scholarly journals Impacts of mixed-grazing on root biomass and belowground net primary production in a temperate desert steppe

2019 ◽  
Vol 6 (2) ◽  
pp. 180890 ◽  
Author(s):  
Zhanyi Wang ◽  
Jing Jin ◽  
Yanan Zhang ◽  
Xiaojuan Liu ◽  
Yongling Jin ◽  
...  
Keyword(s):  
Primary Production ◽  
Root Biomass ◽  
Net Primary Production ◽  
Single Species ◽  
Community Diversity ◽  
Root Turnover ◽  
Turnover Rates ◽  
Large Herbivores ◽  
Growing Seasons ◽  
Belowground Net Primary Production

The impacts of large herbivores on plant communities differ depending on the plants and the herbivores. Few studies have explored how herbivores influence root biomass. Root growth of vegetation was studied in the field with four treatments: sheep grazing alone (SG), cattle grazing alone (CG), mixed grazing with cattle and sheep (MG) and no grazing (CK). Live and total root biomasses were measured using the root ingrowth core and the drilling core, respectively. After 2 years of grazing, total root biomass showed a decreasing trend while live root biomass increased with time during the growing seasons. Belowground net primary production (BNPP) among the treatments varied from 166 ± 32 to 501 ± 88 g m −2 and root turnover rates (RTR) varied from 0.25 ± 0.05 to 0.70 ± 0.11 year −1 . SG had the greatest BNPP and RTR, while the CG had the smallest BNPP and RTR. BNPP and RTR of the MG treatment were between those of the CG and SG treatments. BNPP and RTR of the CK were similar to MG treatment. Compared with other treatments, CG had a greater impact on dominant tall grasses species in communities. SG could decrease community diversity. MG eliminated the disadvantages of single-species grazing and was beneficial to community diversity and stability.

scholarly journals Depth distribution of belowground net primary production across global biomes

2021 ◽  
Author(s):  
Zhongkui Luo ◽  
Guocheng Wang ◽  
Liujun Xiao ◽  
Xiali Mao ◽  
Xiaowei Guo ◽  
...  
Keyword(s):  
Primary Production ◽  
Depth Distribution ◽  
Net Primary Production ◽  
Soil Depth ◽  
Soil Layer ◽  
Soil Nutrient ◽  
Data Sets ◽  
Large Variability ◽  
Belowground Carbon ◽  
Belowground Net Primary Production

Abstract The depth distribution of belowground net primary production (BNPP) has been unquantified globally, hindering our understanding of belowground carbon dynamics. We synthesize global observational data sets to infer the depth allocation of BNPP down to 2 m, and map depth-specific BNPP globally at 1 km resolution. We estimate that global average BNPP in the 0–20 soil layer is 1.1 Mg C ha–1 yr–1, accounting for >50% of total BNPP. Across the globe, the depth distribution of BNPP shows large variability, and more BNPP is allocated to deeper layers in hotter and drier regions. Edaphic, climatic and topographic properties (in the order of importance) can explain >80% of such variability in different soil depths; and the direction and magnitude of the influence of individual properties (e.g., precipitation and soil nutrient) are soil depth- and biome-dependent. Our results provide global benchmarks for predictions of whole-soil carbon profiles across global biomes.

Organic matter dynamics of fine roots in plantations of slash pine (Pinuselliottii) in north Florida

1986 ◽  
Vol 16 (3) ◽  
pp. 529-538 ◽  
Author(s):  
Henry L. Gholz ◽  
Laurel C. Hendry ◽  
Wendell P. Cropper Jr.
Keyword(s):  
Organic Matter ◽  
Boreal Forests ◽  
Fine Roots ◽  
Root Biomass ◽  
Root Diameter ◽  
Slash Pine ◽  
Root Turnover ◽  
Root Production ◽  
Seasonal Patterns ◽  
Turnover Rates

Seasonal patterns of live, dead, and unknown viability fine (diameter, ≤10 mm) roots of pine and other vegetation in a young and old slash pine stand were sampled using monthly soil coring over a 24-month period. A distinct unimodal pattern for roots <1 mm in diameter in the surface soil was observed. Live roots increased in the spring to a peak in midsummer and then declined. Larger roots and roots deeper in the soil showed less distinct seasonal patterns, although maximum and minimum annual biomass values were sometimes significantly different. Decomposition of fine roots in buried mesh bags averaged 15–20% per year for roots <5 mm in diameter. An analysis of seasonal dynamics and decompositon rates were combined to construct organic matter budgets for the forest floor and soil. Estimated net root production for roots ≤10 mm in diameter was 590 and 626 g m−2 year−1 in the young and old stand, respectively. Root turnover contributed 214 and 452 g m−2 year−1 to detrital pools on the two sites, with the balance of production accumulating as standing root biomass or lost in decomposition. Root production and turnover rates decreased with increasing root diameter; most production was from roots <1 mm. Pine root production was greater and nonpine production was less in the older stand than in the younger stand. Compared with other temperate and boreal forests, root biomass was high and net root production relatively low. The low production:biomass ratio may be characteristic of low latitude (warm) and (or) low nutrient forest types.

