Standard litterbags underestimate early-stage lower-order root decomposition rate in a subtropical forest, China

2021 ◽  
Author(s):  
Guan-tao Chen ◽  
Yu-qin Chen ◽  
Yong Peng ◽  
Hong-ling Hu ◽  
Jiu-long Xie ◽  
...  
Keyword(s):  
Lower Order ◽  
Decomposition Rate ◽  
Early Stage ◽  
Subtropical Forest ◽  
Root Decomposition ◽  
Order Root

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

Forests ◽  
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.

Readjustment of Canadian Secondary Horizontal Control Networks

1978 ◽  
Vol 32 (4) ◽  
pp. 433-442
Author(s):  
C.D. McLellan ◽  
J.P. Henderson ◽  
J.D. Boal
Keyword(s):  
Least Squares ◽  
Approximate Method ◽  
Lower Order ◽  
Early Stage ◽  
Geodetic Survey ◽  
Secondary Control ◽  
Control Networks ◽  
Least Squares Adjustment ◽  
Secondary Networks ◽  
Horizontal Control

The readjustment of the Canadian secondary and lower order control networks is scheduled to take place in 1983 following the adoption of new primary framework values. Some 200 000 points are involved. 75 000 of which are the responsibility of the Geodetic Survey. These networks are to be evaluated, strengthened, densified and extended as necessary, prior to integration. The project will be done by regions defined, for the most part, by arcs of framework control. Secondary networks will be integrated with the framework by least squares adjustment; some lower order control may be recomputed by an approximate method. Considering the amount of secondary control to be readjusted, it is essential that agreement on the sharing of responsibilities between the federal and provincial agencies involved be reached at an early stage.

Effects of phosphorus addition on fine root decomposition and enzyme activity of Castanopsis carlesii and Cunninghamia lanceolata in subtropical forest

2017 ◽  
Vol 37 (1) ◽  
Author(s):  
洪慧滨 HONG Huibin ◽  
林成芳 LIN Chengfang ◽  
彭建勤 PENG Jianqin ◽  
陈岳民 CHEN Yuemin ◽  
魏翠翠 WEI Cuicui ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Fine Root ◽  
Subtropical Forest ◽  
Cunninghamia Lanceolata ◽  
Root Decomposition ◽  
Phosphorus Addition ◽  
Fine Root Decomposition

scholarly journals Contrasting dynamics and trait controls in first-order root compared with leaf litter decomposition

2018 ◽  
Vol 115 (41) ◽  
pp. 10392-10397 ◽  
Author(s):  
Tao Sun ◽  
Sarah E. Hobbie ◽  
Björn Berg ◽  
Hongguang Zhang ◽  
Qingkui Wang ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Arbuscular Mycorrhizal ◽  
Interspecific Variation ◽  
Root Decomposition ◽  
Control Mechanisms ◽  
First Order ◽  
C Cycle ◽  
Order Root ◽  
Dynamics And Control ◽  
Decomposition Models

Decomposition is a key component of the global carbon (C) cycle, yet current ecosystem C models do not adequately represent the contributions of plant roots and their mycorrhizae to this process. The understanding of decomposition dynamics and their control by traits is particularly limited for the most distal first-order roots. Here we followed decomposition of first-order roots and leaf litter from 35 woody plant species differing in mycorrhizal type over 6 years in a Chinese temperate forest. First-order roots decomposed more slowly (k = 0.11 ± 0.01 years−1) than did leaf litter (0.35 ± 0.02 years−1), losing only 35% of initial mass on average after 6 years of exposure in the field. In contrast to leaf litter, nonlignin root C chemistry (nonstructural carbohydrates, polyphenols) accounted for 82% of the large interspecific variation in first-order root decomposition. Leaf litter from ectomycorrhizal (EM) species decomposed more slowly than that from arbuscular mycorrhizal (AM) species, whereas first-order roots of EM species switched, after 2 years, from having slower to faster decomposition compared with those from AM species. The fundamentally different dynamics and control mechanisms of first-order root decomposition compared with those of leaf litter challenge current ecosystem C models, the recently suggested dichotomy between EM and AM plants, and the idea that common traits can predict decomposition across roots and leaves. Aspects of C chemistry unrelated to lignin or nitrogen, and not presently considered in decomposition models, controlled first-order root decomposition; thus, current paradigms of ecosystem C dynamics and model parameterization require revision.

