Responses of fine roots to experimental nitrogen addition in a tropical lower montane rain forest, Panama

2010 ◽  
Vol 27 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Markus Adamek ◽  
Marife D. Corre ◽  
Dirk Hölscher
Keyword(s):  
Rain Forest ◽  
Root Biomass ◽  
Fine Root ◽  
Mineral Soil ◽  
N Fertilization ◽  
Fine Root Biomass ◽  
Organic Layer ◽  
N Addition ◽  
Ingrowth Cores ◽  
Montane Rain Forest

Abstract:Nitrogen (N) availability is a major control on fine-root growth and distribution with depth in forest soils. We investigated fine-root dynamics in response to N addition in a montane rain forest with N-limited above-ground production. Control and N-fertilized (125 kg urea-N ha−1 y−1) treatments were laid out in a paired-plot design with four replicates (each 40 × 40 m). During 1.5 y of treatment, fine root-biomass, necromass and production were assessed by sequential coring at three soil depths (organic layer, 0–10 cm and 10–20 cm mineral soil), whereas fine-root redistribution with depth was assessed by ingrowth cores. Total fine-root biomass, necromass and production in the controls were 458 ± 21 g m−2, 101 ± 9 g m−2 and 324 ± 33 g m−2 y−1, respectively. No significant difference at any depth was detected under N fertilization. Fine-root biomass in the organic layer decreased over time under N addition. At 10–20 cm in the mineral soil, fine-root biomass in ingrowth cores increased significantly after 1.5 y of N fertilization compared with the control. The increased available N may have induced the change in fine-root distribution to explore the deeper mineral soil for other nutrients which may cause additional limitation to above-ground production once N limitation is alleviated.

scholarly journals Effects of Elevated CO2 Concentration and Nitrogen Addition on Soil Respiration in a Cd-Contaminated Experimental Forest Microcosm

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 260
Author(s):  
Bo Yao ◽  
Qiwu Hu ◽  
Guihua Zhang ◽  
Yafeng Yi ◽  
Meijuan Xiao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Soil Respiration ◽  
Soil Carbon ◽  
Elevated Co2 ◽  
Root Biomass ◽  
Fine Root ◽  
Hydrolytic Enzymes ◽  
N Deposition ◽  
Fine Root Biomass ◽  
N Addition

Forests near rapidly industrialized and urbanized regions are often exposed to elevated CO2, increased N deposition, and heavy metal pollution. To date, the effects of elevated CO2 and/or increased N deposition on soil respiration (Rs) under heavy metal contamination are unclear. In this study, we firstly investigated Rs in Cd-contaminated model forests with CO2 enrichment and N addition in subtropical China. Results showed that Rs in all treatments exhibited similar clear seasonal patterns, with soil temperature being a dominant control. Cadmium addition significantly decreased cumulative soil CO2 efflux by 19% compared to the control. The inhibition of Rs caused by Cd addition was increased by N addition (decreased by 34%) was partially offset by elevated CO2 (decreased by 15%), and was not significantly altered by the combined N addition and rising CO2. Soil pH, microbial biomass carbon, carbon-degrading hydrolytic enzymes, and fine root biomass were also significantly altered by the treatments. A structural equation model revealed that the responses of Rs to Cd stress, elevated CO2, and N addition were mainly mediated by soil carbon-degrading hydrolytic enzymes and fine root biomass. Overall, our findings indicate that N deposition may exacerbate the negative effect of Cd on Rs in Cd-contaminated forests and benefit soil carbon sequestration in the future at increasing atmospheric CO2 levels.

scholarly journals Quantity and distribution of fine root biomass in the intermediate stage of beech virgin forest Badínsky prales

2009 ◽  
Vol 55 (No. 11) ◽  
pp. 502-510 ◽  
Author(s):  
P. Jaloviar ◽  
L. Bakošová ◽  
S. Kucbel ◽  
J. Vencurik
Keyword(s):  
Root Length ◽  
Root Biomass ◽  
Fine Root ◽  
Soil Depth ◽  
Mineral Soil ◽  
Soil Layer ◽  
Intermediate Stage ◽  
Fine Root Biomass ◽  
Virgin Forest ◽  
Fine Root Length

The fine root biomass represents 3,372 kg/ha in the intermediate stage of the beech virgin forest with different admixture of goat willow, where the vast majority of this biomass is located in the uppermost mineral soil layer 0–10 cm. The variability of the fine root biomass calculated from 35 sample points represents approximately 90% of the mean value and reaches the highest value within the humus layer. The total fine root length investigated in 10 cm thick soil layers decreases with increasing soil depth. A significant linear relationship between the fine root length (calculated per 1 cm thick soil layer and 1 m<sup>2</sup> of stand area) and the soil depth was confirmed, although the correlation is rather weak. The number of root tips decreases with increasing soil depth faster than the root length. As the number of tips per 1 cm of root length remains in the finest diameter class without significant changes, the reason is above all a decreased proportion of the finest root class (diameter up to 0.5 mm) from the total fine root length within the particular soil layer.

scholarly journals Contrasting Root System Structure and Belowground Interactions between Black Spruce (Picea mariana (Mill.) B.S.P) and Trembling Aspen (Populus tremuloides Michx) in Boreal Mixedwoods of Eastern Canada

