011, and the habitat factors including precipitation, soil temperature, soil moisture and sand movement, as well as the germination, emergence and growth processes of the testing plant spe- cies were observed simultaneously. Based on these, the best sowing period was discussed. The results showed that germination, emergence and growth processes were affected greatly by the amount of precipitation and its time distribution, soil moisture content of different aeolian sandy land types and sand dune parts. The plant roots could grow quickly under the condition of sufficient soil moisture, pass through the dry sand be t before the dry season coming, and get in touch with the groundwater table in the deeper soil bed. Due to the high temperature of sand, the seeds exposing on the dune surface mummified, cracked in great numbers and lost the ability of germination e- ventually. The sprout and seedling were sensitive from sunburn, and the withering and burning phenomenon could be seen everywhere when the drought event occured, and the sprout and seedling at the height of 3 to 4.5 cm died frequently. The best sowing period was from mid June to early July, and the wind exchange was frequent during this period, the seeds sowed by the field artificial seeding could be buried naturally by sand movement. This period not only meet the demand of the germination and emergence for soil moisture, but also provide a sufficient growing sea- son for the growth of plant size and plant roots, so that the plants could go through the winter and survive.

关 键 词：风沙化土地 植被恢复 生境因子 雅鲁藏布江高寒河谷 

分 类 号：Q151.5[生物学—普通生物学] X144[环境科学与工程—环境科学]