VCR LTER DatasetVCR03088 - Root data from pits on Hog Island transect 2Basic Information, Text, Variables, Download Data, R, SPSS or SAS Program EML Metadata |
Dataset ID:VCR03088
Dataset Title (Identity):Root data from pits on Hog Island transect 2
LTER Core Areas: Organic Matter, Site Physical Characteristics
Collection Started (MM/DD/YY): 06/01/89 Collection Ended: 08/31/89
General Location Where Data Was Collected: Transect 2 on the north end of Hog Island
Form of the Data: Column
Keywords: Dune, Myrica cerifera, Root diameter, Spartina patens, biomass, root,
Understanding belowground processes and how they link with overall system dynamics has lagged far behind out extension of knowledge of aboveground processes. In root studies that have been completed, large roots (> 5mm diameter) have frequently been inadequately sampled. As a pilot study preceeding more refined quantification of fine root dynamics, the proposed project will determine the distribution of root mass (with particular interest in large roots) by soil depth along already established transects on Hog Island. These transects extend along topographic and successional gradients in accreting and eroding areas of the island. Pit excavations will be used. The results will provide useful information for adjusting future sampling regimes for root dynamics and will also provide the best estimates of large root mass.
Sample stations (4-6) will be located along the Hog Island transects 1 and 4. At least 10 to 15 0.25 m2 pits will be excavated to 40 cm depth at each station during the summer of 1989. The roots will be separated form the soil by washing and seiving, characterized by size class, dried at 70 degrees C and weighed. Differences in root mass by depth, size classes, and transect position will then be statistically evaluated.
04/15/90:
Understanding belowground processes and how they link with overall system dynamics has lagged far behind our extension of knowledge of aboveground processes. In consideration of the great importance of belowground dynamics, precision studies of root production and turnover in relation to the microenvironmental regulatory complex are needed. The Virginia Coast Reserve LTER site provides an opportunity to approach eseresearch goals in the context of a nutrient poor, physically dynamic landscape. A broad spatial and temporal perspective is required in this system as the landscape is shifting and changingin time and space. There is a need to understand the links between belowground processes and the exceptionally dynamic microenvironment of the barrier islands.
The overall objective of this study is to quantify root production and turnover along a topographic gradient on Hog Island and relate these processes to the microenvironmental complex as precisely as possible. The specific objective of the 1989 field work was to conduct a pilot study to determine the distribution of root mass (with particular interest in large roots) by soil depth along already established transects on Hog Island. These transects extend along topographic gradients in accreting and eroding areas of the island. Pit excavations were used. The results provided an initial picture of root distribution patterns and will provide a framework for planning process related studies in subsequent field seasons.
METHODS
The study made use of the system of transects established on Hog Island. Sample stations were located along transect 2 on the northern, accreting end of the island. The communities on the northern end of the island grade inland from open beach to Ammophila breviligulata dominance to dense Spartina patens to Myrica cerifera thickets. Five stations were positioned along the transect to span the gradation in elevation and to represent major community types. From east to west, the communities sampled were an Ammophila dominated dune, a Spartina patens interdunal marsh, a Myrica thicket, an interior Spartina patens marsh, and an older Myrica stand.
Ten sample points per station were randomly located within a 100 m 2 area. At each point, a 0.25 m 2 pit was excavated in 10 cm depth intervals to 40 cm during the summer of 1989. The marsh sites were excavated to 20 cm because of high water. The roots were separated from the soil by washing and seiving, categorized by major diameter classes, dried at 70 C and weighed. The roots are currently being analyzed colorimetrically for total N and P on a Scientific Instruments Autoanalyzer.
Variation in root mass by depth, size class, topographic position, and community type will be statistically evaluated by ANOVA and appropriate a posterori tests. The analysis has not yet been completed.
