Farming News - NAAC Field Trials: Seed Size Matters
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NAAC Field Trials: Seed Size Matters
New independent field trials done this year by SGS*, on behalf of the National Association of Agricultural Contractors (NAAC), show that bigger seed sizes result in significantly higher vigour, emergence, crop height and rooting weight. These trials are now being taken to harvest when final yield results will also be analysed.
These results are particularly important this coming autumn and spring as risk management will be key to growers. As input costs continue to remain at breath-taking highs, with no signs of abating, a tight juggling act will be needed to manage crop establishment and agronomy costs and cash flow, whilst commodity prices remain a relative unknown next year.
Farm saving seed will be an obvious choice for many but then it will be vital that every seed put in the ground is given the optimum opportunity to grow and reach a productive yield. Integrated farm management techniques will help growers to minimise the application of nutrients and plant protection products, but the seed itself will remain the building blocks of the following crop.
Whilst NAAC processors suspected that seed size matters, there was a lack of independent research and when initial processor trials in Cornwall indicated a link, this led to the NAAC commissioning scientific glass house trials of winter wheat and spring barley in 2020 to gather evidence.
Initial results (below) support the seed processors long held belief that bigger seeds demonstrate improved germination, emergence and vigour.
| Table 1: Winter Wheat | % Germination | % Emergence | Vigour |
| Fraction 1 : TWG 60 | 85 | 90 | 96 |
| Fraction 2 : TWG 40 | 75 | 90 | 95 |
| Fraction 3 : TWG 28 | 70 | 80 | 81 |
| Fraction 4 : TWG 16 | 32 | 24 | 30 |
| Table 2: Spring Barley | % Germination | % Emergence | Vigour |
| Fraction 1 : TWG 50 | 92 | 92 | 94 |
| Fraction 2 : TWG 36 | 86 | 88 | 87 |
| Fraction 3 : TWG 26 | 80 | 80 | 80 |
| Fraction 4 : TWG 15 | 70 | 70 | 70 |
TWG = Thousand grain weight
The next step was to take the trials out to the field. In Autumn 2021, the NAAC commissioned a fractional seed size field trial with SGS, who planted the seed and monitored crop growth, taking the final crop to harvest for a yield response measurement.
Winter wheat and spring barley were sorted by size into four different fractions, varying from >2.8mm and <2.22mm in size, and drilled in field conditions. The results to date (June 2022), are showing that larger seeds, which receive the same inputs pre- and post- drilling, grow significantly better than smaller seeds.
Trial results are proving that sorting seed, to select the largest fraction, will significantly increase:
- Vigour
- Emergence
- Crop Height
- Rooting Weight.
It is therefore critical, if farm saving, to get the seed sorted by size. NAAC field trial results statistically demonstrate the importance of having seed processed to ensure that each drilled seed is selected for its optimal potential, so future benefits of applying fertiliser and other inputs can be maximised.
Commenting, Richard Jones, NAAC Seed Section Chairman said, ‘Our results clearly show the benefits of using quality processed farm saved seed, selected for size to balance cost and output. By selecting the largest seed sizes, growers can help their crop get well-established and ahead to potentially benefit from higher yields in the final harvest.’
When a mobile seed processor is employed the waste fraction is also left on the farm, to be sold or used as feed. This way there is no waste, saving money, whilst selecting the best seed for cropping.
These scientific trials demonstrate the practice of barn dipping seed, without screening and gravity selection, is not a proven route to success and that money will be well spent getting farm saved seed cleaned and processed.
*SGS is the world’s leading inspection, verification, testing and certification company. https://www.sgs.co.uk/en-gb/agriculture-food/seed-and-crop