INTERACTION OF LATE-SEASON FOLIAR SPRAY OF UREA AND FUNGICIDE MIXTURE IN WHEAT PRODUCTION

Nitrogen (N) fertilization with foliar urea and fungicide treatment at flag leaf emergence (GS 47) are common strategies to improve both grain yield and quality in wheat (Triticum aestivum L.). Mixing of urea and a fungicide, together, would save time in farm operations. In some cases, the effect of foliar sprayings of urea either alone or in combination with a fungicide may, however, give unexpected low response to grain yield and quality when compared to separate application of foliar urea and fungicide. This study was designated to provide more detailed information about the effects of late-season spraying of urea (15 kg N ha-1 as an aqueous solution of 110 g l-1) alone or mixed with fungicide (propiconazole, 125 g ha-1) on the grain yield and grain protein content of spring wheat. To avoid foliar injury or phytotoxic effect of foliar spray of urea, mixing of urea with propiconazole in warm growing conditions should be avoided. In turn, during cool and rainy growing season, a mixture of these two chemicals is recommended in order to improve rapid absorbtion of both propiconazole and foliar urea. However, the genotypic differences were recorded in response to propiconazole and urea sprayings. The positive effects on cultivars of these chemicals were attributed to high leaf photosynthesis rate after propiconazole and foliar urea treatment and high leaf urease enzyme activity after foliar urea application.