Groundcovering Measuring Tool
Published by the Victorian Government Department of Primary Industries, 2005
How to use these tools
The first section of this monitoring gives an introduction to the term groundcover, followed by two tools to help you monitor groundcover. The tools contain steps to help guide you through the processes, plus some simple calculations and tips on how to monitor your current groundcover situation.
TOOL A: Visual Assessment
TOOL B: Field Assessment - wire and step point method
Monitoring is an essential component of developing an Environmental Management System (EMS). The 'groundcover monitoring tool' outlined below has been developed to help farmers and advisers in southern Australia to measure and understand the importance of groundcover on farms. Managing groundcover can ensure that soils do not become susceptible to degradation caused by erosion from wind and water.
The tools allow farmers to assess the current groundcover conditions using a range of different techniques. Groundcover assessments are seasonably variable, hence this tool will highlight the need to consistent monitoring and recording.
The groundcover tool will provide some management techniques to ensure adequate groundcover throughout the year and will make reference of how this tool can be used in conjunction with the Sustainable Livestock Carrying Capacity Tool.
What is groundcover?
Groundcover is the amount of plant material (dead or alive) which covers the soil surface. It is usually expressed in percentage terms – 100% groundcover means that the soil cannot be seen and 0% groundcover is bare soil. In most landscapes there is usually some form of groundcover on the soil surface. Farming systems have groundcover in the form of annual or perennial pastures or crops. Native vegetation areas will also benefit from groundcover assessments, however management of these areas is quite different to managing introduced species. See the Remnant Vegetation Monitoring Tool for further information. Weeds can be a form of groundcover but they have obvious effects of a decline in production and raise environmental concerns.
Common scenarios in which groundcover may be reduced is through over grazing, times of drought, cropping, tilling, poor seed establishment, chemical removal and excessive trafficking.
Groundcover can be estimated visually and through simple field measurements. The following monitoring tools will provide a range of different monitoring techniques. You can decide to use just one of the tools or both, depending on how you prefer to monitor and how much time you have.
Goal: To maintain groundcover at a minimum of 70% to prevent soil erosion from wind and water. Groundcover includes both living and dead plant material and litter.
- STEP 1. Select areas to monitor.
Firstly think about what it is that you are trying to achieve by monitoring groundcover. Is it to rehabilitate a known degraded area? To assess pasture cover for potential increases in animal carrying capacity? Or generally to assess the groundcover of the entire property to assess your risk of soil erosion? Whatever the reason it is important to record the areas monitored, stating specifically where the assessments were taken and if possible, marking the areas on a farm map. This will allow you to assess groundcover over time.
- STEP 2. Decide the time of year when groundcover is at its lowest level.
Groundcover is seasonably variable, therefore it is important to take into consideration the times of the year that the monitoring has taken place and in some cases it may be advantageous to monitor twice a year, again recording the dates in which the assessments have occurred. In southern Australia groundcover is often at its lowest level prior to the autumn break and therefore this is the best time to assess the risk of soil loss through erosion.
- STEP 3. Choosing a representative area.
When monitoring it is important to make sure that the areas being assessed are representative of the entire area, therefore it is a good idea to take a few assessments in the one area to make sure that you are not unknowingly creating a biased assessment. The best way to achieve this is to walk along an imaginary transect line, diagonally across the paddock from post to post, Figure 1 or take 10 steps in one direction then randomly turn and take 10 steps in the other direction, Figure 2. points
Figure 1. Transect
|Figure 2. Zig Zag- random|
The larger the area, the more assessments you need to take. Once you have had a quick walk over the general area, you will begin to understand how variable the groundcover is. If an area seems quite uniform, then perhaps 8-10 assessments will give you a good indication of the average groundcover. In areas of high variability, take at least 15 or more assessments (depending on the size of the paddock or area).
