PBG03 Disk pasture meter measurements to estimate plant standing biomass in the Patch-Burn Grazing experiment at Konza Prairie

Abstract:

"PBG" datasets are associated with a long-term, large-scale study that is addressing the effects of fire-grazing interactions in the context of a Patch-Burn Grazing management system designed to promote grassland heterogeneity. Effects of patch-burn grazing management on plant and animal diversity and the nature and variety of wildlife habitat are being assessed in two replicate management units, each consisting of three pastures (watersheds) designated C03A/C03B/C03C and C3SA/C3SB/C3SC. In each patch-burn grazing unit, one watershed is burned and two that are left unburned in a given year. The burning treatments are rotated annually so that each pasture is burned every third year. Each patch-burn grazing unit is paired with an annually-burned pasture for comparison with traditional grazing systems (C01A and C1SB). All grazing units are stocked with cow/calf pairs from approximately 1 May until 1 Oct at a stocking density equal to 3.2 ha per cow/calf. To examine the impact of patch burning and grazing in all 8 units, we monitor changes in plant species composition, residual biomass, grassland bird populations, insect populations, small mammal populations, soil nutrients, and stream water quality1 (1C3SA/C3SB/C3SC unit only). The KSU Department of Animal Science monitors cattle performance, including weight gain and body condition to assess the economic feasibility of using patch-burn management on a widespread basis. This dataset includes both the annual calibration data for the disk pasture meter measurements (PBG031) and the actual disk pasture meter measurements in the PBG experiment (PBG032). Measurements were taken at a total of 64 transects (8 watersheds x 4 sites per watershed x 2 pasture meter transects per site). Each cattle-grazed watershed (designated as of May 2011 C3A, C3B, C3C, and C1A) and the four Shane cattle-grazed watersheds (C1B, C3SA, C3SB, and C3SC) includes 4 plant composition sampling transects (A-D). Pasture meter measurements were taken along two transects adjacent and parallel to the plant composition transects in each of these watersheds. Standing biomass samples for pasture meter calibration were also collected near the plant composition transects in the same 8 watersheds.

Core Areas:

Data set ID:

117

Short name:

PBG03

Purpose:

To estimate aboveground biomass using vegetation structure height profiles in eight grazed watersheds of varying burn history.

Methods:

Location of Sampling Stations: Measurements were taken at a total of 64 transects (8 watersheds x 4 sites per watershed x 2 pasture meter transects per site). Each cattle-grazed watershed (designated as of May 2011 C2A, C3B, C3C, and C1A) includes 4 plant composition sampling transects (A-D). Pasture meter measurements were taken along two transects adjacent and parallel to the plant composition transects in each of these watersheds. Standing biomass samples for pasture meter calibration were also collected near the plant composition transects in the same 8 watersheds.

For example: In watershed C3A, there are 4 plant composition transects (labeled A-D). Two pasture meter transects (50 m) will be placed at each of these sites.

Frequency of Sampling: Sampling occurred annually in late summer or early fall. The first measurements were taken in August 2010.

Variable Measured: Standing biomass, vegetation structure height

Methods: Measurements of vegetation structure height were taken along two 50m transects approximately 25m on either side of and parallel to each of the 32 designated plant composition transects. A disc pasture meter was used to take 50 measurements per transect (1 measurement per meter). The disc apparatus was raised to the top of the measuring stick, released, and allowed to settle on the standing vegetation. The height of the vegetation in centimeters was then read from the measuring stick.

To calibrate the pasture meter, standing biomass was collected at 25-30 different locations across multiple watersheds. Care was taken to ensure the samples included a wide range of standing biomass. First, a vegetation structure height measurement was taken and recorded. Then, a circular clipping frame was placed in the same location and all biomass in the ring was clipped, bagged, dried, and weighed. These data were then used to create a regression relationship between standing biomass and vegetation structure height. The resulting equation can then be used to estimate standing biomass along each of the vegetation structure height transects.

For additional metadata information see: http://lter.konza.ksu.edu/sites/default/files/DC.pdf

For additional methods information see: http://lter.konza.ksu.edu/sites/default/files/MM.pdf