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 127 ◽  
Author(s):  
Claudele Ghotsa Mekontchou ◽  
Daniel Houle ◽  
Yves Bergeron ◽  
Igor Drobyshev
Keyword(s):  
Nutrient Uptake ◽  
Resource Use ◽  
Root Biomass ◽  
Competitive Exclusion ◽  
Fine Root ◽  
Black Spruce ◽  
Mineral Soil ◽  
Organic Layer ◽  
Mixed Stands ◽  
Boreal Mixedwoods

This study explored the underground interactions between black spruce and trembling aspen in pure and mixed stands to understand how their soil resource use help these species coexist in the boreal mixedwoods of Western Quebec. We analyzed species-specific fine root foraging strategies (root biomass and root tissue density) along three soil layers (organic, top 0–15 cm, and bottom 15–30 cm mineral soil), using 180 soil cores. We collected cores in three sites, each containing three 20 × 50 m2 plots of pure spruce, pure aspen, and mixed spruce and aspen stands. Spruce had a shallow rooting, whereas aspen had a deep rooting in both types of stands. Compared to pure spruce stands, spruce had a lower fine root biomass (FRB) and a higher root tissue density (RTD) in the organic layer of mixed stands. Both patterns were indicative of spruce’s more intensive resource use strategy and competitive advantage over aspen in that layer. Aspen FRB in the organic soil did not differ significantly between pure and mixed stands, but increased in the mineral soil of mixed stands. Since we did not observe a significant difference in the nutrient content of the mineral soil layer between pure aspen and mixed stands, we concluded that aspen may experience competitive exclusion in the organic layer by spruce. Aspen exhibited an extensive nutrient uptake strategy in the organic layer of mixed stands: higher FRB and lower RTD than spruce. In mixed stands, the differences in aspen rooting patterns between the organic and mineral layers suggested the use of contrasting nutrient uptake strategies along the soil profile. We speculate that the stronger spatial separation of the roots of spruce and aspen in mixed stands likely contribute to a higher partitioning of their nutrient uptake along the soil profile. These results indicate the competitive exclusion of aspen by spruce in boreal mixedwoods, which likely occurs in the soil organic layer.

Early effect of elevated nitrogen input on above-ground net primary production of a lower montane rain forest, Panama

2009 ◽  
Vol 25 (6) ◽  
pp. 637-647 ◽  
Author(s):  
Markus Adamek ◽  
Marife D. Corre ◽  
Dirk Hölscher
Keyword(s):  
Primary Production ◽  
Rain Forest ◽  
Net Primary Production ◽  
Woody Biomass ◽  
N Fertilization ◽  
Stem Growth ◽  
First Year ◽  
N Addition ◽  
Montane Rain Forest ◽  
Stem Diameter Growth

Abstract:To evaluate N limitation on above-ground net primary production in a tropical lower montane rain forest, an N fertilization experiment was conducted for 2 y. The study site is located at 1200–1300 m asl in the Fortuna forest reserve in western Panama and has a mature, mixed-species stand growing on an Andisol soil. Control and N-fertilized (125 kg urea-N ha−1 y−1) treatments were represented by four replicate plots (each 40 × 40 m, separated by at least 40 m). Stem diameter growth was analysed by diameter at breast height classes and also for the three most abundant species. The three species did not respond to N addition. The response of stem growth and above-ground woody biomass production to N fertilization varied among dbh classes. Stem growth of trees of 10–30 cm dbh increased only in the first year of N addition while trees of 30–50 cm dbh responded in the second year of N addition, which may be due to differences in light conditions between years. Trees >50 cm dbh did not respond during 2 years of N addition. As a result, the overall stem growth and above-ground woody biomass production were not affected by N fertilization. Annual total fine litterfall increased in the first year of N fertilization, while annual leaf litterfall increased in both years of N addition. Above-ground net primary production, of which total fine litterfall constituted 68%, also increased only in the first year of N addition. The magnitude and timing of response of stem diameter growth and litterfall suggest that these aspects of above-ground productivity are not uniformly limited by N availability.

Plasticity of Pine Tree Roots to Podzolization of Boreal Sandy Soils

2021 ◽  
Author(s):  
Kazumichi Fujii ◽  
Naoki Makita ◽  
Martin Küttim ◽  
Kamara Mouctar ◽  
Sugita Shinya
Keyword(s):  
Boreal Forests ◽  
Root Biomass ◽  
Morphological Traits ◽  
Depth Distribution ◽  
Fine Root ◽  
Mineral Soil ◽  
Fine Root Biomass ◽  
Nutrient Loss ◽  
P Availability ◽  
Fe Oxides

Abstract Aims The morphological traits of fine roots change with forest succession and soil weathering. However, low tree species diversity in boreal forests may limit plastic responses of the roots to soil nutrient loss. We tested whether pine trees (Pinus sylvestris L.) have root plasticity to change fine root allocation to deeper soil horizons in response to varying degree of podzolization. Methods We compared root biomass in two sand dune chronosequences (aluminium (Al)/iron (Fe) oxide-poor coarse-textured sand vs. oxide-rich fine-textured sand) in Estonia. Results We found that faster podzolization in coarse-textured soil promotes migration of Al/Fe oxides and phosphorus (P) into deeper horizons and reshapes the depth distribution of fine root biomass. A decrease in P availability in the coarse-textured soil profile increases fine root biomass and length in both the organic and mineral horizons. In the fine-textured old soil, fine root distribution increases in the mineral soil (especially, spodic horizon) rich in oxide-bonded P.Conclusion Pine roots have two plasticities in low-diversity boreal forests – changing root morphological traits and changing depth distribution of root biomass, depending on the abundance of Al and Fe oxides and the depth distribution and dominant form of P.

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