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 fertigation\non gas exchange, yield and quality parameters of broccoli are reported. The\ntrial has been carried out in winter period in Valenzano (BA, Southern Italy) on a\nsandy clay-loam soil. Three levels of organic fertilization (0, 60 and 120 kg ha-1 of\nNewFert based on fleshing hydrolyzed, on 4 cultivar of broccoli (‘Marathon’, ‘Lord’,\n‘Chevalier’, ‘Iron’), were compared. For the ‘Marathon’ was compared also seedlings\ngrown conventionally with seedlings organically grown (‘Marathon’ org.). Gas\nexchange (net assimilation – A, transpiration – T, stomatal conductance – gs), water\nuse efficiency (WUE), yield and quality were detected.\nThe different fertilizer treatments have not affected significantly yield and\nquality with the exception of the diameter of the inflorescence which increased with\nthe increase of the dose of biofertilizer and ascorbic acid content that, instead, was\nreduced. The cultivars showed good qualitative characteristics especially nitrate content\nthat did not exceed 350 mg kg-1 f.w. The most productive cultivar was ‘Chevalier’\n(11.8 t ha-1). Nitrate content was low, particularly in ‘Lord’ and ‘Marathon’ (160.9 mg\nkg-1 f.w.), while a high level of ascorbic acid was recorded for ‘Chevalier’ and ‘Iron’\n(71.9 mg 100 g-1 f.w.). ‘Chevalier’ and ‘Iron’ presented the best characteristics for\nwhat concern colour, more green and shiny. The type of seedlings did not result in\nsignificant effects on gas exchange, yield and quality.