柳树农田防护林造林效果及遮荫作用研究

研究了沙埋深度对荒漠植物红砂幼苗出土和生长的影响.进行了0.1,2,3和5 cm共5个深度处理,每个处理5个重复.结果表明,出苗率与沙埋深度呈显著负相关,且集中在O-2 cm的沙埋深度,3cm沙埋深度只有1苗出土,5 cm沙埋深度没有出苗;随着沙埋深度增加,第一次出苗所需天数增加;幼苗生长高度受沙埋深度和生长时间的影响显著,相对高度生长率随沙埋深度增大而增大,幼苗高度随沙埋深度增加而降低,但生长一定阶段后,随着沙埋深度的增大,幼苗高度也增大;生物量并不随沙埋深度变化而变化,但生物量分配却随沙埋深度增大而更多地分配给地下部分,这种变化可将有限的种子能量传给地下茎.进而促进出苗.红砂幼苗出土和生长的最佳沙埋深度约为1 cm.

Effects of Farmland Shelterbelt by Willows and Their Shading Performances

The controlled experiment was conducted to test the effects of sand burial depth on seedling emergence and growth of Reaumuria Soongorica, investigate the optimal range of burial depth to maximize the seedling emergence and subsequent seedling growth, and assess seedling biomass allocation at different sand burial depths. In the burial experiment, emergence percentage had a significantly negative correlation with the sand burial depth and high seedling emergence concentrated in 0-2 cm layer. The number of days from sowing seeds to seedling emergence was significantly affected by sand burial depth, which increased with increasing depth. Seedlings height was significantly affected by both sand burial depth and growth time and the relative height growth rate increased with increasing depth. Therefore, seedling height decreased with increasing sand burial depth at the prophase and it increased with increasing sand burial depth at the anaphase. Seedling biomass was not significantly affected by sand burial depth, and however, more biomass was allocated to underground with increasing sand burial depth. Such morphological changes would amortize the limited seed reserve to facilitate emergence. The optimal burial depth for Reaumuria Soongorica was in the range of a shallow burial depth of 0-2 cm, approximately 1 cm.