Quick nitrogen tests for use on bean and sweet corn crops in Quebec (Canada)

Experiments and a survey were conducted to assess the potential of quick te sts for evaluation of N status of bean and sweet corn crops grown for proce ssing in Quebec (Canada). Merckoquant test strips and the Nitracheck reflec tometer were used for NO3-N quantification. Nitrogen fertilization was appl ied at 5 rates. N-min contents at sowing were relatively low both in commer cial fields or experimental plots. NO3 thresholds in sap at 3 weeks after s owing could be used as a way to quantify topdressing N applications but thi s NO3 content can vary from year to year. Chlorophyll-meter readings were n ot correlated to N application at a crop development stage early enough to adjust side dressed N applications. Bean was shown to leave a higher N-min, after harvest than sweet corn and may produce a higher N loss to the envir onment.