First results of mechanical direct sowing of processing tomato on biodegradable mulch film

Processing tomato (Solanum lycopersicum L.) is among the most widely grown horticultural crops in the world. In recent decades, processing tomatoes have been benefiting from soil mulching, and for this reason the mulched area continues to increase worldwide. Notably, only 3.6% of currently used mulch films are biodegradable, while the rest are plastic materials, usually polyethylene, which raise critical disposal issues. The purpose of this work was to evaluate the mechanical direct sowing of processing tomato on biodegradable mulch film grown in an area highly suited for its production. The experimental work was conducted at Lesina in the province of Foggia, Italy. The site has a Mediterranean climate with mild winters and dry-and-warm summers. Cherry tomato, genotype Cesarino, was mechanically sown on biodegradable mulch film and compared with seedlings of the same genotype mechanically transplanted on biodegradable mulch film. Throughout the crop cycle (emergence, flowering, fruit set, fruit ripening and harvest), weather parameters were monitored and agronomic (plant height, soil water content, collar diameter, and aboveground and belowground biomasses), physiological (phenological phase (BBCH), leaf pigments such as chlorophyll and leaf temperature) and fruit qualitative (pH and °Brix) traits were recorded. Considering spatial and temporal variability three field replications (20×1.7 m) for each treatment were used. All collected data were subjected to analysis of variance (ANOVA), and means were separated by Duncan's test at p<0.05. The experiment reported interesting results, in fact, the technique of the direct sowing on biodegradable mulch film reduced the volume of the irrigation water (-48%) and the nitrogen use (-23%), while preserving fruit yields and quality. These results were putatively due to the higher root length and growth of plants resulting from direct sowing than transplanted seedlings.