Global Maize Project in Argentina: Oro Verde, Entre Ríos

A long-term field experiment was established at Oro Verde, Entre Ríos, Argentina beginning in the 2009 growing season. The crop rotation used was maize-wheat/double cropped-soybean, with both crop phases occurring each year. Soil samples were collected during site establishment to characterize initial conditions, especially the carbon content in the entire soil profile. Treatments included current farmer practice (FP) and ecological intensification (EI) practices. Treatments differed in cultivars, planting dates, pest and weed control, or nutrient management practices.

Grain yields in the 2013-14 season showed significant differences between FP and EI treatments for wheat. Maize yields were greatly affect by drought and averaged 5.3 t/ha in both treatments. Wheat yields were 2.7 t/ha and 4.5 t/ha for FP and EI treatments, respectively. Double-cropped soybean yields averaged 3.7 t/ha for both treatments. Cropping intensification (i.e., inclusion of a cover crop before maize) significantly improved maize grain yield despite the drought (+13%).

Considering the five years of field experiments, the EI treatment has significantly improved maize and wheat yields (+45% and +13%, respectively) but it did not affect double-cropped soybean yields. Water use efficiency (determined as kg grain per mm of evapotranspiration or ET) improved under EI over FP, but the treatments did not differ much in the capture of water (ratio of ET/total precipitation). The EI treatment also had higher physiological N use efficiency and less negative N balances, but lower partial factor productivity of N when compared with the FP treatment.