覆土厚度对中国沙棘幼苗出土及生长的影响

Effects of Covering Soil Thickness on Seedling Emergence and Growth of Hippophae rhamnoides subsp.Sinensis

中国沙棘是我国北方干旱、半干旱地区优良的多用途树种,但干旱往往使其种群衰退。为将其引种到降水较为充沛的滇中高原,选取该区云南松林土壤并设置0.5 cm、1.0 cm、1.5 cm、2.0 cm、2.5 cm的覆土厚度,研究覆土厚度对中国沙棘幼苗出土、生长、生物量及其分配的影响,以期为沙棘育苗提供科学依据。结果表明:覆土厚度对中国沙棘出苗过程产生影响,沙棘出苗天数、到达出苗高峰的天数随着覆土厚度的增加而推迟,到达出苗高峰的出苗数随着覆土加厚而下降。覆土厚度对中国沙棘出苗情况、幼苗生长、生物量及其分配产生极显著或显著的影响,沙棘出苗率、出苗指数,地径、高度、根长,总干重、根干重、茎干重、叶干重、单株干重及叶片比均随着覆土厚度的增加而降低,这些指标均与覆土厚度呈极显著的负相关关系;根比、茎比、根冠比均随着覆土厚度的增加而增大,这些指标均与覆土厚度呈极显著的正相关关系。

Hippophae rhamnoides subsp. sinensis is an excellent multipurpose tree species in arid and semi-arid areas ofnorth China, but drought often causes its population decline. In order to introduce it to the central Yunnan plateau withabundant precipitation, the covering soil thickness of 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm and 2.5 cm were selected. The effects ofcovering soil thickness on the seedling emergence, growth, biomass and its allocation of H. rhamnoides seedlings werestudied, so as to provide scientific basis for seedling raising of H. rhamnoides. The results showed the thickness of theoverlying soil has an impact on the emergence process of the seedling, the emergence days of H. rhamnoides and the days tothe emergence peak were delayed with the increase of covering soil thickness. The number of seedlings to the peak ofemergence decreased with the thickening of the soil cover. The covering soil thickness has a significant effect on seedlingemergence, the seedling growth, biomass and its allocation. Seedling emergence ratio, seedling emergence index, grounddiameter, height, root length, total dry weight, root dry weight, stem dry weight, leaf dry weight, single plant dry weight andleaf ratio decreased with the increase of the soil thickness, these indexes showed a very significant negative correlation withthe soil thickness. Root ratio, stem ratio, root/shoot ratio increased with the increase of the covering soil thickness, there wasa significant positive correlation between these indexes and the covering soil thickness.