RESULTS
In this study, the Spartina communities experienced periodic flooding and the root zone was commonly saturated. The Myrica stands and the Ammophila community occupied higher micro topographic positions and were generally found on sandier soils. Presumably the older communities are located toward the island interior. On the sites excavated to 40 cm, most root biomass was in the top 20 cm of soil (Table 1). Distribution of root mass among size classes varied among sites. The mass of large roots was greater than fine roots in the top 20 cm on the shrub sites and dune, but the opposite was observed on the Spartina sites. On the Spartina sites, most of the biomass was in the < 2 mm size class. The 2 - 5 mm size class dominated the dune site, and the > 5 mm size class dominated the Myrica sites. Young (pers. comm.) has suggested that nodulation in Myrica is more abundant toward the ocean and near the surface on larger roots. Our study indicated that the large surficial roots are prominant in the Myrica communities. Fine root biomass (< 2 mm diameter) in the top 10 cm of soil was greater on the Spartina sites than the Myrica sites, but there was very little difference among sites at the lower depths (Table 1). The fine root biomass in the top 10 cm increased toward the island interior among the grass sites and among the shrub sites. The same pattern held for larger roots among the shrub sites. Several clear and interesting patterns in biomass were apparent; variation in process rates should also be expected.
The N and P analyses and statistical analysis of the data should be complete by summer 1990. The results of this initial study will provide a framework for guiding process related studies we hope to initiate in 1990.
| Variable | Units | Description |
|---|---|---|
| SITE | Site designation | |
| REP | ||
| DEPTH | Depth in soil profile | |
| SIZE | Root diameter | |
| MASS | g/0.09m2 | Oven dry weight |
| Code | Value |
|---|---|
| 1 | Frontal dune ~ 6 year |
| 2 | Young Spartina patens marsh ~ 24 year |
| 3 | Young Myrica cerifera ~36 year |
| 4 | Old Spartina patens marsh ~ 36 year |
| 5 | Old Myrica cerifera ~ 120 year |
| Code | Value |
|---|---|
| 10 | 0-10 cm belowground |
| 20 | 10-20 cm belowground |
| 30 | 20-30 cm belowground |
| 40 | 30-40 cm belowground |
| Code | Value |
|---|---|
| 1 | <2 mm diameter |
| 2 | 2-5 mm diameter |
| 3 | >5 mm diameter |
|
Frank P. Day |
Core Areas | Sampling Methods |
|---|---|
|
Primary Productivity Organic Matter Nutrient Movements |
Harvest Core |
| Dataset ID | Contact | Dataset Identity |
|---|---|---|
| VCR03089 | fday | Nutrients in roots on Hog Island, VA 1989 |
| VCR03090 | fday | Root biomass on Northern Hog Island |
Understanding belowground processes and how they link with overall system dynamics has lagged far behind out extension of knowledge of aboveground processes. In root studies that have been completed, large roots (> 5mm diameter) have frequently been inadequately sampled. As a pilot study preceeding more refined quantification of fine root dynamics, the proposed project will determine the distribution of root mass (with particular interest in large roots) by soil depth along already established transects on Hog Island. These transects extend along topographic and successional gradients in accreting and eroding areas of the island. Pit excavations will be used. The results will provide useful information for adjusting future sampling regimes for root dynamics and will also provide the best estimates of large root mass.
Sample stations (4-6) will be located along the Hog Island transects 1 and 4. At least 10 to 15 0.25 m2 pits will be excavated to 40 cm depth at each station during the summer of 1989. The roots will be separated form the soil by washing and seiving, characterized by size class, dried at 70 degrees C and weighed. Differences in root mass by depth, size classes, and transect position will then be statistically evaluated.
04/15/90:
Understanding belowground processes and how they link with overall system dynamics has lagged far behind our extension of knowledge of aboveground processes. In consideration of the great importance of belowground dynamics, precision studies of root production and turnover in relation to the microenvironmental regulatory complex are needed. The Virginia Coast Reserve LTER site provides an opportunity to approach eseresearch goals in the context of a nutrient poor, physically dynamic landscape. A broad spatial and temporal perspective is required in this system as the landscape is shifting and changingin time and space. There is a need to understand the links between belowground processes and the exceptionally dynamic microenvironment of the barrier islands.