Tolerance of the arctic graminoid Luzula arcuata ssp. confusa to simulated grazing in two nitrogen environments

2000 ◽  
Vol 78 (8) ◽  
pp. 1108-1113 ◽  
Author(s):  
Kari Anne Bråthen ◽  
Ann Marie Odasz-Albrigtsen
Keyword(s):  
Primary Production ◽  
No Reduction ◽  
Reproduction Number ◽  
Plant Traits ◽  
Net Primary Production ◽  
The Arctic ◽  
Growing Seasons ◽  
Simulated Grazing ◽  
Nitrogen Treatment ◽  
Low Nitrogen

We investigated the response of the important forage plant Luzula arcuata Swartz ssp. confusa (Lindeb.) Blytt to simulated grazing during two growing seasons in a phytotron. Plants were clipped at five levels of intensity and fertilized at two levels of nitrogen. There was no reduction in net primary production of clipped compared with unclipped plants after either of the two growing seasons. Such results indicate that L. arcuata ssp. confusa can compensate for defoliation. Plants overcompensated in net aboveground primary production (NAPP) in the first season and compensated in NAPP in the second season. Plant traits contributing to the compensation in NAPP were stimulation of tillering in clipped plants, increase in specific leaf area of the most heavily clipped plants, and a higher proportion of NAPP occurring below clipping height in frequently clipped plants. Sexual reproduction (number of flowering shoots) was enhanced in the second season in plants clipped at 6 cm above the soil and reduced in plants clipped 3 cm above the soil. The response to clipping was independent of nitrogen treatment, suggesting that nitrogen did not limit regrowth even in the low nitrogen environment. Luzula arcuata ssp. confusa is tolerant of dry, cold and windswept, low-nutrient habitats in the Arctic. This study shows that it also is tolerant of defoliation.Key words: forage, herbivory, compensation, grazing responses, Svalbard.

The primary production of aldabra atoll, with reference to habitats used by Giant Tortoises

1983 ◽  
Vol 302 (1109) ◽  
pp. 167-199 ◽  
Keyword(s):  
Primary Production ◽  
Standing Crop ◽  
Single Species ◽  
Structural Heterogeneity ◽  
Turnover Rates ◽  
Net Production ◽  
Wooded Area ◽  
Leaf Turnover ◽  
Scrub Forest

This paper reports on the seasonal changes of standing crop and production in habitats used by a high-density population of giant tortoises on Aldabra atoll. The study had two main aims: first to investigate the primary production of a raised coral atoll (to our knowledge the first such study) and secondly to provide base data for a study of the interactions of a large reptilian herbivore (the giant tortoise) with its food supply and environment. Environmental heterogeneity made it necessary to measure separately the standing crop and the above-ground net production of different components of the vegetation; these components were usually single species or small groups of species of plants. Measurements of these components were then combined with cover data for the same components in selected places to illustrate the seasonal and spatial variability of primary production on Aldabra. Standing crop biomasses were estimated from harvest samples. Methods for production estimates varied with the component studied, but included harvest difference methods, repeated clipping of the same plots and direct measurement of leaf turnover rates on marked shoots. These methods are compared where appropriate. Net annual above-ground production varied between plant types from 3165 kJ per square metre of plant for ‘tortoise turf’ to 47700 kJ m -2 for Cyperus ligularis , a robust perennial sedge. Total above-ground annual net production of different habitat types (bare ground and rocks between plants being taken into account) varied from 9100 kJ m -2 in a thinly wooded area with high tortoise turf cover (‘open mixed scrub’) to 28200 kJ m -2 in an area of thick scrub forest (‘groves’). The seasonality of production and standing crop also varied considerably between habitats, owing to the role of different components of the ground layer and shrub cover. These results are discussed in terms of the roles of environmental and structural heterogeneity in setting primary production and of the tortoises themselves in their interactions with the vegetation via trampling and grazing. The effect of this heterogeneity on sampling strategies and results is also assessed.

