Effect of Root and Mycelia on Fine Root Decomposition and Release of Carbon and Nitrogen Under Artemisia halodendron in a Semi-arid Sandy Grassland in China

Plant fine root turnover is a continuous process both spatially and temporally, and fine root decomposition is affected by many biotic and abiotic factors. However, the effect of the living roots and the associated mycorrhizal fungal mycelia on fine root decomposition remains unclear. The objective of this study is to explore the influence of these biotic factors on fine root decomposition in a semi-arid ecosystem. In this study, we investigated the effect of fine roots and mycelia on fine root decomposition of a pioneer shrub (Artemisia halodendron) in Horqin sandy land, northeast China, by the ingrowth core method combined with the litterbag method. Litterbags were installed in cores. Results showed that core a allowed the growth of both fine roots and mycelia (treatment R + M), core b only allowed the growth of mycelia (treatment M), and in core c the fine root and mycelia growth were restricted and only bulk soil was present (treatment S). These findings suggest that the process of root decomposition was significantly affected by the living roots and mycelia, and carbon (C) and nitrogen (N) concentration dynamics during root decomposition differed among treatments. Mycelia significantly stimulated the mass loss and C and N release during root decomposition. Treatment R + M significantly stimulated the accumulation of soil total C, total N, and organic N under litterbags. The mycelia significantly stimulated the accumulation of the inorganic N (ammonium-N and nitrate-N) but the presence of fine roots weakened nitrate-N accumulation. The presence of living roots and associated mycelia strongly affected the process of root decomposition and matter release in the litter-soil system. The results of this study should strengthen the understanding of root-soil interactions.

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An improved method for quantifying total fine root decomposition in plantation forests combining measurements of soil coring and minirhizotrons with a mass balance model

Tree Physiology ◽

10.1093/treephys/tpaa074 ◽

2020 ◽

Vol 40 (10) ◽

pp. 1466-1473

Author(s):

Xuefeng Li ◽

Kevan J Minick ◽

Tonghua Li ◽

James C Williamson ◽

Michael Gavazzi ◽

...

Keyword(s):

Fine Roots ◽

Root Biomass ◽

Turnover Rate ◽

Fine Root ◽

Fine Root Biomass ◽

Balance Model ◽

Root Decomposition ◽

Mass Balance Model ◽

Monthly Total ◽

Fine Root Decomposition

Abstract Accurate measurement of total fine root decomposition (the amount of dead fine roots decomposed per unit soil volume) is essential for constructing a soil carbon budget. However, the ingrowth/soil core-based models are dependent on the assumptions that fine roots in litterbags/intact cores have the same relative decomposition rate as those in intact soils and that fine root growth and death rates remain constant over time, while minirhizotrons cannot quantify the total fine root decomposition. To improve the accuracy of estimates for total fine root decomposition, we propose a new method (balanced hybrid) with two models that integrate measurements of soil coring and minirhizotrons into a mass balance model. Model input parameters were fine root biomass, necromass and turnover rate for Model 1, and fine root biomass, necromass and death rate for Model 2. We tested the balanced hybrid method in a loblolly pine plantation forest in coastal North Carolina, USA. The total decomposition rate of absorptive fine roots (ARs) (a combination of first- and second-order fine roots) using Models 1 and 2 was 107 ± 13 g m−2 year−1 and 129 ± 12 g m−2 year−1, respectively. Monthly total AR decomposition was highest from August to November, which corresponded with the highest monthly total ARs mortality. The ARs imaged by minirhizotrons well represent those growing in intact soils, evident by a significant and positive relationship between the standing biomass and the standing length. The total decomposition estimate in both models was sensitive to changes in fine root biomass, turnover rate and death rate but not to change in necromass. Compared with Model 2, Model 1 can avoid the technical difficulty of deciding dead time of individual fine roots but requires greater time and effort to accurately measure fine root biomass dynamics. The balanced hybrid method is an improved technique for measuring total fine root decomposition in plantation forests in which the estimates are based on empirical data from soil coring and minirhizotrons, moving beyond assumptions of traditional approaches.

