Polysulphate Chinese Cabbage Trial in China
18
Hainan, China 2015
18
Key Conclusions
Polysulphate application is highly profitable for Chinese cabbage farmers. In this trial applying Polysulphate at 375 kg/ha increased crop yield by up to 18%, and increased the net profit by 2,978 USD/ha.
Objective
To investigate the effect of increasing rates of Polysulphate on the yield, growth parameters, concentrations of soil nutrients and soil pH after harvest of Chinese cabbage (Brassica rapa pekinensis).
Trial Details
Trial station
Hainan, China
Product
Granular Polysulphate
Assessments
Yield, growth parameters, soil nutrients after harvest, and soil pH after harvest
Treatments
This randomized block trial consisted of 4 replicates with 5 treatments. In all treatments, nitrogen, phosphorus, and potassium were applied according to farmers’ traditional practice: 450 kg/ha of compound fertilizer (15-15-15) + 7.5 t/ha of organic fertilizer applied as base-fertilizer. Four treatments consisted of increasing rates of Polysulphate: 375, 750, 1,125 and 1,500 kg/ha. The control treatment received the same NPK and organic fertilizer + 300 kg/ha calcium cyanamide, but no Polysulphate was applied.
Treatment | NPK (15-15-15) | Organic fertilizer | Polysulphate | Calcium cyanide |
---|---|---|---|---|
kg/ha | t/ha | kg/ha | kg/ha | |
T0 | 450 | 7.5 | 0 | 300 |
T375 | 450 | 7.5 | 375 | 0 |
T750 | 450 | 7.5 | 750 | 0 |
T1125 | 450 | 7.5 | 1,125 | 0 |
T1500 | 450 | 7.5 | 1,500 | 0 |
Treatments
This randomized block trial consisted of 4 replicates with 5 treatments. In all treatments, nitrogen, phosphorus, and potassium were applied according to farmers’ traditional practice: 450 kg/ha of compound fertilizer (15-15-15) + 7.5 t/ha of organic fertilizer applied as base-fertilizer. Four treatments consisted of increasing rates of Polysulphate: 375, 750, 1,125 and 1,500 kg/ha. The control treatment received the same NPK and organic fertilizer + 300 kg/ha calcium cyanamide, but no Polysulphate was applied.
Treatment | NPK (15-15-15) | Organic fertilizer | Polysulphate | Calcium cyanide |
---|---|---|---|---|
kg/ha | t/ha | kg/ha | kg/ha | |
T0 | 450 | 7.5 | 0 | 300 |
T375 | 450 | 7.5 | 375 | 0 |
T750 | 450 | 7.5 | 750 | 0 |
T1125 | 450 | 7.5 | 1,125 | 0 |
T1500 | 450 | 7.5 | 1,500 | 0 |
Results
- Potassium, Mg and Ca concentrations in soil after harvest were increased in the Polysulphate treatments when compared to the control.
- Polysulphate application increased soil pH after harvest from 4.9 (control) up to 5.28 (1,500 kg Polysulphate/ha).
- Application of Polysulphate increased the stem diameter and root weight of Chinese cabbage significantly.
- Polysulphate application significantly increased the yield. The highest yields were obtained when Polysulphate was applied at a rate of 375 and 750 kg/ha.
- Polysulphate application was highly profitable. The highest additional net profit (2,978 USD/ha) was obtained when Polysulphate was applied at a rate of 375 kg/ha.
Polysulphate | Soil pH | Available K | Exchangeable Mg | Exchangeable Ca |
---|---|---|---|---|
kg/ha | mg/kg | mg/kg | mg/kg | |
0 | 4.88 | 124.4 | 90.2 | 772.6 |
375 | 4.99 | 145.0 | 126.9 | 1,142.6 |
750 | 5.06 | 218.2 | 132.4 | 1,886.6 |
1,125 | 5.03 | 199.0 | 180.3 | 1,063.1 |
1,500 | 5.28 | 286.4 | 208.5 | 2,138.3 |
* Different letters above bars indicate significant differences among treatments (p<0.05).