Draw your transect roughly on a piece of paper and note approximately where the assessments were taken, remember to mark on the drawing where North or the top of the paddock to give you a reference point. Use a GPS (Global Positioning System) if you have access to this equipment. This is not an essential part of the step, but it can add to the rigour of your monitoring, remember it depends on how much time you have and how you like to monitor.
- STEP 4. Estimate the groundcover.
Make a 30 cm x 30 cm quadrat (square) out of sturdy cardboard or wire. A quadrat is used to help focus the eye on a defined area for assessment.
Along the pre-determined transect line, see Figures 1 and 2, throw the quadrats out at random and visually assess the groundcover in the quadrant, comparing it with the photo standards in Appendix A. Record the assessments in the pro-forma table provided below.
- STEP 5. Photographic records.
Photographic records can be used in conjunction with the visual assessment as a permanent reminder of what the pasture cover was like when being assessed. It is important to take the photos in the same spot each time and also to ensure that the photos are taken approximately at the same times of the day, say between the lightest hours of 9am-3pm. Always have the sun behind the camera when shooting and make sure that the date is recorded, if not through the camera function then on a piece of paper on the ground in the photo shot.
To ensure that the photos have been taken in the same spot, use the rough drawing you may have developed in step 3, and mark down at which points the photos were taken for future reference. Try to take a few photos of the different ranges of cover. Either file the photos on the computer, if digital, remembering to name and date the file, or once developed put in an album or scrap book for future reference, again dating the pictures.
Pro-forma sheet for recording groundcover assessments
|Assessment location||Date of assessment||Transect type eg, line transect or random||Sample no. eg 1, 2, 3 etc.||Percentage groundcover|
|Eg: Paddock 10B||12-12-04||Line||1||70%|
|Eg: Paddock 10B||12-12-04||Line||2||90%|
Pro-forma sheet for calculating average groundcover assessments
Averaging the measurements in each area monitored will give you an overall % groundcover figure for that area. These can then be compared to other areas of the farm and priority can be made to the areas of low groundcover % in regards to on ground works.
Average percentage % of all assessments:
Add up all the percentages taken in the same area and divide that by the number of assessments taken. Then multiply by 100 to give and average percentage of groundcover for that area.
Eg. Add up the 5 samples taken in paddock 10B: 70%+ 90%+ 40% +70% + 40% = 310%
Then divide the total of the samples by the number of samples taken: 310/5 = 62%
| Assessment location|
| List samples taken (%)|
| Total of samples taken|
| No. of sample taken|
| Average percentage of groundcover|
|Eg: Paddock 10B||70, 90, 40, 70, 40||310||5|| (C / D) = E|
310/5 = 62%
Different levels of minimum groundcover (and herbage mass can also be important) are needed for different soil types and regions. Minimum levels for pastures in south-eastern Australia are suggested to be:
- 70% for pastures on flat and slightly sloping (<3%) land and on non-erosion prone soils (moderate-good soils generally). Herbage mass should be a minimum of 800-1200kg dry matter (DM)/ha.
- 80-90% groundcover for lighter, more erosion prone soils and Minimum herbage mass should also be 1000-1500kg DM/ha.
where land is undulating.
- 90-100% groundcover for steep hill country on light and erosion prone soils (eg slopes of greater than 10%, granite or light sedimentary soils with low fertility and often high acidity). Herbage mass should be a minimum of 1500kg DM/ha.
In areas such as the Mallee and Western Australia, 50% is often used as the minimum groundcover percentage. If you have less than the minimum groundcover percentages at the critical time, then your stocking rate is too high for sustainability.
Groundcover % figures are given in Appendix A (at the back of the document), ranging from 20100% to help you assess your groundcover levels. (These were supplied by Greg Lodge NSW DPI for the 20, 40 and 70% levels and for the remainder, Primary Industries South Australia, 1996, Pasture Pics: easy estimation of pasture dry matter levels, Appila / Bundaleer Pasture Group, Appila, SA.)
Tool B: Field assessment - the wire or step point method
- Step 1. Select areas to monitor.
