Biomass production and distribution of roots in three stands of Populus deltoides
Biomass production and distribution of roots in three stands of Populus deltoides
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DOI：
10.1016/0378-1127(94)90165-1
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发表时间：
1994-06
影响因子：
3.7
通讯作者：
S. Puri;Virendra Singh;B. Bhushan;S. Singh
中科院分区：
文献类型：
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作者：
S. Puri;Virendra Singh;B. Bhushan;S. Singh
农林业涉及将树木和作物搭配起来，使它们相互补充，有效分享现有资源，以实现最大生产力。因此，了解根系的生物量生产和分布具有相当大的实用价值。在哈里亚纳邦农业大学农田区，对9年生美洲黑杨（Populus deltoides）以2 m × 2 m、4 m × 4 m和6 m × 6 m的种植密度进行了地上、地下生物量及粗、细根分布的研究。在2 m × 2 m、4 m × 4 m和6 m × 6 m的林分中，密度分别为2250株/hm 2、531株/hm 2和208株/hm 2。总生物量（地上和地下）从71.50吨ha-1到251.50吨ha-1不等，具体取决于树木密度。在各组成部分中，干材生物量最大（66.3-71.3%），生物量大小顺序为干>根>枝>叶，粗根主要分布在土壤表层30 cm，细根主要集中在表层15 cm。粗根生物量随林距的增加而减少，从2 m × 2 m林分的29.8 t ha− 1减少到6 m × 6 m林分的5.6 t ha− 1。而细根生物量在2 m × 2 m和6 m × 6 m林分中分别从13.8 t ha− 1增加到23.0 t ha− 1，差异不显著（P> 0.05）。不同林分在距树行不同距离处的细根水平分布差异不显著。4 m × 4 m和6 m × 6 m林分的地下生物量基本相等，但前者的地上生物量是后者的2倍。地上部：根的比例随着间距的增加而下降。研究表明，杨树的大部分根系都在地表附近，因此可能与农作物存在根系竞争。
Agroforestry involves matching trees and crops so that they complement one another and share the available resources effectively in order to attain maximum productivity. A knowledge of biomass production and the distribution of root systems therefore has considerable practical value. Above ground and below ground biomass production and the distribution of coarse and fine roots were studied in 9-year-oldPopulus deltoides, planted at a spacing of 2 m × 2 m, 4 m × 4 m and 6 m × 6 m, in the farm area of Haryana Agricultural University, Hisar. The tree densities were 2250, 531 and 208 per hectare in the stands of 2 m × 2 m, 4 m × 4 m and 6 m × 6 m spacing, respectively. The total biomass (both above and below ground) varied from 71.50 tons ha−1to 251.50 tons ha−1, depending on the tree density. Among the different tree components, stemwood contributed the maximum biomass (66.3–71.3%), and the biomass was in the order of stem > root > branches > leaves.Patterns of root distribution showed that most of the coarse roots were distributed in the top 30 cm of soil, whereas fine roots were concentrated in the top 15 cm. Coarse root biomass decreased with an increase in spacing from 29.8 tons ha−1in the stand of 2 m × 2 m to 5.6 tons ha−1in the stand of 6 m × 6 m. In contrast fine root biomass increased significantly (P> 0.05) from 13.8 to 23.0 tons ha−1in the stands of 2 m × 2 m and 6 m × 6 m, respectively. No significant difference was observed in the horizontal distribution of fine roots at different distances from the tree rows at a particular depth in any of the stands. Total below ground biomass was equal in the stands of 4 m × 4 m and 6 m × 6 m, although the former had twice as much above ground biomass than the latter. The shoot: root ration decreased with an increase in spacing. The study indicates that the bulk of the roots of popular are found near the surface, and hence there may be root competition with agricultural crops.