Global Maize Project in Argentina: Balcarce, Buenos Aires

A long-term field experiment was established at Balcarce, Buenos Aires, Argentina in the 2009-10 growing season. The crop rotation 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. Maize crop in the 2012/13 season grew under some periods of dry climatic conditions, which affected the expression of improved potential yields in the EI treatments.

Maize yields were 7.6 t/ha and 8.3 t/ha in FP and EI treatments, respectively - a significant difference of 10%. Wheat grew under normal conditions for the region, and yields were 2.95 t/ha in FP and 4.0 t/ha in EI treatments - again a significant difference of +37%. Double-cropped soybean was planted immediately after the wheat harvest in early January, but the crop was lost because of early frosts during March. Considering the first four years of maize, the EI treatment significantly improved water use efficiency (determined as kg grain per mm of ET) over FP. The EI treatment also showed higher N use efficiency and N removal and less negative N balances, but lower partial factor productivity of N compared to the FP treatment for maize crop. Determinations of nitrous oxide (N₂O-N) gas emissions were conducted in the 2012-13 maize crop, and the data obtained is currently being analyzed. Satellite field experiments evaluating hairy vetch as cover crop for maize showed a significant N supply from the winter legume to the summer crop without negative effects on yield, even in four years years of contrasting climatic conditions.