An experiment on organic greenhouse vegetable production was carried out in Apulia (Southern Italy). The aim of this research was to study tomato under three organic production systems with different soil fertility management practices, by comparing their yields and environmental impacts. Production systems under comparison were: SUBST, which ‘mimics’ conventional production: bare soil and 100% off-farm organic fertilizers; AGROMAN, based on animal manure incorporation and cover crops cultivation to be flattened as dead mulch; AGROCOM, based on green compost and cover crops for green manuring. The experimental design used was a complete randomized block with triplicates. Yield, water consumption and nutrients (N,P,K) input and uptake were measured to evaluate the three systems performances, while nitrate concentration below root zone was measured to evaluate potential leaching.
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Organic carbon input and soil total organic carbon (TOC) were also assessed. Both tomato yield and nitrate concentration in all systems showed no significant differences. SUBST showed a balanced nutrients budget indicating a short-term fertility approach, while AGROMAN and AGROCOM resulted in N and K surplus balance contributing to long-term fertility. Since the beginning of the experiment (18 months ago), AGROMAN has significantly increased OC with respect to SUBST.