Measurements of fine root decomposition rate: Method matters

2021 ◽  
pp. 108482
Author(s):  
Xuefeng Li ◽  
Xingbo Zheng ◽  
Quanlai Zhou ◽  
Steven McNulty ◽  
John S. King
Keyword(s):  
Decomposition Rate ◽  
Fine Root ◽  
Root Decomposition ◽  
Rate Method ◽  
Fine Root Decomposition

scholarly journals Early Stage Fine-Root Decomposition and Its Relationship with Root Order and Soil Depth in a Larix gmelinii Plantation

Forests ◽  
2016 ◽  
Vol 7 (12) ◽  
pp. 234 ◽  
Author(s):  
Tao Sun ◽  
Lili Dong ◽  
Lili Zhang ◽  
Zhijie Wu ◽  
Qingkui Wang ◽  
...  
Keyword(s):  
Fine Root ◽  
Early Stage ◽  
Soil Depth ◽  
Larix Gmelinii ◽  
Root Decomposition ◽  
Root Order ◽  
Fine Root Decomposition

Effects of long-term field experiments on early stage litter decomposition in Austria and Sweden

2020 ◽  
Author(s):  
Maria Regina Gmach ◽  
Martin A. Bolinder ◽  
Lorenzo Menichetti ◽  
Thomas Kätterer ◽  
Taru Sandén
Keyword(s):  
Litter Decomposition ◽  
Decomposition Rate ◽  
Field Experiments ◽  
Early Stage ◽  
Tillage Systems ◽  
K Value ◽  
Tea Bag Index ◽  
The Impact ◽  
Term Field

<p>Soil organic matter decomposition affects the local and global C cycles. Decomposition is mainly affected by soil type and climatic conditions, for a given quality of organic material. This study tested the effect of land use and management, litter type, and climate on the early stage decomposition rate in long-term field experiments (LTEs) in Austria and Sweden. Standardized litter (Rooibos and Green tea) were used according to the Tea Bag Index (TBI) protocol (Keuskamp et al. 2013) for comparison of litter decomposition rate (k) and stabilization factor (S) in 11 sites in Austria (2015 and 2016) and 9 sites in Sweden (2016). The tea bags were buried at 8 cm depth and collected after ~90 days. Austrian LTEs focused on mineral nitrogen fertilization, mineral potassium fertilization, organic fertilization, tillage systems, and crop residues management. The LTEs evaluated in Sweden focused mainly on annual and perennial crops, mineral fertilization, and tillage systems. The impact of environmental parameters (air temperature and precipitation) was modeled to normalize the variance due to climatic effects at each site. The preliminary results show that in Austria TBI decomposition differed more between sites than between treatments at the same LTE. Minimum tillage treatment had significantly higher decomposition rates compared to reduced and conventional tillage. In Sweden, decomposition rate differed more between treatments than between sites. Fertilized plots showed higher stabilization than unfertilized, and maximum N fertilization had the highest k, while unfertilized had the lowest k. The effect of different tillage systems on k and S were variable across sites and treatments, although ploughing tended to result in the lowest k. The northernmost site resulted in the highest k value. Results indicated higher stabilization in perennial forage crops compared to annual crops. We also considered time-series decomposition for some sites with measurements at different time points by the TBI approach (retrieving tea bags after 15, 30, 60, and 90 days), and the use of Random Forest regressions to evaluate the importance of pedo-climatic variables on early stage decomposition.</p>

scholarly journals Global-change effects on early-stage decomposition processes in tidal wetlands – implications from a global survey using standardized litter

2018 ◽  
Vol 15 (10) ◽  
pp. 3189-3202 ◽  
Author(s):  
Peter Mueller ◽  
Lisa M. Schile-Beers ◽  
Thomas J. Mozdzer ◽  
Gail L. Chmura ◽  
Thomas Dinter ◽  
...  
Keyword(s):  
Global Change ◽  
Sea Level ◽  
Decomposition Rate ◽  
Early Stage ◽  
High Sensitivity ◽  
Tidal Marshes ◽  
Tidal Wetlands ◽  
Coastal Eutrophication ◽  
Relative Sea Level ◽  
Effects Of Temperature

Abstract. Tidal wetlands, such as tidal marshes and mangroves, are hotspots for carbon sequestration. The preservation of organic matter (OM) is a critical process by which tidal wetlands exert influence over the global carbon cycle and at the same time gain elevation to keep pace with sea-level rise (SLR). The present study assessed the effects of temperature and relative sea level on the decomposition rate and stabilization of OM in tidal wetlands worldwide, utilizing commercially available standardized litter. While effects on decomposition rate per se were minor, we show strong negative effects of temperature and relative sea level on stabilization, as based on the fraction of labile, rapidly hydrolyzable OM that becomes stabilized during deployment. Across study sites, OM stabilization was 29 % lower in low, more frequently flooded vs. high, less frequently flooded zones. Stabilization declined by ∼ 75 % over the studied temperature gradient from 10.9 to 28.5 ∘C. Additionally, data from the Plum Island long-term ecological research site in Massachusetts, USA, show a pronounced reduction in OM stabilization by > 70 % in response to simulated coastal eutrophication, confirming the potentially high sensitivity of OM stabilization to global change. We therefore provide evidence that rising temperature, accelerated SLR, and coastal eutrophication may decrease the future capacity of tidal wetlands to sequester carbon by affecting the initial transformations of recent OM inputs to soil OM.

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