The effect of substrates with compost and nitrogenous fertilization on photosynthesis, precocity and pepper (Capsicum annuum) yield

Fast-growing seedlings have larger immediate nutrient demands as compared with adult plants. A tray experiment was conducted to evaluate the fertilization of sweet pepper transplants growing on different substrates [Control (60% Sphagnum peat + 40% perlite), Mix I (45% Sphagnum peat + 30% perlite + 25% farmyard compost), Mix II (30% Sphagnum peat + 20% perlite + 50% farmyard compost), and Commercial (40% compost + Sphagnum peat + perlite + vermiculite)l with weekly applications of nitrogen N at rates of 150 and 300 mg.L-1, compared to a control without fertilization. Seedlings were transplanted in a randomized, complete block design with four replications. Leaf area and fresh and dry weights of leaves, stems and roots were measured for the transplants; the leaf weight ratio. specific leaf area, absolute and relative growth rates, leaf expansion rates, leaf area duration, and net assimilation rate were calculated. Precocity, early yield, and total yield were measured for the field crop. The application of nitrogen had positive effects on most growth parameters of seedlings growing on substrates with compost, promoting increased precocity and yield in the transplanted crop. Few benefits from nitrogen fertilization were observed for seedlings growing on substrates without compost. The main effect of the latter is to improve the efficiency of capture of the applied nitrogen, due to better water retention and ion-exchange capacity.