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Copy link Polysulphate Alfalfa Trial in France
12
Vésigneul-sur-Marne, France 2020
12
Key Conclusions
Throughout the experiment, the Polysulphate fertilizer alfalfa yielded more than the control plot, increasing alfalfa yield by 12% in the highest yield treatment which supplied approximately 10% of the total potassium as Polysulphate in addition to supplying S, Ca, and Mg.
Objective
To evaluate Polysulphate, in combination with KCl, as a K and secondary macronutrients source for rainfed alfalfa, and to examine the response of both yield and quality to increasing proportions of Polysulphate.
Trial Details
Trial station
Vésigneul-sur-Marne, France
Crop
Alfalfa
Product
Polysulphate Granular
Assessments
Alfalfa yield and feed quality.
Treatments
- This alfalfa trial consisted of three replications, in a randomized complete block design.
- Four different treatments were established with combinations of 2 different sources of potassium, potassium chloride (KCl) and Polysulphate, at a similar K dose of 300 kg K2O/ha, with 4 different proportions: all K from KCl, and 10%, 20% and 40% of the K from Polysulphate.
- Polysulphate Granular was used for the two lower rates of product, while Polysulphate Standard was used for the highest rate.
- A control was established which received no additional nutrient supply.
- The alfalfa was harvest in 6 cuts: 25 May 2019, 1 July 2019, 23 August 2019, 13 May 2020, 3 July 2020, and 20 August 2020.
| Treatment | Fertilizer rate | Nutrient rate | |||||
|---|---|---|---|---|---|---|---|
| MOP (KCl) | Polyhalite | K2O | Mg | S | Ca | ||
| kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | ||
| Control | 0 | 0 | 0 | 0 | 0 | 0 | |
| KCl | 446 | 0 | 268 | 0 | 0 | 0 | |
| Polysulphate 200 | 401 | 178 | 268 | 7 (6) | 38 (34 0 | 23 (20) | |
| Polysulphate 405 | 361 | 361 | 268 | 14 (13) | 78 (69) | 46 (41) | |
| Polysulphate 800 | 277 | 714 | 268 | 29 (26) | 154 (137) | 91 (82) | |
Treatments
- This alfalfa trial consisted of three replications, in a randomized complete block design.
- Four different treatments were established with combinations of 2 different sources of potassium, potassium chloride (KCl) and Polysulphate, at a similar K dose of 300 kg K2O/ha, with 4 different proportions: all K from KCl, and 10%, 20% and 40% of the K from Polysulphate.
- Polysulphate Granular was used for the two lower rates of product, while Polysulphate Standard was used for the highest rate.
- A control was established which received no additional nutrient supply.
- The alfalfa was harvest in 6 cuts: 25 May 2019, 1 July 2019, 23 August 2019, 13 May 2020, 3 July 2020, and 20 August 2020.
| Treatment | Fertilizer rate | Nutrient rate | |||||
|---|---|---|---|---|---|---|---|
| MOP (KCl) | Polyhalite | K2O | Mg | S | Ca | ||
| kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | kg/ha (lbs/A) | ||
| Control | 0 | 0 | 0 | 0 | 0 | 0 | |
| KCl | 446 | 0 | 268 | 0 | 0 | 0 | |
| Polysulphate 200 | 401 | 178 | 268 | 7 (6) | 38 (34 0 | 23 (20) | |
| Polysulphate 405 | 361 | 361 | 268 | 14 (13) | 78 (69) | 46 (41) | |
| Polysulphate 800 | 277 | 714 | 268 | 29 (26) | 154 (137) | 91 (82) | |
Results
- Over the whole duration of the experiment (2-years), the alfalfa fertilized with Polysulphate and KCl yielded approximately 0.7 ton/A more than the crop fertilized only with MOP, and approximately 1.4 ton/A a more than control treatment which received no MOP.
- A clear trend was observed in all cuts – especially in the second year – with improvements in the quality parameters (protein contents) of the alfalfa fertilized with Polysulphate (data not shown)
Polysulphate fertilizer increased alfalfa yield by 12% compared to the control.
Different letters indicate significant differences at p < 0.05. Error bars are SD.
* From research funded by the International Potash Institute www.ipipotash.org
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