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Contributions of fine root production and turnover to the carbon and nitrogen cycling in taiga forests of the Alaskan interior

Canadian Journal of Forest Research ◽

10.1139/x26-148 ◽

1996 ◽

Vol 26 (8) ◽

pp. 1326-1336 ◽

Cited By ~ 159

Author(s):

R.W. Ruess ◽

K. Van Cleve ◽

J. Yarie ◽

L.A. Viereck

Keyword(s):

Fine Roots ◽

Fine Root ◽

Organic N ◽

Root Turnover ◽

Root Production ◽

Total Production ◽

Fine Root Production ◽

Litter Fall ◽

Fine Root Turnover ◽

Taiga Forests

Fine root production and turnover were studied in hardwood and coniferous taiga forests using three methods. (1) Using soil cores, fine root production ranged from 1574 ± 76 kg•ha−1•year−1 in the upland white spruce (Piceaglauca (Moench) Voss) stand to 4386 ± 322 kg•ha−1•year−1 in the floodplain balsam poplar (Populusbalsamifera L.) stand, accounting for 49% of total production for coniferous stands and 32% of total production for deciduous stands. Fine root turnover rates were higher in floodplain (0.90 ± 0.06 year−1) stands than in upland (0.42 ± 0.10 year−1) stands. Across all sites, the ratio of fine root turnover to litter fall averaged 2.2 for biomass and 2.8 for N. Both values were higher in floodplain stands than in upland stands, and in coniferous stands than in deciduous stands. (2) The C budget method showed that C allocation to fine roots varied from 150 to 425 g C•m−2•year−1 and suggested that soil respiration was more dependent on C derived from roots than from aboveground inputs. The C allocation ratio (C to roots: C to litter fall) was inversely correlated with litter-fall C and varied from 0.3 to 69.5; there was a tendency for higher proportional belowground allocation in coniferous stands than in deciduous stands and the highest levels were at the earliest successional sites. (3) Estimates of apparent N uptake (Nu), N allocation to fine roots, and fine root production based on N budget calculations showed that annual aboveground N increments exceeded Nu estimates at half the sites, indicating that the method failed to account for large amounts of N acquired by plants. This suggests that plant and (or) mycorrhizal uptake of soil organic N may be more significant to ecosystem N cycling than mineral N turnover by the soil microbial biomass.

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Fine-root decomposition and N dynamics in coniferous forests of the Pacific Northwest, U.S.A.

Canadian Journal of Forest Research ◽

10.1139/x01-202 ◽

2002 ◽

Vol 32 (2) ◽

pp. 320-331 ◽

Cited By ~ 75

Author(s):

Hua Chen ◽

Mark E Harmon ◽

Jay Sexton ◽

Becky Fasth

Keyword(s):

Pacific Northwest ◽

Fine Roots ◽

Fine Root ◽

Root Decomposition ◽

N Availability ◽

Soil N ◽

Decomposition Rates ◽

N Dynamics ◽

The Pacific ◽

Fine Root Decomposition

We examined the effects of species, initial substrate quality, and site differences (including temperature, precipitation, and soil N availability) on fine-root (<2 mm diameter) decomposition in litter bags and its N dynamics in Sitka spruce (Picea sitchensis (Bong) Carrière), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) forests in Oregon, U.S.A. Species significantly influenced fine-root mass loss during the first 2 years of decomposition. Over the same period, site differences had little impact on decomposition of fine roots. The percentage of initial mass remaining of decomposing fine roots fitted a single-exponential model. The decomposition rate constant (k) for all 15 species examined ranged from 0.172 year1 for Engelmann spruce (Picea engelmanni Parry ex Engelm.) to 0.386 year1 for Oregon ash (Fraxinus latifolia Benth.). Initial C quality indices (e.g., cellulose concentration, lignin concentration) of fine roots were correlated with fine-root decomposition rates. In contrast, initial N concentration and soil N availability were not correlated with fine-root decomposition rates. The rate of N released from decomposing roots was positively correlated with the initial N concentration of the fine roots. The data suggest that decomposing fine roots could release at least 20 kg N/ha annually in mature Douglas-fir forests of the Pacific Northwest.

