The influence of non-living mulch, mechanical and thermal treatments on weed population and yield of rainfed fresh-market tomato (Solanum lycopersicum L.)

Weed control is often a major limitation for vegetable crops, since compared to arable crops fewer herbicides are available and the crops are more sensitive to weeds. Field experiments were carried out in the province of Pisa (Central Italy) to determine the effect of two different mulches (black biodegradable plastic film and wheat straw) and mechanical and thermal treatments on weed population and yield of rain-fed fresh market tomato (Solanum lycopersicum L.). Rolling harrow, flaming machine and precision hoe for weed control, which were either built, enhanced or modified by the University of Pisa were used separately (mechanical-thermal strategy) or in combination with a straw mulch (mechanical-thermal-straw strategy). These two innovative strategies were compared with the traditional farming system, which uses a biodegradable plastic mulch film. The strategies were compared in terms of machine performance, weed density, total labour requirement, weed dry biomass, and crop fresh yield at harvest. The total operative time for weed control was on average ~25 h ha–1 for the two systems, which included mulching, and over 30 h ha–1 for the mechanical-thermal strategy. The three strategies controlled weeds effectively, with only 30 g m–2 in each treatment. Tomato yield, however, was 35% higher for strategies that included mulching (both biodegradable film and straw).