Estimating net primary production of forests in the Canadian Prairie Provinces using an inventory-based carbon budget model

2002 ◽  
Vol 32 (1) ◽  
pp. 161-169 ◽  
Author(s):  
Zhong Li ◽  
Michael J Apps ◽  
E Banfield ◽  
Werner A Kurz
Keyword(s):  
Primary Production ◽  
Carbon Budget ◽  
Fine Root ◽  
Net Primary Production ◽  
Root Turnover ◽  
Stand Age ◽  
Parameter Estimates ◽  
Budget Model ◽  
Carbon Budget Model ◽  
Prairie Provinces

The Carbon Budget Model of the Canadian Forest Sector (CBM-CFS2) is a forest inventory-based ecosystem simulation model. It has been used previously for both retrospective and projective analyses of the carbon pools and fluxes of the Canadian forest ecosystems at the national, regional, and stand level. The objective of this study was to determine and evaluate forest net primary production (NPP) in the three Prairie Provinces in west-central Canada, as estimated by the model. The model simulated an averaged aboveground NPP (NPPA) of 172 g C·m–2·year–1 for the regional forests, varying from 72 to 293 g C·m–2·year–1, depending on ecoclimatic province, forest type, age, and site productivity. Comparisons of NPPA estimates for the boreal forest (165–179 g C·m–2·year–1) with results from direct measurements, modeling, and empirical calculations show that the CBM-CFS2 produced reasonable estimates of NPPA. The model incorporates different types of disturbances such as wildfire, harvesting, and insects and is able to evaluate NPP changes with stand age. However, belowground NPP may be overestimated, especially for young and unproductive stands. This can be explained by the current parameter estimates for the fine-root component of belowground biomass and for fine-root turnover rates.

scholarly journals Biomass and production of an aspen – mixed hardwood – spodosol ecosystem in northern Wisconsin

1981 ◽  
Vol 11 (1) ◽  
pp. 132-138 ◽  
Author(s):  
John Pastor ◽  
J. G. Bockheim
Keyword(s):  
Primary Production ◽  
Root Biomass ◽  
Net Primary Production ◽  
Average Rate ◽  
Leaf Tissue ◽  
Allometric Equations ◽  
Annual Production ◽  
Total Biomass ◽  
Total Production ◽  
Unit Leaf

Total biomass of an aspen – mixed hardwood – spodosol ecosystem in northern Wisconsin, U.S.A., was 197 t/ha and net primary production was 11.5 t/ha per year. Populustremuloides Michx. accounted for 60% of the total biomass and 56% of the annual production and Acersaccharum Marsh, accounted for 25% of the biomass and 28% of the annual production. For all species combined, bole wood was 63% of the total biomass and bole bark was 12%. Bole wood was 33% and bole bark was 7% of the total production. Although crowns accounted for only 15% of the total biomass, they were responsible for 49% of net annual production. Using allometric equations from the literature, root biomass and production were calculated as being approximately 10% of the total biomass and of the annual production. The average rate of total production per unit leaf tissue was 5.7 g production/g leaf tissue for P. tremuloides and 3.7 g/g for A. saccharum.

Belowground biomass dynamics in the Carbon Budget Model of the Canadian Forest Sector: recent improvements and implications for the estimation of NPP and NEP

2003 ◽  
Vol 33 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Zhong Li ◽  
Werner A Kurz ◽  
Michael J Apps ◽  
Sarah J Beukema
Keyword(s):  
Primary Production ◽  
Root Biomass ◽  
Carbon Budget ◽  
Fine Root ◽  
Net Primary Production ◽  
Fine Root Biomass ◽  
Forest Sector ◽  
Regression Equations ◽  
Budget Model ◽  
Carbon Budget Model

In the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS2), root biomass and dynamics are estimated using regression equations based on the literature. A recent analysis showed that some of these equations might overestimate belowground net primary production (NPPB). The objectives of this study were to update the compilation of root biomass and turnover data, to recalculate the regression equations and to evaluate the impact of the new equations on CBM-CFS2 estimates of net primary production (NPP) and net ecosystem production (NEP). We updated all equations based on 635 pairs of aboveground and belowground data compiled from published studies in the cold temperate and boreal forests. The new parameter for the equation to predict total root biomass for softwood species changed only slightly, but the changes for hardwood species were statistically significant. A new equation form, which improved the accuracy and biological interpretation, was used to predict fine root biomass as a proportion of total root biomass. The annual rate of fine root turnover was currently estimated to be 0.641 of fine root biomass. A comparison of NPP estimates from CBM-CFS2 with results from field measurements, empirical calculations and modeling indicated that the new root equations predicted reasonable NPPB values. The changes to the root equations had little effect on NEP estimates.

Sign in / Sign up

Export Citation Format

Share Document