With January nearly over attention will soon turn to potato planting, writes Yara’s Mark Tucker.

One area that gets discussed every year is that of the requirement for sulphur by this crop. There is always much debate on whether it is required for yield and/or quality. Both areas have had relatively limited attention in terms of trials.

The quality aspect is related to common scab control from the sulphur reducing pH. This has been trialled in the past with no conclusive evidence to prove that is works.

Last year an independent organisation carried out a trial comparing a number of fertiliser products that contained varying levels of sulphur with the highest applied amount being 354kg SO₃/ ha.

The variety was a main crop of Maris Piper with assessments for yield and skin quality being made at harvest. The results have again confirmed what Yara has reported before with no quality improvements being seen in the sulphur treatments.

The cleanest skins were seen from the Yara Complex (12.11.18 + 20% SO₃). This is an extremely high quality sulphate of potash-based product well suited for the potato crop and is a core part of Yara’s potato nutrition program.

The poorest skin quality came from the ammonium sulphate programme that had 354kg SO₃/ha applied. In terms of total yield again there was nothing to support high levels of sulphur, however with regards to marketable yield the trend indicated that a benefit does come from having between 75 and 140 kg SO₃/ha.

Again the highest yield (65-85 mm grade) came from the Yara Complex treatment. Further work is required to build on this first year study.