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Copy link Polysulphate Cabbage Trial in Vietnam
64
Me Linh district, Hanoi, Vietnam 2016
64
Key Conclusions
Fertilizing cabbage with a combination of Polysulphate and MOP increases cabbage head size, marketable cabbage yield, and increases profit by up to 64%.
Objective
To evaluate the agronomic efficiency of Polysulphate on yield, quality, and economic returns of winter cabbage on degraded soils in Northern Vietnam, demonstrating the advantages of using Polysulphate as an alternative to MOP.
Trial Details
Trial station
Me Linh district, Hanoi, Vietnam
Product
Granular Polysulphate
Assessments
Yield, canopy diameter, plant weight, and head diameter and height
Treatments
The experiment included 6 treatments, with 4 replications in a randomized complete block design. The treatments differed in K rate (from 0-120 kg K2O/ha) and source: muriate of potash (KCl) and Polysulphate.
- The farmers’ practice (K150+0) included a high K rate, all of which was applied through MOP, and served to compare with the other treatments. The control K0 did not include any K application.
- In treatments K60+0 and K30+30, the K rate was reduced to 60 kg K2O/ha, applied solely through MOP or through a combination of MOP and Polysulphate, respectively.
- In treatments K45+45 and K60+60, K application rates rose to 90 and 120 kg K2O/ha, respectively, while maintaining a 1:1 ratio between MOP and Polysulphate as the sources of K2O.
All treatments received farmyard manure (FYM) at 15 t/ha, 180 kg N/ha (urea) and 80 kg P2O5/ha (superphosphate). Fertilizers were applied at 5 stages: pre-planting (100% FYM, 50% P and 20% K), and irrigated dressings at 10 (30% N), 30 (30% N, 30% P and 30% K), 40 (20% N and 25% K), and 50 days after planting (20% N and 25% K).
| Treatment | FYM | Nitrogen (N) | Phosphorus (P2O5) | Potassium (K2O) | |
|---|---|---|---|---|---|
| MOP | Polysulphate | ||||
| t/ha | kg/ha | kg/ha | kg/ha | kg/ha | |
| K150+0 | 15 | 180 | 80 | 150 | 0 |
| K0 | 15 | 180 | 80 | 0 | 0 |
| K60+0 | 15 | 180 | 80 | 60 | 0 |
| K30+30 | 15 | 180 | 80 | 30 | 30 |
| K45+45 | 15 | 180 | 80 | 45 | 45 |
| K60+60 | 15 | 180 | 80 | 60 | 60 |
| FYM = farmyard manure, FP = Farmers’ practice. | |||||
Treatments
The experiment included 6 treatments, with 4 replications in a randomized complete block design. The treatments differed in K rate (from 0-120 kg K2O/ha) and source: muriate of potash (KCl) and Polysulphate.
- The farmers’ practice (K150+0) included a high K rate, all of which was applied through MOP, and served to compare with the other treatments. The control K0 did not include any K application.
- In treatments K60+0 and K30+30, the K rate was reduced to 60 kg K2O/ha, applied solely through MOP or through a combination of MOP and Polysulphate, respectively.
- In treatments K45+45 and K60+60, K application rates rose to 90 and 120 kg K2O/ha, respectively, while maintaining a 1:1 ratio between MOP and Polysulphate as the sources of K2O.
All treatments received farmyard manure (FYM) at 15 t/ha, 180 kg N/ha (urea) and 80 kg P2O5/ha (superphosphate). Fertilizers were applied at 5 stages: pre-planting (100% FYM, 50% P and 20% K), and irrigated dressings at 10 (30% N), 30 (30% N, 30% P and 30% K), 40 (20% N and 25% K), and 50 days after planting (20% N and 25% K).
| Treatment | FYM | Nitrogen (N) | Phosphorus (P2O5) | Potassium (K2O) | |
|---|---|---|---|---|---|
| MOP | Polysulphate | ||||
| t/ha | kg/ha | kg/ha | kg/ha | kg/ha | |
| K150+0 | 15 | 180 | 80 | 150 | 0 |
| K0 | 15 | 180 | 80 | 0 | 0 |
| K60+0 | 15 | 180 | 80 | 60 | 0 |
| K30+30 | 15 | 180 | 80 | 30 | 30 |
| K45+45 | 15 | 180 | 80 | 45 | 45 |
| K60+60 | 15 | 180 | 80 | 60 | 60 |
| FYM = farmyard manure, FP = Farmers’ practice. | |||||
Results
- Plants of all treatments with combined Polysulphate and MOP had significantly greater canopy diameter compared to the MOP-applied plants, and K0 plants displayed the smallest diameter.
- The response of head dimensions, the total and marketable cabbage yields were lowest at K0, intermediate under MOP, and significantly higher under MOP and Polysulphate combinations.
- When applying combined MOP and Polysulphate, about 20% of the currently recommended K dose can be avoided, while still producing a 15% increase in the marketable yield.
- Using a combination of Polysulphate and MOP, K application dose was reduced from 150 to 120 kg K2O/ha, while the profit grew by 64%.
Polysulphate fertilizer increased cabbage yield by 61.5%.
Adding Polysulphate to the fertilizer regime increased profit by 64%.
* From research funded by the International Potash Institute www.ipipotash.org.
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