Alongside our farm standard 33cm row spaced Soya, we decided to plant a trial field at 66cm row spacing with the intention to inter-row sow a continuous companion crop. However, the unforeseen dry weather meant that by late May, the ground was cracking extensively. With no rain forecasted in June, we took the decision not to plant the companion crop. The companion crop seeds were to be shallow sown and with the moisture in the top 2 inches of soil already lost it was deemed not viable.
We were left with an unusual looking Soya field, drilled on rows double the width of the rest of the farm. Both the farm crop at 33cm spacing and the trial crop at 66cm spacing were sown with the double shoot coulter at the same seed rate. Interestingly, as the season progressed the difference in crop height between the two became noticeable. By pod fill, the wide row trial field was up to 50% taller and generally bushier than the standard 33cm drilled crop. In line with other crops across the farm the wider rows allowed for more light interception throughout the crop and a larger reserve of untilled soil providing more moisture to the growing crop.
The wide row spacing using a double shoot coulter replicates a common method used in Australian dryland cotton production where the ‘skip row’ method is used. Literally skipping a row provides plants with a greater volume of untilled surrounding soil and thus, access to a greater supply of moisture. This is important for enabling the crop to better withstand a prolonged dry spell and help to mitigate some of the impact on yield in dry climate. Whilst we don’t have reliable continental weather patterns to help us plan our planting method each year, this has proven to be an interesting insight into the effect of 9 weeks of dry and hot weather on a Soya crop with different row spacings.