As part of the IntercropValues project, eRcane and CIRAD have presented to the French Overseas Agricultural Innovation and Transfer Network (RITA) a summary of the knowledge acquired on sugarcane intercropping systems, at the annual steering committee meeting. This committee brought together representatives from the sugarcane agricultural sector, including farmers. The summary was published in the technical journal Carocanne and distributed to all the island’s farmers. This knowledge will serve as a basis for co-designing associations within the network of growers in the sugarcane case study in the IntercropVALUES project (CICS#07).

Picture above: sugarcane and cover crop intercropping

The summary of ten years of trials (2012 to 2021) of cover crops shows an average reduction in weed cover of 46%. However, results vary considerably depending on the plants used and the invasive weed species.

Cover crops limit weed cover by occupying the interrows to the detriment of weeds. But they also compete with sugarcane, albeit to a lesser extent. 

Picture above: sugarcane and cover crop intercropping

Regarding yield, the eRcane trials recorded an average yield reduction of 6% with cover crops compared to the yields obtained with more conventional practice. Competition between cover crops and sugarcane, which impacts the number of stalks and their root volume, is greatest in the first six months of the sugarcane cycle. 

Cover crops, a source of nitrogen

Questions about competition between legume cover crops and sugarcane for mineral nutrition focused on nitrogen. No competition was observed for urea between legumes and sugarcane. Legume cover crops bring nitrogen to the soil through decomposition.

Picture above: sugarcane and cover crop intercropping

This is one of the expected services. However, in the presence of straw, this contribution is reduced by half or even three-quarters: the nitrogen released by the aerial part of the plant is captured by the straw and volatilized. To overcome this drawback, studies are currently underway to adapt the crop management.

This news item was written by the team of CIRAD and eRcane based in Reunion island (France).