Improving Alfalfa Production with Polysulphate

Polysulphate is ideal for alfalfa production, supplying potassium and other nutrients to this important livestock forage crop.

2 mins

Research demonstrates the higher biomass yield achieved when using multi-nutrient Polysulphate fertilizer on alfalfa in Brazil to supply this important forage crop for livestock with potassium and other nutrients.


Wanting Better Fertilizer Response in Brazil

Brazil is the fourth largest fertilizer user in the world. A quarter of what is applied is potassium fertilizers, demand for which is driven by the fact that poor acidic soils hinder availability of potassium to crops. However, despite increasing use of potassium fertilizers, mainly potassium chloride, agronomic efficiency is poor. Farmers want better nutrition for their crops, especially alfalfa which is a pillar of Brazilian livestock production.


Comparing Sources of Potassium

An experiment to compare polyhalite with alternative sources of potassium was carried out at EMBRAPA’s southeastern regional research center. The experiment grew alfalfa in pots of local soil, with a range of different fertilizer treatments. Four different potassium doses with seven fertilizer combinations were applied.


Polysulphate – Much More than a Potassium Fertilizer

In the experiment, Polysulphate application, alone or in combination with potassium chloride, gave rise to significantly higher biomass yields than potassium chloride, with or without gypsum. Polysulphate significantly enhanced K, S, Ca, and Mg uptake, particularly when applied alone at the highest dose.

The next phase is large scale field experiments to confirm the findings, but for now an important step has been taken in understanding the role of Polysulphate in feeding the alfalfa crop in Brazil efficiently and effectively.

This summary is extracted from the full research paper “Polyhalite Compared to KCl and Gypsum in Alfalfa Fertilization” available from the International Potash Institute.



The paper Polyhalite Compared to KCl and Gypsum in Alfalfa Fertilization is published in e-ifc No. 52 by the International Potash Institute.