Intensification of Crop Productivity: Yield, Nitrogen Use Efficiency, and Water Use Efficiency.

Grain yield must be increased to meet increasing food demand. The challenge for higher yields of production systems requires greater productivity of nitrogen (N), water and land, with the least possible impact on the environment. The development and implementation of tested practices of crop management are essential to ensure the necessary sustainable increases of productivity for the next decades. The objective of this work was to study the effect of an intensified technological package, which combines the best crop management practices, on yield, water use efficiency (WUE) and nitrogen use efficiency (NUE). Four years of a rainfed maize-wheat/soybean sequence under no-till system were evaluated in a long-term experiment started in 2009 at Balcarce (37°45’S, 58°18’W). The experiment combines, with a holistic approach, various management practices that had been shown to have positive individual effects on crop productivity and on resource-input use efficiency. This knowledge intensive management package could contribute to a sustainable crop production. Thus, two crop management systems were compared: i) control management (C), and ii) sustainably intensified management (IS), which includes the use of cultivars with high yield potential and yield stability higher rates of N, P and S application with the best management fertilization practices, higher plant density, narrow rows in maize, fungicides in wheat, etc,. Yield, WUE, NUE and their respective components were determined. Intensification resulted in higher yield and more efficient resources and inputs use. N uptake and NUE were higher for IS than for C. Physiological N efficiency was not reduced with IS management despite the increase in N availability and N uptake. Intensified management increased WUE and did not affect water consumption. This type of experimental approach integrates the many interactions among management practices that arise at a production system. To prove that this intensified package is sustainable, we are currently evaluating green-house gases emissions, leaching of agrochemicals, soil physical and chemical properties, profitability, etc.