EFFECTS OF BIOFERTILIZERS ON GAS EXCHANGE, YIELD AND QUALITY OF SOME BROCCOLI CULTIVARS IN ORGANIC FARMING

Results of a field research to study the effects of biofertilizers applied by ferti-gation on gas exchange, yield and quality parameters of broccoli are reported. The trial has been carried out in winter period in Valenzano (BA, Southern Italy) on a sandy clay-loam soil. Three levels of organic fertilization (0, 60 and 120 kg ha^-1 of NewFert based on fleshing hydrolyzed, on 4 cultivar of broccoli (‘Marathon’, ‘Lord’, ‘Chevalier’, ‘Iron’), were compared. For the ‘Marathon’ was compared also seedlings grown conventionally with seedlings organically grown (‘Marathon’ org.). Gas exchange (net assimilation – A, transpiration – T, stomatal conductance – gs), water use efficiency (WUE), yield and quality were detected.
The different fertilizer treatments have not affected significantly yield and quality with the exception of the diameter of the inflorescence which increased with the increase of the dose of biofertilizer and ascorbic acid content that, instead, was reduced. The cultivars showed good qualitative characteristics especially nitrate con-tent that did not exceed 350 mg kg^-1 f.w. The most productive cultivar was ‘Chevalier’ (11.8 t ha^-1). Nitrate content was low, particularly in ‘Lord’ and ‘Marathon’ (160.9 mg kg^-1 f.w.), while a high level of ascorbic acid was recorded for ‘Chevalier’ and ‘Iron’ (71.9 mg 100 g^-1 f.w.). ‘Chevalier’ and ‘Iron’ presented the best characteristics for what concern colour, more green and shiny. The type of seedlings did not result in significant effects on gas exchange, yield and quality.