刺槐和侧柏人工林有效根系密度分布规律研究  

Distribution characteristics of effective root density in the planted Robinia pseudoacacia and Platycladus orientalis forest site

作　　者：王进鑫[1] 王迪海[1] 刘广全[1] 

机构地区：[1]西北农林科技大学,陕西杨陵712100

出　　处：《西北植物学报》2004年第13期2208-2214,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家重点基础研究发展规划项目 G19990 43 60 2 ;国家 十五 重点科技攻关项目 2 0 0 1BA5 10 B0 10 3

摘　　要：通过分层分段挖掘法 ,对 13龄刺槐、侧柏人工林 ,根区有效根长密度和根重密度的空间分布进行了研究 .结果表明 ,尽管刺槐根系分布深度是侧柏的 2倍多 ,但平均有效根长密度只有侧柏的 4 4 .5 % .在垂直方向上 ,两树种有效根系主要分布在 0～ 6 0 cm土层内 ,然而最大有效根长密度却均位于距地表 0～ 30 cm以内 .其中 ,刺槐 0～30 cm区域内有效根长占总有效根长的 5 1.5 8% ,侧柏占 5 8.38% ;刺槐有效根干重占总有效根干重的 6 3.0 1% ,侧柏占 71.0 9% ;两树种根系密度分布均随土层深度增加而呈指数形式递减 .在水平方向上 ,刺槐有效根系密度呈二次抛物线型分布、最大有效根长或根密度以距树干 30～ 90 cm处最大 ;侧柏有效根系密度则随着距主干距离的增大而减小 .非线性参数拟合分析表明 ,采用 RD=EXP A+BX +CZ 函数模型 。The distributions of roots density have important implications for the nutrient cycling, water uptake and use, as well as for the whole ecosystem hydrological balance. Although there have been many reports on roots for forest, few of them was conducted for plantations on Loess plateau, especially for the plantations of black locust (Robinia pseudoacacia L.) and oriental arborvitae (Platycladus orientalis Franco) which play a greatly important role in water and soil conservation in the region. By means of dig methods from left to right and from up to down, the spatial density distributions of effective root in length and weight were studied in the planted forest sites of 13-year-old black locust and oriental arborvitae, respectively. The goals of this paper were to 1) examine the association of root density with tree species and locations at different soil depths as well as distance far away from the stem, and 2) develop a two-dimensional distribution models of effective root density for black locust and oriental arborvitae which were essential for the study of water uptake and dynamic simulation for soil water in the roots zone. The results were showed that although the depth of black locust root is as twice as that of oriental arborvitae, the average density of effective roots for the black locust is only 44.5 % of the oriental arborvitaes. At the vertical direction, the effective roots mainly distributed in the range of 0～60 cm below the surface for both the black locust and oriental arborvitae, but the maximum value was in the range of 0～30 cm below the surface. Of which the ratio of effective root length in the layer to effective root length in total is 51.58 % for black locust and 58.38% for oriental arborvitae, and the ratio of effective root weight in the layer to effective root weight in total is 63.01 % for black locust and 71.09 % for oriental arborvitae. The density distribution of effective roots for two species is decrease at an exponent function with the increase in soil depth. At the horizontal

关 键 词：人工林 细根 根系密度 空间分布 刺槐 侧柏 

分 类 号：Q944.54[生物学—植物学] S792.27[农业科学—林木遗传育种]