EVALUATION OF SOIL AND PETIOLE SAP NITRATE QUICK TESTS FOR BROCCOLI IN QUÉBEC.

This study was conducted to evaluate the potential of a quick test method, using commercially available nitrate test strips and a hand-held reflectometer, to assess the N status of petiole sap and soil in commercial broccoli fields. Experiments were conducted at two locations during the 1996 and 1997 growing seasons with factorial combinations of three and four N rates at planting and five weeks after planting, respectively. The use of quick nitrate tests on soil samples at planting was appropriate for adjusting initial N applications according to levels actually present in the soil. Petiole sap quick test results were related to N fertilization rates for both application dates. Also, quick N test data for sap samples were related to yield and head susceptibility to hollow stem, and have shown potential to quantify appropriate side-dressed N applications.