Biomass production and dry matter partitioning of processing tomato under organic vs conventional cropping systems in a Mediterranean environment

Modern agriculture should increase crop sustainability while feeding the growing population. The organic cropping system has emerged as an interesting alternative and more sustainable crop management than conventional one. Unfortunately, the current yield gap between organic and conventional systems is significant for most crops, and this limits the organic system's value. Hence, the objective of this study was to investigate biomass production and partitioning of processing tomato genotypes cultivated in organic vs conventional cropping systems in a processing tomato growing area in the Mediterranean. From 2010-2012, field trials were carried out in two farms in Southern Italy. At the end of the crop cycle and in average among years, processing tomato cultivated in organic cropping system showed reductions of: total biomass dry weight (-25%), leaf area (-36%) and radiation use efficiency (-24%). The biomass distribution to fruits and leaves was highly similar under both managements, while a higher fraction of total biomass was allocated to stems (+34%) and to roots (+41%) in the organic cropping system. In the studied environment, a major cause of different fruit dry weight and, consequently, of yield gap between organic and conventional cropping systems was the reduction of the source, ie. the lower leaf area, that led to a reduction of total biomass dry weight.