Nitrogen and Phosphorus Preconditioning of Small-plug Seedlings Influence Processing Tomato Productivity

Abstract

Seedlings of processing tomato `H 2653' (Lycopersicon esculentum Mill.) were cultured in 288-cell (< 6 cm 3 volume) plug trays in a soilless growing medium. Pretransplant fertilization with nutrient solutions containing 10 or 20 m m N and 2 or 5 m m P for 10 days altered the total ammoniacal-N and P, and the soluble NO 3 -N and PO 4 -P concentrations in the shoot tissue at transplanting. Post-transplanting shoot and root growth were more rapid in late May plantings than in earlier plantings. The 20-m m N and 2-m m P pretransplant treatment caused the most rapid shoot growth following early season plantings in the field. Rapid seedling establishment after transplanting was generally not a good indicator of potential fruit yield. The 5-m m P pretransplant treatment produced higher marketable fruit yields in early plantings but not in later. Culture of seedlings under a low fertilization regime (5.4 m m N, 1.0 m m P, and 1.6 m m K) before pretransplant treatment produced as high or higher fruit yields than did seedlings from a higher regimen. Withholding fertilizer temporarily before transplanting resulted in a depletion in tissue N and P concentrations, slow post-transplanting shoot growth, and lower yields.