The overall objective of this study is to quantify root production and turnover along a topographic gradient on Hog Island and relate these processes to the microenvironmental complex as precisely as possible. The specific objective of the 1989 field work was to conduct a pilot study to determine the distribution of root mass (with particular interest in large roots) by soil depth along already established transects on Hog Island. These transects extend along topographic gradients in accreting and eroding areas of the island. Pit excavations were used. The results provided an initial picture of root distribution patterns and will provide a framework for planning process related studies in subsequent field seasons.
METHODS
The study made use of the system of transects established on Hog Island. Sample stations were located along transect 2 on the northern, accreting end of the island. The communities on the northern end of the island grade inland from open beach to Ammophila breviligulata dominance to dense Spartina patens to Myrica cerifera thickets. Five stations were positioned along the transect to span the gradation in elevation and to represent major community types. From east to west, the communities sampled were an Ammophila dominated dune, a Spartina patens interdunal marsh, a Myrica thicket, an interior Spartina patens marsh, and an older Myrica stand.
Ten sample points per station were randomly located within a 100 m 2 area. At each point, a 0.25 m 2 pit was excavated in 10 cm depth intervals to 40 cm during the summer of 1989. The marsh sites were excavated to 20 cm because of high water. The roots were separated from the soil by washing and seiving, categorized by major diameter classes, dried at 70 C and weighed. The roots are currently being analyzed colorimetrically for total N and P on a Scientific Instruments Autoanalyzer.
Variation in root mass by depth, size class, topographic position, and community type will be statistically evaluated by ANOVA and appropriate a posterori tests. The analysis has not yet been completed.
RESULTS
In this study, the Spartina communities experienced periodic flooding and the root zone was commonly saturated. The Myrica stands and the Ammophila community occupied higher micro topographic positions and were generally found on sandier soils. Presumably the older communities are located toward the island interior. On the sites excavated to 40 cm, most root biomass was in the top 20 cm of soil (Table 1). Distribution of root mass among size classes varied among sites. The mass of large roots was greater than fine roots in the top 20 cm on the shrub sites and dune, but the opposite was observed on the Spartina sites. On the Spartina sites, most of the biomass was in the < 2 mm size class. The 2 - 5 mm size class dominated the dune site, and the > 5 mm size class dominated the Myrica sites. Young (pers. comm.) has suggested that nodulation in Myrica is more abundant toward the ocean and near the surface on larger roots. Our study indicated that the large surficial roots are prominant in the Myrica communities. Fine root biomass (< 2 mm diameter) in the top 10 cm of soil was greater on the Spartina sites than the Myrica sites, but there was very little difference among sites at the lower depths (Table 1). The fine root biomass in the top 10 cm increased toward the island interior among the grass sites and among the shrub sites. The same pattern held for larger roots among the shrub sites. Several clear and interesting patterns in biomass were apparent; variation in process rates should also be expected.
The N and P analyses and statistical analysis of the data should be complete by summer 1990. The results of this initial study will provide a framework for guiding process related studies we hope to initiate in 1990.
The proposed project would involve excavation of small pits. These would represent a very small area, and the pits can be filled in. Rigid scheduling is not required.
The proposed study is a pilot to more extensive work being proposed to NSF. One published paper and a couple of oral presentations would likely result.
Belowground sampling by Bill Odum in marshes.
Montague, K.A. and F.P. Day. 1980. Belowground biomass of four plant communities o fthe Great Dismal Swamp, Virginia. Amer. Midl. Nat. 103: 83-87.
Symbula, M. and F.P. Day. In press. Evaluation of two methods for estimating belowground production in a freshwater swamp forest. Amer. Midl. Nat.
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