Issue 6 2020
 
Soybean in Brazil: small changes make big differences
When there’s a lot to do, sometimes the finest of details can get overlooked. Take soybean growing in Brazil. Recent research has shown that, especially on the large-scale soybean fields, investing some attention to fine-tuning the fertilizer strategy for the crop with Polysulphate products can give a real boost to yields.

More from less

Brazil’s phenomenal productivity of soybean is well recognized. Production has reached in excess of 120 million tonnes a year or about 3.3 t/ha. However, there is a limit to how much land can be dedicated to the crop. Farmers would like to maintain yields and – better still – even increase them. So where could the yield come from? More balanced fertilizer strategy, particularly with regard to sulphur and potassium.
 
Overview of soybean experiment site at Rio Verde Foundation, Brazil.
Seek to find

A research team at the Rio Verde Research and Technological Development Foundation designed an experiment in collaboration with the International Potash Institute (IPI). The aim was to investigate the benefits of applying adequate potash and sulphur – using PotashpluS (a granular fertilizer made of Polysulphate and KCl) – compared with alternative and commonly-used sulphur fertilizers used on soybean in Brazil.

The experiment took place in the Cerrado region, at Rio Verde Foundation in the city of Lucas do Rio Verde, Mato Grosso state. The soil was a Red-Yellow Latosol, moderately acidic with low natural fertility. The experiment included six fertilizer treatments in a completely randomized block design with four replications. The rates of N, P2O5 and K2O applied in all treatments were 17, 80 and 80 kg ha–1,  respectively, while the S rate was 20 kg ha–1,  adjusted according to the blends of the fertilizers used in the experiment.

So, what did they find?

Of the different treatments tested, both monoammonium phosphate (MAP)+PotashpluS®, and MAP+single superphosphate (SSP)+KCl - both comprising sulphate as their sole S source - showed greater response potential. Both gave rise to significantly higher yields (10%) compared with common fertilizers where the partial or total S supply was in the elemental form. PotashpluS® broadcast pre-planting was as efficient as the SSP applied in the planting furrow. And there’s more.
 
Effects of fertilizer treatments on soybean grain yield at Rio Verde Foundation, 2019. Means followed by the same letters do not differ from each other.
Making best use of time

Practically, there were further benefits to large scale farmers of using PotashpluS. The soybean-sowing window is small. That leaves the farmers of the Brazilian Cerrado racing to get the crop in between mid-October and mid-November. PotashpluS is faster to apply and therefore increases the proportion of the crop sown in the ideal time which leads to better crop performance. 

PotashpluS® has been introduced recently and is available to soybean farmers in Brazil. It is a granular fertilizer formulated using a combination of Polysulphate and potash (MOP or KCl). While primarily a potash and sulphate fertilizer, it also contains essential Mg and Ca, and supplies all K and S crop requirements in a single application. The formula is 37% K2O, 9% S (24% SO3), 3% MgO and 8% CaO. Encapsulated in the same granule, nutrient segregation is avoided, even when fertilizer is broadcast at pre-planting. Sulphur, Mg and Ca are all in sulphate (SO4) form, ensuring high availability to plants. PotashpluS® ensures progressive supply of sulphur during the whole crop cycle due to the prolonged solubility pattern of Polysulphate which reduces the risk of sulphur leaching.

There is, as you’d expect, much more to this story. So, if you need to know more, take a look at the full report.
 
Visual appearance of the soybean experiment at phenological stages V3 (A) and R9 (B). While no differences between treatments occurred at V3 stage, slight but significant differences in FPP (final plant population) were recorded at R9 stage.
 
Mined in the UK, ICL is the first – and only - producer in the world to mine polyhalite, marketed as Polysulphate