Field-scale trials have reportedly shown improvements in both potato output and marketable yield following treatments with ICL’s Polysulphate and PotashpluS.
“The trials bear out findings from previous years of the benefits of our products for the crop,” said ICL agronomist Scott Garnett.
On a North Yorkshire farm, the variety Brooke was established on sandy loam soil. The spilt field trial sought to assess the potential for both treatments to replace GMOP.
Three rates of Polysulphate were applied just before planting; 100kg, 200kg and 300kg per hectare. PotashpluS was applied at 895kg per hectare. These were compared with a control of granular muriate of potash, applied at 550kg per hectare. Potash products were applied a month before establishment.
| Nitrogen (kg/ha) | Phosphate (kg/ha) | Potassium (kg/ha) | Magnesium (kg/ha) | Calcium (kg/ha) | Sulphur (kg/ha) | |
| Control | 200 | 170 | 330 | 40 | 0 | 96 |
| PotashpluS (895kg/ha) | 200 | 170 | 330 | 43 | 52 | 215 |
| Polysulphate (100kg/ha) | 200 | 170 | 330 | 43 | 17 | 138 |
| Polysulphate (200kg/ha) | 200 | 170 | 330 | 43 | 34 | 174 |
| Polysulphate (300kg/ha) | 200 | 170 | 330 | 43 | 51 | 210 |
The trials were harvested using five 2m replicated digs from each treatment and the total yield was recorded along with four graded outputs. All treatments increased total and marketable yield compared to the control, with the best result achieved from Polysulphate applied at 100kg/ha.
The second trial in North Lincolnshire used the variety Maris Piper, grown on sandy loam soil, with a soil analysis of potassium – potassium – index 2; magnesium – index 5; phosphate – index 2 and pH 7.1.
This trial explored the effect of sulphur on potato production using Polysulphate as the sole source. An application of 200kg/ha was added to the standard farm practice.
| Nitrogen (kg/ha) | Phosphate (kg/ha) | Potassium (kg/ha) | Magnesium (kg/ha) | Calcium (kg/ha) | Sulphur (kg/ha) | |
| Farm Practice | 140 | 119 | 225 | 0 | 0 | 0 |
| Farm Practice with Polysulphate | 140 | 119 | 226 | 12 | 34 | 96 |
In this trial, Polysulphate boosted marketable yield by 18% compared to the control.
These confirm results gained in previous years and highlight the economic benefit to be gained from applying it, as well as the importance of sulphur to the potato crop.