摘要
用土钻法研究了不同连栽代数杉木细根生长与分布 ,结果表明 ,杉木连栽 1代后 ,细根生物量明显减少 ,第 1代杉木活细根生物量的范围为 646.4～ 799.7g· m- 2 ,而第 2代则为 2 84 .4～ 536.9g· m- 2 .在一定距离范围内 ,离树体的距离越远 ,细根分布越少 .杉木连栽后 ,主要减少了表层土壤 ( 0～ 1 0 cm)细根的生长 .根系分泌物的分析表明 ,杉木连栽 1代后 ,根系阳离子 NH4 +、Na+、K+、Ca2 +、Mg2 +的分泌量没有变化 ,而阴离子 NO3-、Cl-、SO4 2 -、HPO4 2 -的量都减少 ,但只有 Cl- 和 HPO4 2 - 差异显著 ( P<0 .0 5) .第 2代杉木根系分泌物中的 HPO4 2 - 量仅为第 1代的 1 /65.根 -土界面磷交换过程的阐明有利于说明第 2代杉木根系 HPO4 2 - 分泌量减少的原因 .杉木连栽后 ,表层土壤细根生长的减少和根系分泌行为的改变可能是生产力下降的重要原因 .
Fine root growth and distribution were investigated by the soil coring method respectively in Chinese fir plantations of first and second rotations. Biomass of live fine roots decreased markedly after Chinese fir plantation continuously cropping for one rotation, with biomass of live fine root of first rotation ranging from 646.4 to 799.7 g/m 2 , and second rotation falling into 284.4～536.9 g/m 2 . The farther the sampling point from the tree per se, the less the biomass of live fine root to certain extent. Analysis of the root exudates showed that contents of cations NH 4 +、Na + 、K + 、Ca 2+ 、 Mg 2+ did not change after replanted with Chinese fir for one rotation, but contents of the anions NO 3 -、Cl -、 SO 4 2- 、 HPO 4 2- decreased, and significant differences for Cl -、HPO 4 2- were detected (P<0.05). The contents of Cl -、HPO 4 2- for the second rotation were only 1/4.7 and 1/65, respectively, of those in the first rotation. The decrease in growth of fine roots in 0～10 cm soil and change of root exudations could suggest the decline in productivity of the continuously cropped Chinese fir plantations.
出处
《生态学报》
CAS
CSCD
北大核心
2001年第4期569-573,共5页
Acta Ecologica Sinica
基金
中国科学院重点项目! ( KZ952 -J1 -2 0 2 )
中国科学院"陆地生态系统痕量物质生态过程"开放实验室和中国科学院百人计划"森林界面生
关键词
杉木人工林
连栽
细根
分泌
粮-土界面
生长
地力衰退
Chinese fir plantation
continuous cropping
fine-root
exudation, root-soil interface
