橡胶树无性系PR107种植密度试验

Studies on Planting Density for Hevea Clone PR107

以橡胶树PR107为试验材料,采用固定行距,由不同的株距形成不同的种植密度,设500,667,833株/hm2 等3种种植密度。结果表明:(1)密度越大,对茎围生长的抑制作用越强烈,其个体间的分化现象也越严重;(2)树龄越长,同一群体内个体间的差异越大;(3)密度越大,单株年产干胶量越低,然而,由于单位面积有效割株与种植密度成正比,种植密度大的单位面积干胶产量也较高,667株/hm2和833株/hm2的单位面积干胶产量极显著高于500株/hm2的,前两者之间无显著差异;(4)种植密度对干胶含量有显著的影响,500株/hm2的干胶含量显著高于667株/hm2和833株/hm2的,后两者之间的干胶含量无显著差异;(5)种植密度在667株/hm2以下时,密度对树皮的生长和再生没有影响,密度达到833株/hm2时,树皮的生长受到明显的抑制;(6)不同种植密度间的风害断倒率和死皮停割率均无显著差异;(7)以提高单位面积干胶产量为主要目的多因素综合考虑,PR107的种植密度应以略低于667株/hm2为宜。

A comparison was made of the growth and dry rubber yield and other characters of Hevea clone PR107(Hevea brasiliensis)in three planting densities:500trees hm 2 ,667trees hm 2 and833trees hm 2 .PR107showed a marked difference in annual girth growth among these densities both before and after tapping.The rubber trees had low girth growth but high individual difference at high planting densities.The individual difference became greater in the same community with the tree age.Low density had a higher dry rubber yield per tree per year than the higher density.However,the high density tasks had a larger number of total tappable rubber trees,resulting in a higher accumulated yield than the low density tasks.The rubber plantations with667trees hm 2 and833trees hm 2 produced remarkably higher dry rubber yield than those with500trees hm 2 ,but the difference between667trees hm 2 and833trees hm 2 was not remarkable.The dry rubber content between667trees hm 2 and833trees/ha was not remarkably different,but remarkably lower than that of500trees hm 2 .The difference in bark growth between500trees hm 2 and667trees hm 2 was not obvious,and the growth of their barks was obviously faster than that of833trees hm 2 .These3planting densities showed no remarkable difference in wind and tapping tolerance.The optimum planting density for PR107was slightly less than667trees hm 2 when many factors with dry rubber yield per unit area as the main factor was considered.