Physiological responses to several organic compounds applied to primary leaves of cowpea (Vigna sinensis L.)

Laboratory bioassay of the effects of foliar nutrient applications on physiological and morphological responses (growth stimulation, dry matter production and partitioning) of model plants may help in the optimisation of foliar nutrition. The present study was carried out to compare five commercial and experimental organic products and to find their optimal concentrations, using Vigna sinensis L. seedlings under laboratory conditions. The products compared were: Zymo (experimental product containing humic acids), Cifoumic E.C (commercial product based on humic acids), Enersoil (commercial humic acids extract from leonardite), Torba Viva Express (commercial product made from fermented olive husk), Maxicrop (commercial product based on marine algae, Aschophyllum nodosum). When applied at low concentrations, the treatments increased total plant elongation and growth, and leaf and root dry matter allocation compared to a control but without significant differences among products.