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Heterogeneity in Decomposition Rates and Nutrient Release in Fine-Root Architecture of Pinus massoniana in the Three Gorges Reservoir Area

Forests ◽

10.3390/f11010014 ◽

2019 ◽

Vol 11 (1) ◽

pp. 14

Author(s):

Shao Yang ◽

Ruimei Cheng ◽

Wenfa Xiao ◽

Yafei Shen ◽

Lijun Wang ◽

...

Keyword(s):

Lower Order ◽

Fine Root ◽

C:N Ratio ◽

Pinus Massoniana ◽

Higher Order ◽

Root Decomposition ◽

Decomposition Rates ◽

N Release ◽

Residual N ◽

Fine Root Decomposition

Fine-root decomposition contributes a substantial amount of nitrogen that sustains both plant productivity and soil metabolism, given the high turnover rates and short root life spans of fine roots. Fine-root decomposition and soil carbon and nitrogen cycling were investigated in a 1-year field litterbag study on lower-order roots (1–2 and 3–4) of Pinus massoniana to understand the mechanisms of heterogeneity in decomposition rates and further provide a scientific basis for short-time research on fine-root decomposition and nutrient cycling. Lower-order roots had slower decay rates compared with higher-order roots (5–6). A significantly negative correlation was observed between the decay constant mass remaining and initial N concentrations as well as acid unhydrolyzable residues. Results also showed that in lower-order roots (orders 1–2 and 3–4) with a lower C:N ratio, root residual N was released and then immobilized, whereas in higher-order roots (order 5–6) with a higher C:N ratio, root residual N was immobilized and then released in the initial stage. In the later stage, N immobilization occurred in lower-order roots and N release in higher-order roots, with the C:N ratio gradually decreasing to about 40 in three branching-order classes and then increasing. Our results suggest that lower-order roots decompose more slowly than higher-order roots, which may result from the combined effects of high initial N concentration and poor C quality in lower-order roots. During the decomposition of P. massoniana, N release or N immobilization occurred at the critical C:N ratio.

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Global patterns in fine root decomposition: climate, chemistry, mycorrhizal association and woodiness

Ecology Letters ◽

10.1111/ele.13248 ◽

2019 ◽

Vol 22 (6) ◽

pp. 946-953 ◽

Cited By ~ 25

Author(s):

Craig R. See ◽

Michael Luke McCormack ◽

Sarah E. Hobbie ◽

Habacuc Flores‐Moreno ◽

Whendee L. Silver ◽

...

Keyword(s):

Fine Root ◽

Root Decomposition ◽

Mycorrhizal Association ◽

Global Patterns ◽

Fine Root Decomposition

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Differences in fine root traits between Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.) – A case study in the Kysucké Beskydy Mts

Journal of Forest Science ◽

10.17221/10/2009-jfs ◽

2009 ◽

Vol 55 (No. 12) ◽

pp. 556-566 ◽

Cited By ~ 7

Author(s):

B. Konôpka

Keyword(s):

