Petiole sap N and K quick tests offer fast and accurate in-field analysis for N and K and have been calibrated for some vegetable crops in Florida. This paper summarizes 10 years of research conducted in Florida on petiole sap testing for N and K. Petiole sap nitrate-N and K concentrations correlated highly with whole-leaf N and K concentrations and decreased through the season for all vegetable crops tested. Optimum early season fresh sap nitrate-N and K concentrations were highest for pepper, and optimum late-season concentrations were lowest for tomato. Petiole sap nitrate-N and K concentrations were not affected by storing petioles on ice for up to 16 h or freezing them for 24 h.
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