金沙江干热河谷3个造林树种裸根1年生苗的育苗密度研究

A Study on Seeding Density in Bare Root Seedling Raising of Three Planting Species in Hot-dry Valley of Jinsha River

对川楝、新银合欢、苏门答腊金合欢3个金沙江干热河谷上段区主要造林树种不同育苗密度所培育裸根1年生苗的光生理效应、苗木的形态质量及其经济效益进行了研究。在其他育苗措施相同的情况下,苗木密度是决定其苗木质量的主要因素。随着苗木密度的增大,3树种裸根1年生苗木的总体质量随之下降,以低密度时为佳。3个树种裸根1年生苗的一级苗产量分别在其苗木密度为75株/m2、100株/m2为高,而以75株/m2时最高,虽然此时苗木的净收入不是最大值,但投入/产出比值最大。而二、三级苗木产量随其密度的增加而增加,当苗木密度为150株/m2时三级苗所占百分率接近国家标准15%的许可界限。据此3个树种的裸根1年生苗培育的苗木密度以75株/m2、100株/m2为宜,而以75株/m2为最优。

The bare root seedling quality and economic benefit of Melia toosendan, Leucaena leucocephala cv. Salvador and Acacia glauca grew at different nursery density were studied. Nursery density is an important factor on seedling quality. With the nursery density increasing, the quality of seedhng decreases. The highest output of 100 days old grade one seedling of three species occurred at the density of 75 seedhngs/m^2, 100 seedlings/m^2 and 75 seedlings/m^2 respectively, although the pure income at these density were not the biggest, the input/output were the biggest. The output of grade two and grade three seedlings increased as the nursery density were increased. Under the density of 150 seedlings/m^2, the percentage of grade three seedling was close to the permission point of 15 %. Based on this study, it was proposed that the proper nursery density for these three species were 75 seedlings/m^2, 100 seedlings/m^2 and 75 seedlings/m^2 respectively.