Effects of innovative biofertilizers on yield of processing tomato cultivated in organic cropping systems in northern Italy

Nowadays agriculture needs to increase crop sustainability and the organic cropping system has emerged as an interesting alternative approach with respect to the conventional one. On the other hand, the current unfavorable yield gap between organic and conventional systems reduces the organic system’s value. Processing tomato is a globally important horticultural crop and used as crop model. The objective of this study was to investigate different biofertilizers that could improve the yield and quality of processing tomato in organic cropping system. An experiment was conducted in Po Valley, northern Italy, during spring-summer 2017. The cultivar used was ‘Barone Rosso’ blocky fruit genotype, using 2.8 plants m-2, in randomized complete block design with seven biofertilizer treatments (pelleted digestate, granular biofertilizer, biochar, compost tea as foliar spray biostimulant, SiO2 as foliar spray biostimulant, compost tea + SiO2 as foliar spray biostimulant, zero biofertilizer as a control) and three replications. Agronomical and physiological parameters were recorded during the crop cycle. Results showed that tomato grown with biochar recorded the maximum commercial yield (136 t ha-1), followed by pelleted digestate (117 t ha-1) and compost tea + SiO2 as foliar spray biostimulant (113 t ha-1) while the minimum production (71 t ha-1) was recorded in untreated plots. On average, the results revealed that biochar, pelleted digestate and compost tea + SiO2 as foliar spray biostimulant, increased the vegetative vigor of plant (+10%), the number of flowers (+13%) and fruits (+41%), the average weight of fruits (+20%), the total biomass production (+48%), the harvest index (+15%) and the Brix t ha-1 (+49%), with respect to the control. Considering the overall performance, innovative biofertilizers could be promising to improve yield and quality of processing tomato cultivated in organic cropping systems, reducing the yield gap with conventional one.