Field-based grazing measurements | MBFP | More pastured beef (2024)

Grass mass can be assessed by cutting, drying and weighing representative pasture samples, or by using tools of varying levels of sophistication.

Grassland assessment tools save a lot of time in collection and are considered the only practical method to use when making daily assessments. Three broad groups of instruments are used to measure grass mass:

• Grass rulers or 'sticks' that measure grass height are simple, cheap and easy to use. Using look-up tables, heights can easily be converted into an estimate of kg of green DM/ha.
• Figure 1: The MLA Grassland Ruler - order your copyherfree

Also take a look at this practical oneto understand how to get the most out of the Grassland Ruler.

• Grass density should also be estimated and used as a correction factor when growing or mature grassland is less than 100% of the ground cover. See below the land cover and grazing composition assessment method, which can be used to estimate the percentage density of grassland.
• The measurements also provide an indication of the mass of dry food, but usually underestimate the value. PROGRESS^®comments describe a method to customize.
• With experience, you can use the height estimation method to obtain reasonably accurate estimates of mass, especially if you periodically compare it with estimates made by cutting and weighing.

• Rising plate meters measure total grass mass, green and dry forage and are based on a plate that rises with a probe depending on the amount of compressed grazing material between the plate and the ground.

  • Advanced models are available that collect and store field measurements to average values ​​in a meadow or a number of meadows
  • They are available from a number of commercial outlets and the price usually depends on the degree of automation of the collection.
  • Generally slightly cheaper than electronic probes and may be preferred when frequent automated assessment of pastures with significant amounts of non-green grass is required.

• Electronic grazing probes only measure the dry matter of the green material.

  • They are fast, easy to use and usually fully automatic, including the ability to download measurements directly to office computers.

    See Also

    Pasture.io - Riser meterOdometer | Wheels | MeasurementMowing practices for healthy lawnsThe nutritional value of grass guide

  • Some also allow collecting user-defined and read assessments, such as land cover or phenology.
  • The accuracy decreases if there is free moisture in the pasture (for example after rain or heavy dew).

These are generally the most expensive of the three groups.

Satellite images are currently being experimentally evaluated to measure the growth and abundance of grasslands in South Australia. See the Pastures from Space websitewww.pasturesfromspace.csiro.aufor information only

There are numerous commercially available meters and probes available on the Internet (search for "pasture + meter"). Most national utility companies will also assist in locating commercially available models.

Measuring grass height using the ruler/stick method

Use a plug of 1 cm thick, approximately 30 cm long. Draw a mark 0.5 cm from the bottom and then every 1 cm along the stick. Readings between 0.5 cm and 1.5 cm are recorded as 1 cm, measurements between 1.5 cm and 2.5 cm as 2 cm, etc. Measure the height from at least 50 randomly selected locations while crossing the fold. The best way is to throw the stick while walking across the paddock.

To measure the scrape, place the stick vertically on the ground surface at the point where the bottom of the stick landed. Slide your thumb down the stick until you touch a green leaf and note the cm. Record this on the registration sheet.

Grass height registration sheet

Open the PDF to print the grass height registration sheet

Estimated correlation between grazing height and kg DM/ha

Source: PROGRAZE Victoria Manual, 2009

Example of a completed grass height record

Under cover

Land cover includes existing grassland, weeds and other crops and waste. To assess ground cover, stand in a representative part of the pasture with your feet two feet apart. Imagine you have half a square meter in front of you and look vertically into the pasture, estimate the percentage of the area covered by plant material and debris. Walk around the paddock and repeat the assessment at approximately 30 random locations. Record and average the results to accurately determine the percent ground cover. To seeTool 2.2for detailed information.

Composition of grassland

There are a number of methods to measure grass composition. Which one you choose will likely depend on the amount of area you want to sample and the time you have available to complete the assessments.

Described below:

• PROGRAZE stick method
• Transect method
• Engine method
• Quadratic method
• Blundstone-methode.

These have been takenTowards sustainable grazing – Weed removers, pasture improversworkshop notes.

PROGRAZE stick method

You can use the same stick you used to estimate the height of the grass. Drive a nail into the top of the dowel so it can measure both its height and composition.

1. Select a transect over the paddock
2. Throw the stick
3. Use the accompanying recording sheet to note which plant species touches the head of the nail
4. Walk some steps
5. Repeat the above until the paddock has been crossed
6. Calculate the percentage of hits for each species/grouping.

Transect method

Similar to the PROGRAZE stick method, but without the stick.

1. Placing a transect and marking it permanently (for example by painting fence posts on each side of the paddock)
2. Walk the transect, stopping every x steps (x is determined by the length of the transect, but should be sufficient to sample up to 50 points)
3. At each point, note which species is touching the toe of your right boot
4. Continue the process until enough observations have been made
5. Calculate the percentage of hits for each species/grouping.

Engine method

For an experienced person with a trained eye, this is a quick assessment method that is especially good for large folds.

1. Drive the fold in an even manner – from corner to corner is a good suggestion
2. Every 100 meters (on the odometer) or count 20-30 seconds, stop the bike and note the species that is on the toe of your boot
3. Continue until 50 points have been recorded
4. Calculate your composition.

Rating sheets for the PROGRAZE Stike Transect and Motorcycle methods

Open the PDF to print below: Assessment Sheet for PROGRAZE Stike Transect and Motorbike Methods.pdf

A square is a means of defining a small sample area that can be evaluated.

