Investigate skip row configuration in sugar cane: Final report GGP046

Abstract

The aim of the project was to compare a double skip row sugarcane system with conventional solid plant on 1.8 m row spacing. Comparisons were made of productivity, profitability and water relationships. The skip row area was designated to grow crops which are usually cultivated over a traditional sugarcane fallow period. Ideally these skip area crops would provide break-crop soil health advantages but would also be harvested to contribute to income. One objective of this project was to evaluate different break crop alternatives to see which may be more suited to this situation. Results from this project show that the double skip row cane averaged about 70 % of the conventional cane yield, sugar yield and dollars returned per hectare. This excludes the data from the exceptionally wet 2010/11 summer which was in the wettest 5% of all years. Above-average rainfall years during the course of this trial negatively impacted on sugarcane and skip area crops. Only two skip row area crops were sown and that was to peanuts in August 2009 and November 2011. Again wet weather prevented harvest of these crops. The profitability of the double skip row system is under-estimated because costs were incurred to establish and manage the peanuts but no income was received. The group had hoped to evaluate soybean, sugar beet and possibly corn, but unfavourable seasons prevented this from happening.

Soil moisture comparisons between solid plant and skip were made using an Enviroscan. Particularly wet seasons complicated matters; for example, by producing a shallow water table at times during the summer. It was evident that the skip cane had a greater soil water resource to exploit. With regard to the skip’s effect on runoff water quality, the site flooded several times each year which made it impossible to calculate total runoff, sediment, nutrient and herbicide load during the season. There was no clear and consistent evidence that the skip was any worse or better than the solid row configuration in terms of runoff water quality. However given that cane occupied approximately 50% of the area, it is logical to expect a major reduction in potential nutrient/herbicide losses (depending on skip crop inputs).

Significant harvesting savings are possible with the skip, as time required to harvest the crop was lower (at least 30% less) than the conventional row configuration. Farmers have commented that the skip may have a role in short rows which occur towards the corners of irregular-shaped blocks. The grower group recommends that this trial be continued into the next crop cycle to determine the skip area effect on cane production. The next cane crop will be planted into the old skip areas. A profile of soil biology in the skip versus cane areas will be determined before the next crop cycle. Currently, double skip row cane is not a commercially viable option for farmers.