Picea Abies ◽

Norway Spruce ◽

Fagus Sylvatica ◽

Seasonal Dynamics ◽

Fine Roots ◽

Fine Root ◽

Root Traits ◽

European Beech ◽

Root Turnover ◽

Mortality Ratio

Interspecific comparisons of the fine root “behaviour” under stressful situations may answer questions related to resistance to changing environmental conditions in the particular tree species. Our study was focused on Norway spruce (<I>Picea abies</I> [L.] Karst.) and European beech (<I>Fagus sylvatica</I> L.) grown in an acidic soil where acidity was caused by past air pollution in the Kysucké Beskydy Mts., North-Western Slovakia. Between April and October 2006, the following fine root traits were studied: biomass and necromass seasonal dynamics, vertical distribution, production, mortality, fine root turnover and production to mortality ratio. Sequential soil coring was repeatedly implemented in April, June, July, September, and October including the soil layers of 0–5, 5–15, 15–25, and 25–35 cm. Results indicated that spruce had a lower standing stock of fine roots than beech, and fine roots of spruce were more superficially distributed than those of beech. Furthermore, we estimated higher seasonal dynamics and also higher turnover of fine roots in spruce than in beech. The production to mortality ratio was higher in beech than in spruce, which was hypothetically explained as the effect of drought episodes that occurred in July and August. The results suggested that the beech root system could resist a physiological stress better than that of spruce. This conclusion was supported by different vertical distributions of fine roots in spruce and beech stands.

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Fine Root Decomposition and Cycling of Cu, Ni, Pb, and Zn at Forest Sites Near Smelters in Sudbury, ON, and Rouyn-Noranda, QU, Canada

Human and Ecological Risk Assessment An International Journal ◽

10.1080/10807030701790447 ◽

2008 ◽

Vol 14 (1) ◽

pp. 41-53 ◽

Cited By ~ 4

Author(s):

Dallas Johnson ◽

Beverley Hale

Keyword(s):

Fine Root ◽

Root Decomposition ◽

Forest Sites ◽

Fine Root Decomposition

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Fine root decomposition, nutrient mobilization and fungal communities in a pine forest ecosystem

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2015.01.019 ◽

2015 ◽

Vol 83 ◽

pp. 76-83 ◽

Cited By ~ 28

Author(s):

Ang Li ◽

Timothy J. Fahey ◽

Teresa E. Pawlowska ◽

Melany C. Fisk ◽

James Burtis

Keyword(s):

Forest Ecosystem ◽

Fine Root ◽

Pine Forest ◽

Fungal Communities ◽

Root Decomposition ◽

Nutrient Mobilization ◽

Fine Root Decomposition

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Effect of thinning on production and mortality of fine roots in a Pinusradiata plantation on a fertile site in New Zealand

Canadian Journal of Forest Research ◽

10.1139/x87-144 ◽

1987 ◽

Vol 17 (8) ◽

pp. 919-928 ◽

Cited By ~ 61

Author(s):

D. Santantonio ◽

E. Santantonio

Keyword(s):

Fine Roots ◽

Standing Crop ◽

Fine Root ◽

General Pattern ◽

Minor Component ◽

Root Decomposition ◽

Root Production ◽

Soil Core ◽

Stem Wood ◽

Small Roots

The effects of heavy thinning (60% reduction in basal area) on fine (< 1 mm diam.) and small roots (1–5 mm diam.) were evaluated during the 2nd year following treatment by periodic soil core sampling in a 12-year-old plantation of Pinusradiata D. Don. Data from these samples enabled us to estimate monthly standing crops of live and dead fine roots and seasonal rates of fine-root decomposition. We used a compartment-flow model to estimate production and mortality of fine roots with monthly resolution from these data. The general pattern of production and mortality was modal and out of phase with soil temperature. On an area basis, thinning reduced the overall standing crop of live fine roots from 1.38 to 0.55 Mg/ha; the standing crop of dead fine roots remained unchanged at 4.37 Mg/ha. The standing crop of live small roots declined from 1.03 to 0.54 Mg/ha. Annual production of fine roots was estimated at 2.2 and 1.9 Mg•ha−1•year−1 in the control and thinned treatment, respectively, and mortality was estimated at 2.1 and 2.0 Mg•ha−1•ear−1 in the control and thinned treatment, respectively. Thinning shortened mean fine-root longevity from 6.2 to 2.5 months. With respect to total dry matter production, fine-root production remained a minor component following a heavy thinning. It accounted for only 4.6 and 6.1% of the stand total in the control and thinned treatments, respectively. These results indicate that on a fertile site with a mild climate the opportunity to shift production from fine roots to another component, such as stem wood, is likely to be small.

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