Swards can be measured using the following techniques:

1) Cutting and weighing

• Quadrat (0.5 x 0.5m), shears, weighing scales and plastic bag are required
• Place the quadrat on an area that is representative of the paddock or take a few quadrat cuts per paddock
• Clip the grass in the quadrat to the target post grazing height with the shears
• Place all the clipped herbage in the bag and weigh
• Estimate herbage dry matter percentage and use the following calculation:
  • Weight of grass (kg) x grass DM% x 40,000 = kg DM/ha in the paddock

2) Rising platemeter

• The rising platemeter measures the compressed height of a sward, each of the mechanism ‘clicks’ represents 0.5cm of compressed height
• Record the start number on your platemeter before taking heights in a paddock
• Target 30 heights across the entire paddock in a ‘W’ pattern to give accurate representation of a paddock
• Record the end number after taking your heights, subtract your start number and then divide by 2 to get your compressed sward height in cm, then divide by 30 if you took 30 height measurements
• Compressed sward height = (start number-end number)/2 ÷ number of heights taken
• Subtract your target post grazing height (e.g. 4cm) from the sward height of each paddock
• Multiply the figure you get by 300 as there is typically 300kg DM/ha per cm in sheep swards
• Automated platemeters (e.g. Grasshopper) can calculate sward height automatically and transfer data to online database or smartphone

3) Sward Stick

• Easy to use and low investment
• Use gauge on side to show when swards are grazed out, growing, should be grazed or have covers too heavy for grazing

How to use data:

• Manually calculate the whole farm cover together with animal demand, days grazing ahead, pasture growth rate from last measurement etc. or use an online application e.g. PastureBase Ireland or Agrinet
• Average farm cover is calculated by multiplying each paddock cover by its area, totalling all paddocks and then dividing by total area
• Animal demands varies depending on age, stage of lactation etc. as a guide daily intake for ewes rearing twins will range from 2.4 kg DM from 1 week post lambing to 3.4 kg at 7 weeks post lambing
• Pasture management decision support tools (e.g. PastureBase Ireland, Agrinet) automatically calculate growth rates, average farm cover, days grazing ahead, stocking rate and animal demand when all paddock covers and stock information are uploaded. Pasture management decision support tools create reports to show total pasture production for each paddock on the farm