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) practice. Treatments differed in cultivars, planting dates, pest and weed control, or nutrient management practices.

Grain yields in the 2012-13 season did not show significant differences between FP and EI teatments for any of the three experimental crops. Maize yields were 7.4 and 9.6 t/ha, wheat yields were 2.2 t/ha and 2.5 t/ha, and double cropped-soybean yields were 2.9 t/ha and 3.0 t/ha in FP and EI treatments, respectively. Considering the first four years of the experiment, the EI treatment significantly improved maize yields but it did not affect wheat and 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. Satellite field experiments evaluating cropping intensification (i.e., increasing numbers of crops per year) have shown that this approach would be an alternative practice to increase C inputs and soil organic C. Also, the evaluation of late season N applications in maize (V10-14) have shown positive preliminary results in improving grain yields and N use efficiency.