The effect of fertilization regime on growth parameters of Sonchus oleraceus and two genotypes of Portulaca oleracea

Wild edible plants of the Mediterranean represent an extraordinary food source and are basic ingredients in the “Mediterranean diet”. However, there is a scarcity of information about their commercial interest or cultivation practices. This study was conducted to evaluate how different amounts of inorganic and organic fertilization affected plant growth parameters of Sonchus oleraceus and Portulaca oleracea. The experiment was performed in greenhouse conditions, in pots containing soil, sand and vermiculite in the volume ratios of 1-1-1 during 12 weeks. The control treatment had no fertilization; inorganic fertilization (N-P-K) were 100 mL of 100-100-100 mg L^-1; 300-100-100 mg L^-1; 600-100-100 mg L^-1; 300-200-100 mg L^-1; 300-300-100 mg L^-1; 300-200-200 mg L^-1; 300-200-300 mg L^-1; and 100 mL of organic compost extract to reach same equivalence than 300 mg L^-1 of N) and 100 mL of organic compost extract + P inorg (equivalent to 300 mg L^-1 of N and 200 mg L^-1 of P). All treatments were applied weekly. All treatments assayed showed significantly higher leaf and stem weight compared to the control treatment, being the highest values recorded for the treatment of 600-100-100 in both plant species (S. oleraceus and P. oleracea). Treatment (600-100-100) showed significantly higher N content than the rest of treatments, but not P and K. The plant nutrients content of Mg, Fe, S and Ca did not differ among the tested fertilization regimes. Soil nutrients content (N, P, K, Fe, Ca) showed no differences between treatments. We conclude that nitrogen had a main role improving plants growth parameters and yield in both wild plant species being the beneficial effect depending on the fertilizer doses and origin (inorganic or organic) applied.