Trials at field scale have proven improvements in both potato output and marketable yield from 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.

In North Yorkshire a crop of the variety Brooke was grown on a sandy loam soil. The split field trial sought to assess the potential for Polysulphate or PotashpluS to replace GMOP. Three rates of Polysulphate were applied – 100, 200 and 300kg/ha. PotashpluS was applied at 895kg/ha. These treatments were compared with a control of granular muriate of potash applied at 550kg/ha.

Polysulphate was applied just before planting, while potash products were applied a month earlier. These treatments applied nutrients as follows:

	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. Total yield was recorded along with four graded outputs.

All treatments increased total and marketable yield compared to the control. However, the best result was achieved from Polysulphate applied at 100kg/ha.

The second trial in North Lincolnshire used the variety Maris Piper, again grown on a sandy loam with a soil analysis of potassium – index 2; magnesium – index 5; phosphate – index 2 and pH 7.1.

This split field trial explored the effect of sulphur on potato production using Polysulphate as the sole source of S. An application of 200kg/ha of Polysulphate was added to the standard farm practice. Giving total nutrients as follows:

	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 Polyphosphate boosted marketable yield by 18% compared to the control. 

These results confirm results gained in previous years and highlight the economic benefit to be gained from applying Polysulphate and the importance of sulphur to the potato crop.