ANAEROBICALLY MINERALIZED NITROGEN WITHIN MACROAGGREGATES AS INDICATOR OF WHEAT NITROGEN NUTRITION

ABSTRACT This work aimed to evaluate the capacity of anaerobically mineralized nitrogen (AN) within large (ANLM), small (ANSM), and total macroaggregates (ANTM) to predict grain yield, aboveground biomass, and total nitrogen (N) content of wheat (Triticum aestivum L.) plants as compared to AN in bulk soil (ANBS). Eight fields with non-N-fertilized wheat on Mollisols of the southeastern Argentinean Pampas were studied. Soil ANBS, ANLM, ANSM, and ANTM, and wheat grain yield, aboveground biomass, and plant total N content were determined. The ANLM, ANSM, and ANTM were positively related to grain yield, aboveground biomass, and plant total N content (R2=0.34-0.65). The relationships between ANBS and all those crop variables showed similar predictive capacity. Therefore, AN within macroaggregates was not a better indicator of soil nitrogen supply capacity than ANBS.