植物生态学报 ›› 2013, Vol. 37 ›› Issue (10): 961-971.doi: 10.3724/SP.J.1258.2013.00099

• 研究论文 • 上一篇    下一篇

宽窄行栽植下三倍体毛白杨根系生物量分布及其对土壤养分因子的响应

邸楠1*, 席本野1*, Jeremiah R. PINTO2, 王烨1, 李广德3, 贾黎明1**   

  1. 1北京林业大学省部共建森林培育与保护教育部重点实验室, 北京 100083;
    2US Department of Agriculture, Forest Service, Rocky Mountain Research Station, 1221 S Main St, Moscow, ID 83843, USA;
    3中央广播电视大学农林医药学院, 北京 100039
  • 收稿日期:2013-03-19 修回日期:2013-07-15 出版日期:2013-10-01 发布日期:2013-09-29
  • 通讯作者: 贾黎明 E-mail:jlm@bjfu.edu.cn
  • 基金资助:

    国家林业公益性行业科研专项经费重大项目;大学生科研训练计划项目

Root biomass distribution of triploid Populus tomentosa under wide- and narrow-row spacing planting schemes and its responses to soil nutrients

DI Nan1*, XI Ben-Ye1*, Jeremiah R. PINTO2, WANG Ye1, LI Guang-De3, and JIA Li-Ming1**   

  1. 1Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China;

    2US Department of Agriculture, Forest Service, Rocky Mountain Research Station, 1221 S Main St, Moscow, ID 83843, USA;

    3Faculty of Agroforestry & Medicine, The Open University of China, Beijing 100039, China
  • Received:2013-03-19 Revised:2013-07-15 Online:2013-10-01 Published:2013-09-29
  • Contact: JIA Li-Ming E-mail:jlm@bjfu.edu.cn

摘要:

三倍体毛白杨(triploid Populus tomentosa)是我国华北地区主要纸浆林品种, 在该地区多采用宽窄行模式栽植。为基于根系结构特征制定该模式下毛白杨人工林高效水肥管理策略和明确影响其根系空间分布的主要因子, 在5年生林分中于8株样树周围挖取2 106个土柱, 研究该栽植模式下毛白杨根系生物量的空间分布特征, 并分析了细根垂直分布对土壤有机质、速效磷和碱解氮等的响应。结果表明, 一维垂向上, 宽行内细根根重密度(FRBD)在0–30 cm土层中随深度增加而递减, 但在30cm以下土层呈均匀分布(p = 0.079); 窄行内FRBD呈“双峰”分布, 即在0–20 cm (22%)和70–110 cm (31%)土层均有较多细根分布; 10–150 cm各土层中, 窄行FRBD较宽行高17%–148%。宽、窄行内, 随深度增加, 粗根根重密度(CRBD)均呈先增后减变化, 而细根粗根比(F/C)无显著变化(p > 0.05), 窄行平均F/C较宽行高60%。一维径向上, 宽、窄行内FRBD均呈近均匀分布, 而CRBD和F/C均随距离增加分别显著递减和增大。二维尺度上, FRBD在窄行内分布相对均匀, 但在宽行内主要集中在表土层且随距离增加细根浅层化程度增强; CRBD在树干两侧呈“不对称”分布; 垂向0–20 cm、径向160–300 cm范围是宽行内平均FRBD和F/C较高区域, 分别为宽行相应指标总平均的2.8和1.1倍。FRBD在0–30 cm土层中随土壤有机质、速效磷和碱解氮含量的增加而逐渐增大, 但在30 cm以下土层中无明显变化趋势。研究结果表明, 宽、窄行间毛白杨根系分布的差异性主要体现在细根一维垂直分布和细根、粗根二维分布上。土壤有机质、速效磷和碱解氮是0–30 cm土层中毛白杨细根垂直分布的重要影响因子, 但对下层土壤中根系分布无影响。对宽窄行栽植的毛白杨林分灌溉时, 灌溉水应供给到窄行区域; 施肥时, 缓释肥和速效
肥应分别浅施在宽行中央附近和窄行内。

Abstract:
Aims Triploid Populus tomentosa, a main clone for pulpwood forestry in the North China Plain, is usually planted using a wide- and narrow-row spacing planting schemes (WNRPS). Our objectives were to make water and fertilizer management recommendations for P. tomentosa under a WNRPS based on root form characteristics, and determine the relationship between the vertical distribution of P. tomentosa fine roots (FR) and soil nutrient factors.
Methods We obtained 2 106 soil samples by soil coring down to 150 cm depth around eight sample trees in a five-year-old P. tomentosa plantation located in Gaotang County, Shandong Province, China. The samples were used to measure root distribution, organic matter (OM), available P and alkaline N content.
Important findings FR biomass density (FRBD) in the wide row zone (WRZ) decreased with increasing depth in the 0–30 cm soil, but was distributed evenly below 30 cm depth (p = 0.079). The vertical FRBD profile in the narrow row zone (NRZ) showed a bimodal pattern. In different layers at 10–150 cm depth, FRBD in the NRZ was 17%–148% higher than in the WRZ. With increasing depth in both WRZ and NRZ, coarse root biomass density (CRBD) increased and then decreased. However, the FRBD to CRBD ratio (F/C) varied slightly with depth (p > 0.05), and the mean F/C in the NRZ was 60% higher than that in the WRZ. Horizontally, in both WRZ and NRZ, the FRBD distribution was almost even, while the CRBD and F/C decreased and increased, respectively, with increasing distance from the trunk. On a two dimensional scale, the FRBD distribution within the NRZ was relatively even, but FR were mainly concentrated in surface soil within the WRZ. CRBD was distributed asymmetrically around the trunk. The ranges of 0–20 cm depth and 160–300 cm distance from the tree were the areas with high mean FRBD and F/C in the WRZ, which were 1.8 and 0.1 times larger than the mean values of corresponding variables in the WRZ, respectively. FRBD scaled positively with OM, available P and alkaline N content at 0–30 cm depth, but showed no obvious trend with respect to soil characteristics below 30 cm depth. In conclusion, the differences in P. tomentosa root distribution between WRZ and NRZ were reflected in the one- dimensional vertical FR distribution and two-dimensional FR and course roots distribution. OM, available P and alkaline N were key controls on the vertical FR distribution at 0–30 cm depth, but had no effects on FR distribution below 30 cm depth. For P. tomentosa plantations under WNRPS, water should be provided mainly to the NRZ, and slowand fast-release fertilizer should be supplied to the shallow soil in the area near the wide row center and in the NRZ, respectively.