NITROGEN FERTILIZATION OF EGGPLANT (SOLANUM MELONGENA L. VAR. ESCULENTUM) TRANSPLANTS AND THEIR IMPACT ON CROP GROWTH AFTER TRANSPLANTING

The aim of this study was to evaluate the influence of nitrogen fertilization on growth pattern of eggplant seedlings and on plant growth after transplanting. A greenhouse and open field trial was set up with different rates of N fertilization provided to transplants (N0 = 0, N1 = 150 and N2 = 300 mg L^-1) and two rates of N fertilization on plants established in the field after transplanting (-N = 0 and +N = 100 mg N L^-1) in the irrigation water. Partitioned and total fresh and dry weight as well as leaf area (LA) were measured 12, 24 and 53 days after emergence, and 21, 40 and 51 days after transplanting. Days to flowering were recorded. Partitioned and total dry matter, specific leaf area (SLA), leaf area ratio (LAR), leaf area duration (LAD), net assimilation rate (NAR), absolute and relative growth rates based on fresh and dry weight (AGRf, AGRd, RGRf, RGRd), and absolute and relative leaf expansion rates (ALER, RLER) were calculated. The application of 300 mg N L^-1 increased total fresh weight, LA, LAD, ALER, RLER and AGRf at transplanting as compared to the control. The 300 mg N L^-1 treatment also increased the total dry weight and AGRd significantly as compared to 0 and 150 mg N L^-1. Fertilization post-transplanting produced higher total fresh and dry weight, LAR, RLER, AGRf, AGRd, RGRf and RGRd as measured 51 days after transplanting. At that stage, no differences among nitrogen application rates during transplant production were found. Post-transplanting fertilization increased the LA and the SLA of the established plants, and no significant differences were found for the other parameters analyzed. The initial stages of eggplant growth in the field up to flowering were more affected by post-transplanting N fertilization than by N fertilization during transplant production.