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Copy link Polysulphate Maize Trial in Vietnam
13
Vinh Phuc Province, Vietnam 2016
13
Key Conclusions
Trial shows the advantages of using Polysulphate as a substitute for MOP, increasing yield by 13%, and doubling the farmers’ profits compared to the farmer’s usual practice.
Objective
To evaluate the agronomic efficiency of Polysulphate on yield, quality, and economic returns of winter maize (Zea mays) on degraded soils in Northern Vietnam, and to record the advantages of using Polysulphate as an alternative to MOP.
Trial Details
Trial station
Vinh Phuc Province, Vietnam
Crop
Maize
Product
Granular Polysulphate
Assessments
Yield, plant height, number of leaves, and occurrence of pests and diseases
Treatments
This experiment included 6 treatments, with 4 replications in a randomized complete block design. The farmers’ usual practice (K120+0) of a high K rate applied through MOP, was compared with 5 other treatments. The control (K0) had no K applied. Treatments K60+0 and K30+30 received 60 kg/ha K2O, applied solely through MOP or through a combination of MOP and Polysulphate, respectively. In treatments K45+45 and K60+60, 90 and 120 kg/ha K2O was applied respectively, while maintaining a 1:1 ratio between MOP and Polysulphate as the sources of K2O.
All treatments received 10 t/ha farmyard manure, 180 kg/ha N and superphosphate at 90 kg/ha P2O5. The mineral fertilizers were applied before sowing (30% N, 100% P, 40% K and 40% Polysulphate), at 4 to 6 leaves (40% N), and at pollination (30% N, 60% K and 60% Polysulphate).
| Treatment | FYM | N | P2O5 | K2O | |
|---|---|---|---|---|---|
| KCl | Polysulphate | ||||
| t/ha | kg/ha | kg/ha | kg/ha | kg/ha | |
| K120+0 | 10 | 180 | 90 | 120 | 0 |
| K0 | 10 | 180 | 90 | 0 | 0 |
| K60+0 | 10 | 180 | 90 | 60 | 0 |
| K30+30 | 10 | 180 | 90 | 30 | 30 |
| K45+45 | 10 | 180 | 90 | 45 | 45 |
| K60+60 | 10 | 180 | 90 | 60 | 60 |
Treatments
This experiment included 6 treatments, with 4 replications in a randomized complete block design. The farmers’ usual practice (K120+0) of a high K rate applied through MOP, was compared with 5 other treatments. The control (K0) had no K applied. Treatments K60+0 and K30+30 received 60 kg/ha K2O, applied solely through MOP or through a combination of MOP and Polysulphate, respectively. In treatments K45+45 and K60+60, 90 and 120 kg/ha K2O was applied respectively, while maintaining a 1:1 ratio between MOP and Polysulphate as the sources of K2O.
All treatments received 10 t/ha farmyard manure, 180 kg/ha N and superphosphate at 90 kg/ha P2O5. The mineral fertilizers were applied before sowing (30% N, 100% P, 40% K and 40% Polysulphate), at 4 to 6 leaves (40% N), and at pollination (30% N, 60% K and 60% Polysulphate).
| Treatment | FYM | N | P2O5 | K2O | |
|---|---|---|---|---|---|
| KCl | Polysulphate | ||||
| t/ha | kg/ha | kg/ha | kg/ha | kg/ha | |
| K120+0 | 10 | 180 | 90 | 120 | 0 |
| K0 | 10 | 180 | 90 | 0 | 0 |
| K60+0 | 10 | 180 | 90 | 60 | 0 |
| K30+30 | 10 | 180 | 90 | 30 | 30 |
| K45+45 | 10 | 180 | 90 | 45 | 45 |
| K60+60 | 10 | 180 | 90 | 60 | 60 |
Results
- Zero K application led to a substantial loss of yield and profit.
- Combinations of MOP and Polysulphate gave rise to significantly higher fodder yields, in grains as well as husks and corncobs.
- K rates of 60 or 90 kg/ha K2O are sufficient to obtain reasonable maize yields.
- Economic analysis shows MOP with Polysulphate at rate of 90 kg/ha K2O was the most profitable practice (2.2 times more profitable than the farmer’s usual practice of MOP alone).
- Rate of damage from pests (corn borer and corn aphid), and diseases (sheath blight and stalk rot) was lower among the Polysulphate-treated plants.
Polysulphate fertilizer increased maize yield by up to 13%.
Maize grown with Polysulphate was 2.2 times more profitable than the farmer’s usual practice.
From research funded by the International Potash Institute www.ipipotsh.org
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