Polysulphate Coffee Trial in Vietnam

11.5

Yield Increase
Supplementing NPK with Polysulphate improved yield (by 11.5%) and quality of coffee crop, increasing net profits by 14%.

Bao Lam district, Lam Dong Province, Vietnam
2015

Trail

11.5

Yield Increase

Key Conclusions

Supplementing NPK with Polysulphate fertilizer increased coffee yield by 11.5%, produced superior quality fruit (indicated by the increased proportion of size A cores), and increased net profit by 14%.

Objective

To evaluate the efficacy of Polysulphate to increase coffee (<em>Coffea robusta</em> yield in Vietnam, and to evaluate the cost-effectiveness of applying fertilizers in split doses compared to the traditional practice of a single application of urea, KCl, and fused Ca, Mg, and P.

Trial Details

Trial station

Bao Lam district, Lam Dong Province, Vietnam

Crop

Coffee

Product

Granular Polysulphate

Assessments

Yield, fruit weight, and A-size core

Treatments

This completely randomized block trial comprised 3 replications, each with 3 treatments:

  1. Traditional practice/control: single application of urea, KCl, and fused Ca, Mg, and P.
  2. Commercially available compound fertilizers (with S but no Ca or Mg).
  3. Same as as the commercially available compound treatment (2. above) but supplemented with Polysulphate.

In the 2 treatments, the total fertilizer dose was split into 4 applications, the first at the beginning of the dry season and the remaining 3 in the early, mid, and late rainy season.

 

Treatment Urea Fused
Ca Mg P
KCl NPKS
16-16-8-13 
NPK
15-15-15
NPKS
15-18-20-10
Polysulphate 
kg/hakg/hakg/hakg/hakg/hakg/hakg/ha
Control 715 1,193 545 
Compound
fertilizers + S
250 200 400 500 500 
Compound
fertilizers + S
with Polysulphate
250 153 400 500 500 200 

Treatments

This completely randomized block trial comprised 3 replications, each with 3 treatments:

  1. Traditional practice/control: single application of urea, KCl, and fused Ca, Mg, and P.
  2. Commercially available compound fertilizers (with S but no Ca or Mg).
  3. Same as as the commercially available compound treatment (2. above) but supplemented with Polysulphate.

In the 2 treatments, the total fertilizer dose was split into 4 applications, the first at the beginning of the dry season and the remaining 3 in the early, mid, and late rainy season.

 

Treatment Urea Fused
Ca Mg P
KCl NPKS
16-16-8-13 
NPK
15-15-15
NPKS
15-18-20-10
Polysulphate 
kg/hakg/hakg/hakg/hakg/hakg/hakg/ha
Control 715 1,193 545 
Compound
fertilizers + S
250 200 400 500 500 
Compound
fertilizers + S
with Polysulphate
250 153 400 500 500 200 

Results

  • Supplementing NPK with Polysulphate resulted in an increase in yield of 11.5% and superior quality produce – more than 22% of the cores were of size A, or larger than 6.3 mm in diameter.
  • Higher yield was due to faster growth, longer fruiting branches, less shedding of immature fruit, and larger and heavier cores.
  • Polysulphate application also increased net profits by 14%.

 

Supplementing NPK with Polysulphate increased coffee yield by 11.5%

Supplementing NPK with Polysulphate increased coffee yield by 11.5%.

 

Polysulphate fertilizer increased coffee fruit weight

Polysulphate fertilizer increased coffee fruit weight.

 

Number of size A coffee cores increased by 22% with Polysulphate

Number of size A coffee cores increased by 22% with Polysulphate.

Bars indicate LSD at 5%.

 

Source: Petrovietnam Fertilizer and Chemicals Corporation

 

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