Research on seed obstacles to the regeneration of Haloxylon ammodendron forest in the lower reaches of Shiyang River
Natural regeneration disorder is one of the primary reasons for the decline of artificial Haloxylon ammodendron forest.In order to study the relationship between the regeneration difficulty of artificial H.ammodendron forest and its seed in Shiyang River Basin,the effects of soil seed bank,soil texture depth and desert insect feeding on seed germination and seedling emergence of artificial H.ammodendron forest in different site conditions were studied.The results showed that there were significant differences in species composition and density in soil seed banks of mobile,semi-fixed and fixed sites in June,but the seeds of H.ammodendron had lost their viability at that time.In three different soil textures,according to the different soil physical properties and burial depth,when the burial depth was 0 cm,the highest proportion of fine sand 20-200 μm soil texture had the best seed emergence rate.The seed emergence rate of H.ammodendron was the best when the depth of burial was 1 cm,the proportion of coarse sand was 200-2 000 μm,and the three soil textures were unfavorable to seed growth when the depth of burial was 2 cm.The sprouts of H.ammodendron were more attractive to desert insects than the seeds.The non-selective feeding rate of desert insects on the seeds and sprouts of H.ammodendron under high humidity conditions was lower than that under dry conditions.The difficult regeneration of artificial H.ammodendron forest in Shiyang River Basin is not only closely related to the short life span of H.ammodendron seeds,but also directly related to soil texture,seed burial depth and desert insect predation.
万方数据
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