The 2020 Pasture Profit Index (PPI) has just been released by Teagasc and the Department of Agriculture, Food and the Marine (DAFM).
Once again, AberGain is the leading late tetraploid and AberChoice is the leading late diploid with AberClyde and AberMagic, the leading intermediate tetraploid and diploid, respectively. AberClyde is also the highest ranked variety overall for 2020, with a total PPI value of €205 per ha/year.
Grass evaluation trials
Before examining the PPI index, it is useful to understand the grass evaluation trials. In Ireland, DAFM conducts the Recommended List trials. For a variety to be published on the Recommended List and the PPI it undergoes a minimum of 4 years of trials. Each variety is evaluated over a minimum of 2 sowing years and 2 harvest years per sowing year. There are 5 trials sites across the country (Donegal, Galway, Kildare, Kilkenny and Cork), with each variety sown at each site. Only varieties that demonstrate better than average performance are then published on the list. There are 2 new varieties added to the 2020 list, with 4 varieties removed from the list this year.
Understanding the PPI
The PPI is an economic index for ranking grass varieties. It uses a model to determine the economic value of each of the key traits in grass production terms – spring, summer and autumn DM yield, quality, silage DM yield (based on 1st and 2nd cut yields) and persistency. The economic value for each trait is applied to measured performance of a variety in the Recommended List trials and the sum of all the values then determines the total PPI value of a variety in € per ha/year.
Seasonal DM Yield
Reported as spring, summer and autumn DM yield in the PPI, this information presents the yield performance of each variety across these three time periods. Extra grass in the spring is of highest value in the index, followed by autumn, with extra grass grown in the mid-season period being of the lowest value. The difference between the best and worst variety for spring growth on the 2020 PPI is €107 per ha/year. Compared to summer growth, the difference between the best and worst is only €34 per ha/year, and in autumn the difference is €48 per ha/year.
Quality is measured across the months of April, May, June and July. AberGain is the highest variety overall for quality at €52 per ha/year. The lowest variety for quality is Nifty at €34 per ha/year; a difference of €86 per ha/year. Quality is a hugely important trait as it has the potential to deliver big differences at farm level.
The small variation between the best and worst varieties for persistency in the PPI demonstrates that there are small differences between varieties in persistency terms. Soil fertility and management are the biggest influencers of sward persistency.
Whilst AberClyde is the highest-ranked variety overall for 2020, AberGain is the leading late tetraploid (€192 per ha/year) and has held this position consistently over the last number of years. AberGain is a proven variety on Irish farms, with excellent seasonal and total growth and has the highest quality of all varieties on the PPI. AberChoice is the leading late diploid at €176 per ha/year. AberChoice and Drumbo are the only 2 late diploids with positive values for quality; a proven indicator of palatability and high grass utilisation. AberMagic is yet again the leading intermediate diploid at €187 per ha per year.
When selecting your grazing mixtures for 2020, focussing on varieties with strong PPI values and high quality are essential to maximise the return on your investment. Choosing varieties with positive values for quality will help ensure you have a palatable mixture, which will support higher animal intakes and animal performance. Varieties with good spring and autumn growth are also desirable to increase grass availability at these key points in your grazing season.
A maximum of three to four varieties in a mix is ideal as if you have too many varieties, some will be included at a low rate and the benefit of that variety over an acre would be questionable. The recommended sowing rate for perennial ryegrass mixtures is 14kg/acre.
From 1st January 2020, farms in derogation must include 0.6 kg clover per acre or 1.0 kg coated clover per acre when reseeding. White, red or a mixture of both white and red clover is acceptable. Remember to use a clover-safe post-emergence spray after sowing clover.