FIELD FERTILITY RESEARCH WITH P AND K FOR VEGETABLES - INTERPRETATIONS AND RECOMMENDATIONS

Research with eight major vegetable crops on phosphorus (P) and potass ium (K) requirements and Mehlich-1 soil-test calibration has led to ch anges in fertilization recommendations. Lack of crop response to P and K fertilization on soils testing high or very high did not support pa st recommendations of P and K fertilization for crops planted on such soils. Revised recommendations should call for no P or K applications to soils that test high in P or K. Research results from experiments i nvolving rates of P or K applied to soils testing less than high in P or K also did not substantiate the need for a different (higher) soil- test calibration for vegetables compared to agronomic crops. The calib ration for Mehlich-1 soil-test results for vegetables (revised) and ag ronomic crops are currently the same.