Collecting Pasture Cuts for Dry Weights with Survey123 App

Instructions on how to perform pasture cuts and enter this information into survey123 App. Also provides instructions on how to dry pasture to determine the Dry Matter %.

Doing Pasture Cuts for Dry Weights

You will need the following:

- 0.25sqm quadrat for most northern pastures and a 0.1sqm quadrat for most southern improved pastures

- plastic bags for doing “wet weights”

- paper bag for oven drying sub-samples of pasture

- electric clippers or hand shears.

- Permanent marker

- Scales

STEPS

1. Open the survey123 App. When you are at the first quadrat site, hit ‘Collect’, then enter your email address, property, paddock & select measurement type ('Pasture Cuts')

   

2. Place the quadrat on pasture then take a photo looking along the intended direction of your transect & a vertical reference photo of the quadrat

3. Cut the pasture as close to ground level as possible and place in paper bag. Number the bag in order of quadrats. Estimate DM% and ground cover %. Hit the + button and repeat the process for the other quadrats (Min 5 total, 10m apart, 50m transect)

   
4. At the end of the transect, enter dominant pasture species, palatable %, Palatable 3Ps, Green Fraction etc.

5. Once back at the car, weigh the samples as soon as possible after you have cut them to avoid them drying out. Don’t forget to “zero” the scales with the paper bag to remove the bag weight. Enter this info into the app under 'Wet Weight.'

• Weigh and record the quadrat samples.

• 0.25sqm quadrat - grams x 40 = kg/ha

• 0.1sqm quadrat - grams x 100 = kg/ha

• Remember these are “wet weights” and must be adjusted for the moisture content to derive dry matter (DM%)

6. Save the survey to drafts, using 'Save to Drafts'

7. Take a sample from each bag and put in one paper bag. Weigh this bag and label with 'Property, date, survey ID, grass type and weight'. This is your 'Dry Matter Sample' which will be oven dried to calculate DM%.

WHEN YOU GET HOME:

1. Place in an oven at 80degC for minimum of 12 hours. Weigh again and place back in the oven for another 2hrs and weigh again. You can also use a microwave (see ‘Silage Note No. 7’).

2. If the weight hasn’t changed it is ready to calculate DM content

• DM% = dry weight / wet weight

• Hay would normally have a DM% of ~85%

• Actively growing cereal crops are likely to be ~30-40% DM%

• Partially cured perennial pastures might be 50-70% DM%.

• The message here is that DM% varies substantially and has a huge effect on estimates.

For most properties you should be able to collate enough cuts and photos across your major pasture types and biomass levels in a morning. Complete the oven drying overnight, compile your photos against the DM weights into a document, and you have your own library to refer to, and to provide staff with a local reference.