Issue 4 2019
A bunch of good news on bananas

The lyrics in the song are “there’s an awful lot of coffee in Brazil”. Well, now there’s set to be an awful lot more bananas in Brazil and elsewhere in the world. That’s all thanks to exciting new evidence of the difference that Polysulphate as a source of potassium (K) has on yield and quality of this ever-popular fruit.

No need to hold back on growth

We love to find places and crops with productivity problems so that we can put Polysulphate through its paces. In Juquiá, in the state of São Paulo which is the highest banana-producing region of Brazil, production can hit a plateau. Is something – or perhaps some nutrient – holding growth, flowering and fruit growth back?

Feed the crop that feeds us

Bananas are a rich source of potassium in the human diet. Banana plants themselves are often known as ‘heavy feeders’. They require adequate nitrogen during the leaf growth stage but for vigorous development and flowering a high potassium fertilizer is what’s needed.

For global banana production to keep up with growing demand (the world ate over 114 million tonnes of bananas in 2017 according to FAO) then precise and balanced banana crop nutrition is what’s needed.

Polysulphate on trial

To evaluate the effect of substituting KCl fertilizer with Polysulphate as a source of K, we set up a trial in which we applied a range of treatments from pure KCl, various combinations of KCl and Polysulphate through to pure Polysulphate. The fertilizer treatments went on the soil twice and at the same time as the usual ammonium nitrate was applied. All that was left to do was to measure the diameter of the stems, the vigour of the bunches and what weight of bananas were produced.

Average weight (in kg) of each bunch obtained during harvest in the last week of August 2017; converted to t/ha of bananas; and vigor of bunches on June 9th 2017,  grades from 0 to 10 (low to high). Different letters above bars indicate significant differences among treatments (P<0.05).
Pick of the bunch

And the results? Polysulphate increased the vigour of bunches and slightly increased the diameter of the stems. But the top news is what happened at the top of the plant where the large cluster of bananas hangs, with up to 20 tiers of fruit. Yield peaked at almost 30 t/ha in the plots where the fertilizer blend was 60% Polysulphate and 40% KCl, a 12% increase in yield as compared to the 0 K2O treatment.

These findings, from this research funded by the International Potash Institute, are now being shared with banana farmers in this part of Brazil and elsewhere. With improved vigour, increased stem diameter and a serious yield increase that’s a whole bunch of good things to ‘go bananas’ about.

See the results in the ‘Experiments’ section of the Polysulphate website: 

Trial plot of banana in Lagoinha farm, Juquia, Sao Paulo state, Brazil.
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Mined in the UK, ICL is the first – and only - producer in the world to mine polyhalite, marketed as Polysulphate