Don’t rely on average thousand grain weight to set your drill
ANY cereals drilled in March 2013 were drilled into a ‘ perfect storm’. The seed was grown during 2012, which was the worst summer for 50 years in terms of ear disease pressure.
Then it was sown into what turned out to be the coldest spring i n 50 years, which extended emergence. It was a wonder that any of those seeds grew at all and just as well the summer came as it did.
Crop students in Kildalton College found that the average establishment was 70pc in the March-drilled Department of Agriculture cereal variety trials.
All of the seed drilled in these plots had a germination test of over 85pc, but a combination of seedling diseases, pest attacks and abnormally cold weather meant that only seven out of 10 seeds sown made a plant.
It was the same story at farm level. Thin crops were one of the main topics at the all the Teagasc spring tillage walks that I attended. So what lessons can we learn from 2013? Germination and establishment To start with basics, the difference between germination and establishment needs to be clearly understood. Germination is the test that either you or the seed merchant pays for on the seed.
If your seed has 90pc germination, then nine out of 10 seeds you drill will ‘ s t r i ke’ and produce a small shoot. In Ireland, only seed with a germination rate of at least 85pc can be sold. Establishment is the number of seeds drilled that make a full plant.
You can only count or assess establishment once the plants have come above ground. The establishment score is therefore a combination of the germination test and any losses after drilling due to field conditions, pest attack, stones and so on.
The difference be tween germination and establishment are usually small, but in a bad season, such as 2013, they were quite significant and accounted for a lot of the variation in yield. Seed health, quality and size The Department’s seed certification laboratory indicates that germination percentages of spring cereal seed tested to date are above average and disease levels are below average.
The usual care should be taken to consider any deterioration in seed quality during drying or storage on farm. If you stored seed on farm, from last spring, I would be slow to advise you to use it and at the ver y least ensure it is well tested before drilling.
In general, the thousand grain weight (TGW) is high in seed lots this year. While this usually implies good germination, vigour and low levels of disease, it is still advisable to have home-saved seed tested.
Remember that you are legally obliged to pay any r oyalti es t hat ari s e from home-saved seed. The Plant Royalty Development Office (PVDO) has a ver y handy calculator on their website that will do this sum for you (www.pvdo.ie). It is illegal to sell or barter home-saved seed.
There can be a big variation of TGW, even within varieties.
Some variety trial data that I saw this year had a 10-point gap between the lowest and highest TGW sample. However, it usually falls within a band of plus or minus three TGW points.
The key message from this is not to rely on average variety TGW to set your drill. Ask your merchant for the TGW or test home-saved seed. Over the past few years, the TGW has often been printed on seed bags.
This is a welcome development by the seed trade and hopefully it will be extended to all certified seed in the future.
Certified seed offers growers high germination capacity, purity of sample, minimum levels of weed seeds, and treatment against seed-borne diseases.
The Department has produced a comprehensive guide on seed cer tification which is available from their website under the Crops section.