Polysulphate Sweet Potato Trial in USA
7
Kenly, North Carolina, USA 2019
7
Key Conclusions
Compared with the GSP, using a blend with Polysulphate increased sweet potato yield by 7% or approximately 4.9 bushels/acre.
Objective
To compare the effect on sweet potato (Ipomoea batatas) yield of replacing the grower standard fertilizer blend with a blend which contains Polysulphate, in North Carolina, USA.
Trial Details
Trial station
Kenly, North Carolina, USA
Crop
Potato
Product
Polysulphate Granular
Assessments
Sweet potato yield
Treatments
Farmers’ practice consisted of a blend of DAP, MOP, and potassium-magnesium sulfate, while the Polysulphate treatment consisted of a blend of DAP, MOP and Polysulphate.
Treatment | N | P2O5 | K2O | S | Mg | Ca |
---|---|---|---|---|---|---|
kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | |
Farmer's blend | 23 (21) | 61 (54) | 225 (201) | 17 (15) | 8 (7) | - |
Blend with Polysulphate | 26 (23) | 65 (58) | 224 (200) | 57 (51) | 10 (9) | 37 (33) |
These blends were applied two weeks after setting. Both treatments had liquid UAN (urea ammonium nitrate) side–dressed at mid-season.
Treatments
Farmers’ practice consisted of a blend of DAP, MOP, and potassium-magnesium sulfate, while the Polysulphate treatment consisted of a blend of DAP, MOP and Polysulphate.
Treatment | N | P2O5 | K2O | S | Mg | Ca |
---|---|---|---|---|---|---|
kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | kg/ha (lbs/acre) | |
Farmer's blend | 23 (21) | 61 (54) | 225 (201) | 17 (15) | 8 (7) | - |
Blend with Polysulphate | 26 (23) | 65 (58) | 224 (200) | 57 (51) | 10 (9) | 37 (33) |
These blends were applied two weeks after setting. Both treatments had liquid UAN (urea ammonium nitrate) side–dressed at mid-season.
Results
-
- Compared with the GSP, using a blend with Polysulphate increased sweet potato yield by 7% or approximately 12 bushels/ha (approximately 4.9 bushels/acre).
- The results showed that with equal amounts of N, P, and K there is a benefit from choosing Polysulphate fertilizer due to the higher rate of plant-available sulfur and calcium. Also, the prolonged availability of the nutrients from Polysulphate may contribute to the enhanced yields.