1. Place quadrat on the ground
2. Stand vertically above the square (view from the helicopter) and estimate the proportion of the square's area occupied by each species species
3. Record the proportions on the worksheet
4. Repeat the process until enough locations have been sampled
5. Calculate the average coverage for each species.

1. Stand in the fold with your feet about two feet apart
2. Visualize a 0.5 x 0.5 m square in front of your toes
3. Estimate the proportion of this square occupied by each plant type
4. Take at least five random guesses from five different parts of the pasture to get a reliable indication of the composition of your pasture
5. Write your results on the worksheet.

Open the PDF to print below: Quadrat and Blundstone Methods Assessment Sheet.pdf

Guidelines for composition measurements

• Legume component of pastures to supplement introduced grasses – minimum 20%, maximum 30%, unless paddocks are specifically to be used for high animal production (growth rates) when a higher maximum legume content may be desirable (up to 40%). Take precautions to prevent swelling in livestock when legume levels approach maximum limits.
• Legume content in native pastures – maximum 20%.
• Productive and perennial grasses – minimum 60%, maximum 80%.
• Annual grass and broadleaf weeds – max. 10%.
• Bare soil – maximum 10%.
• Noxious weeds - maximum 0%.

The most appropriate number and relative proportion of desirable perennial grass species within the total perennial grass component of a pasture will vary depending on the genetic capacity for growth and quality of each species and the objectives set for that grazing area. The limits in the following table are indicative only:

• High input grass pastures – maximum limit of two desired grass species (grazing management issues increase with the number of species), with a combined minimum composition of 90% of the total grass component of the grazing mixture.
• General purpose grazing areas (native, introduced or a mixture) – a minimum of two desirable grass species, with the dominant species accounting for a maximum of 60% of the total desired grass component.
• Special purpose grazing – boundaries will be determined by purpose (e.g. one species such as tetraploid ryegrass can be used in a high-quality short-term pasture).

Assessment of phenology is done for target species and involves examining individual shoots of perennial grass clumps to count the number of new leaves on each shoot. The number of leaves is a good indicator of the onset of senescence (death) of the oldest leaf on each tiller. In general, the ideal number is between three and four cutters; however, the number of leaves varies from species to species.Figure 1indicates the relationship between water-soluble carbohydrate content and leaf number for perennial ryegrass.

Figure 1: Regrowth of one perennial grass cutter

Module 3 Grazing utilizationcontains information on the number of actively growing leaves for different species, plant-based grazing methods and guidelines for monthly growth rates in the regions of South Australia.

It is important that you can estimate the growth rate of the meadows for your own plot, so that you can better coordinate your pasture management.

To estimate the pasture growth rate of a paddock under rotational grazing;

1. Estimate the herb mass kg DM/ha when the stock leaves the paddock (A)
2. Estimate the herb mass in kg DM/ha at some point in the future (e.g. 30 days after the cattle leave the paddock)(B)
3. Record number of days between measurements (e.g. 30 days)(days)

Calculation is: (B – A) / days = _____kg DM/ha/day

Example: Grass height 1,200 kg DM/ha when leaving the meadow. 30 days later, grazing was assessed at 1,900 kg DM/ha, so (1,900 – 1,200)/30 = 23 kg DM/ha/day.

If the cattle are in a pasture and you need to estimate growth rate you can use the following method as described in the Grazing Management Checklist for Northern Rivers in NSW.

1. Calculate the average stocking rate (DSE/ha) for the period between the two plant mass estimates (SR)
2. Calculate the number of days in the relevant period (T)
3. Estimate the herb mass (kgDM/ha) at the beginning of the period (HM1)
4. Estimate the herb mass (kgDM/ha) at the end of the period(HM2)

The calculation is: (SR xT) + (HM2 – HM1) / T = _____kgDM/ha/day

Example: 24 steers of 300 kg grow at 1 kg LW/day. Heifers with this weight and growth rate have a DSE rating of 10. They graze an area of ​​20 hectares. Therefore, the average cover species for this area is (24 x 10)/20 = 12DSE/ha.

60 days have passed between herbal assessments. The first herb estimate was 1,300 kg DM/ha. The second herb estimate was 1,500 kg DM/ha

And: (12 × 60) + (1500 – 1300) / 60 = 15 kg DS/ha/dag

Drainage rate is estimated by taking a full 9-gallon plastic garden watering can and, with the sprinkler top in place, pouring the water evenly over a representative square foot of soil area (soil and plant material). End the ramp after 60 seconds. Any drainage or excavation that occurs at the end of this period is indicative of poor infiltration rates, but will depend on current soil moisture levels.

A full laboratory analysis is usually required to assess pasture quality (energy content). Field observations provide useful guidance on the energy content in MJ ME/kg DM. Actively growing green material is normally between 11.0 and 12.0 MJ ME/kg DM. Actively growing legumes generally have a slightly higher energy content (+ 0.5MJ ME/kg DM) than perennial grass. Therefore, it can be assumed that grass that is 100% green has a legume and perennial grass composition within the range of 20-30% legumes and 60-70% grass, and that the oldest leaf of the dominant grass has not yet senesced. energy content greater than 11.5 MJ ME/kg DM. Figure 2 below provides an indication of the energy decline as temperate pastures mature.

Figure 2: A guide to digestibility decline as temperate pastures mature

Kilde: NSW PROGRAZE Manual, NSW Agriculture