- Step 2. Decide the time of year when groundcover is at its lowest level.
The first 2 steps of this method are the same as in the Visual Assessment method on page 2.
- Step 3. Choosing a representative area.
When monitoring it is important to make sure that the areas being assessed are representative of the entire area. It is a good idea to take a few assessments in the one area to make sure that you are not unknowingly creating a biased assessment. For the wire and step point method it is recommended that you divide the area to be assessed into 4 line transects (use fences posts or trees to help guide your path along the transect) and sample 25 times at random along the transect.
Figure 3. Transect
- Step 4. Estimate the groundcover.
A painted white nail in the end of your leather boot or a straight piece of fencing wire that reaches approximately to your shoulder height, with one end of the wire bent to form a handle
Taking the readings:
- Hold the wire at arms length and shoulder height, with the tip straight down but not touching the ground
- Look straight ahead along your transect line, and take two or more steps along the line (depending on how long the line is to how many steps you can take).
- After your second or so step, lower the point of the wire onto the ground or if using the step point method, just take the steps and then look down.
- Look down and record the presence (yes) or absence (no) of surface cover directly under the point of the wire or at the tip of the nail in your boot on the pro-forma sheet below.
- After recording the result, repeat steps 1-4 until you have recorded 25 sample points along the transect.
Example: PRO-FORMA SHEET FOR RECORDING GROUNDCOVER ASSESSMENTS WITH WIRE AND STEP POINT METHOD.
|Location:||Old school paddock|
TOTAL YES (A) divided by TOTAL SAMPLES TAKEN – A / (A+B) = D
TOTAL YES divided by TOTAL SAMPLES TAKEN – 53 / 100 = 0.53
|Percentage Cover = 53%|
PRO-FORMA SHEET FOR RECORDING GROUNDCOVER ASSESSMENTS WITH WIRE AND STEP POINT METHOD.
TOTAL YES (A) divided by TOTAL SAMPLES TAKEN – A / (A+B) = D
TOTAL YES divided by TOTAL SAMPLES TAKEN– ____/____= ____
|Percentage Cover = 53%|
MANAGEMENT TECHNIQUES TO ENSURE ADEQUATE GROUNDCOVER THROUGHOUT THE YEAR
Avoid overgrazing: Stocking rates should be calculated on the amount of available dry matter per head of stock, refer to the Sustainable Livestock Carrying Capacity tool for instructions on how to monitor carrying capacity.
Cropping: Crops need to be managed so that groundcover is provided thorough out the year, as intense rain and wind events can lead to erosion and degraded soil structure if crop cover is burnt of buried. The management option of stubble retention and minimal tillage are the best ways to ensure maximum groundcover retention, more efficient water use and greatest control of erosion (DPI QLD).
Hunt, N and Gilkes, B (1992) Farm monitoring handbook. University of Western Australia, Nedlands Western Australia.
Primary Industries South Australia, 2003, Andrea Francis Rural Solutions SA, Richard Payne DWLBC, Fact sheet no: 8/01. Field methods for measuring soil surface cover.
Primary Industries South Australia, 1996, Pasture Pics: easy estimation of pasture dry matter levels, Appila / Bundaleer Pasture Group, Appila, SA.
Sustainable Grazing Systems Key Program information can be found on the www.mla.com.au website. Search Tips & Tools and Fact sheets on the home page.
Land Manager's Monitoring Guide, CD Version, 2005, Community and Landscape Sciences, Natural Resource Sciences, Queensland Department of Natural Resources and Mines
Figure 4: 20% cover
Figure 5: 40% cover
Figure 6: 50% cover
Figure 7: 80% cover
Figure 8: 90% cover
Figure 9: 100% cover
Greg Lodge, NSW DPI – 20% and 40% cover photographs.
Primary Industries South Australia, 1996, Pasture Pics: easy estimation of pasture dry matter levels, Appila / Bundaleer Pasture Group, Appila, SA - 50, 80 and 100% photographs.