Sulphate of Potash for WA Farmers (SOPWA)

An Australian first, two-year controlled environmental study and broadacre field trials, commenced in 2019, analysing the benefits of WA produced SOP (SOP) fertiliser.

The Australian Potash Limited, SOP for WA Farmers (SOPWA) project will compare commonly used MOP (MOP) with SOP and investigate the full effects of both potassium sources on crop yield, quality, safety and value.

Another first is the research collaboration between the Western Australian No-Tillage Farmers Association (WANTFA), The University of Western Australia's Institute of Agriculture, and APC. for the research programs. These trials will also investigate crop response to SOP and soil biology in comparison to MOP. Such comparative studies have not been done in the past.

Five trial sites, using farmers equipment, were established at Bolgart, Tammin, Southern Cross, Kojonup and Grass Patch during May and June to investigate crop safety and productivity of SOP compared to MOP. Trials varied in their design and size to suit the grower's interests and capacity with their seeding equipment. Treatment plots were sown as a strip over the entire length of paddock to wheat (typically between 400 and 1200 m in length) and replicated three times (one trial 20), so full statistical evaluations could occur. Potash treatments across all five sites included; top-dressed, drilled with the seed or banded below the seed.

Paddock Trial Sites

The aim is to determine the crop safety and productivity of SOP compared to MOP under field conditions using growers farm equipment.

Hypothesis 1: That SOP has more crop safety compared to MOP when applied with wheat seed.

Hypothesis 2: That SOP is at least as effective a source of potassium for crop growth and yield as MOP under Feld conditions using Growers farm equipment.

To compare the responses of canola and wheat to local SOP, which has the lowest salt index of any potassium fertiliser, and widely used MOP, which has a higher salt index but significant price advantage over imported SoP. Also, compare leachability and seeding safety of the fertilisers.