ARS | Publication request: Sugarcane yield response to soybean double-cropping in Louisiana

Submitted to: Crop Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 21, 2011
Publication Date: July 21, 2011
Citation: White Jr, P.M., Viator, R.P., Richard Jr, E.P. 2011. Sugarcane yield response to soybean double-cropping in Louisiana. Online. Crop Management. doi:10.1094/CM-2011-0721-01-RS.

Interpretive Summary: Soybean (Glycine max) production during the fallow period between sugarcane crops offers several opportunities to sugarcane growers in Louisiana including additional cash crop, green manure crop for supplying additional nitrogen, and a cover crop to reduce erosion and control weeds. Interrupting the continuous planting of sugarcane with legumes has shown to reverse yield decline. Soil erosion, as well as weed control, may also benefit. The objective of the experiment was to determine if soybeans grown in the usual fallow period would afford sugarcane growers with an additional cash crop while not impacting the primary crop, sugarcane, through cane yield, theoretical recoverable sugar (TRS), and sugar yield. The experiment was conducted in two successive years (2004, 2005) with two varieties: ‘L 97-128’ and ‘HoCP 96-540.’ A starter fertilizer treatment was included to determine if any yield loss associated with soybeans could be offset with additional fertilizer inputs. Soybeans did not affect cane yield, TRS, or sugar yield, with mean values of 107 Mg ha-1, 108 g kg-1, and 11,700 kg ha-1, respectively. There was no sugarcane variety or starter fertilizer response in with regards to cane and sugar yields. Soybean yield averaged across both years was 2,400 kg ha-1, which at current commodity prices ($0.42 kg-1) make the crop worth $980 ha-1. Calculated total observed costs (inputs) for the soybean crop were $468 ha-1. Thus, a profit of $522 ha-1 was realized. The planting of soybean as a complementary crop during the typical spring/summer fallow period between the planting of sugarcane can serve as an additional source of revenue with no adverse impacts on the sugarcane crop.

Technical Abstract: The interruption of continuous sugarcane plantings with a soybean (Glycine max) crop during the spring/summer fallow period between sugarcane plantings represents an economical opportunity for sugarcane growers in Louisiana. The objective of the experiment was to determine if soybeans grown in the usual fallow period would affect the primary crop, sugarcane, through cane yield, theoretical recoverable sugar (TRS), and sugar yield. The experiment was conducted in two successive years (2004, 2005) with two varieties: ‘L 97-128’ and ‘HoCP 96-540.’ With and without starter fertilizer at the time of planting sugarcane was included to determine if any yield loss associated with soybeans could be mitigated with additional fertilizer inputs. Soybeans did not affect cane yield, TRS, or sugar yield, with mean values of 107 Mg ha-1, 108 g kg-1, and 11,700 kg ha-1, respectively. There was no variety or starter fertilizer response observed. Across years soybeans yielded 2,400 kg ha-1, which at current commodity prices ($0.42 kg-1) make the crop worth $980 ha-1. Calculated total observed costs for the soybean crop were $468 ha-1. Thus, a profit of $522 ha-1 was realized. Estimated soybean crop residue half-life was 75 days, or nearly one year ahead of plant-cane harvest. Overall, soybeans cropped between sugarcane plantings provide an economic incentive to growers and do not affect subsequent sugarcane yields.