Non-Chemical Weed Control on Open-Field Fresh Market Tomato in the Serchio Valley (Central Italy)

Fresh-market tomato is one of the most widespread Italian open-field vegetable cultivation, involving over than 23000 ha. A three year on-farm experimental trial (2006-2008) was carried out by the MAMA Division of DAGA Department and CIRAA “Enrico Avanzi” research centre of the University of Pisa in cooperation with San Giuliano Terme and Vecchiano municipalities (Serchio Valley, Pisa, Central Italy). The experiment was run in two different “pilot” integrated farms (the first one in 2006 and 2008 and the second one in 2007) placed in the Serchio Valley. Tomato was transplanted following a single row space arrangement. Crop density was about 10000 plants ha-1 (1,5 m x 0,7 m). Crop was not irrigated. The aim of the research was to compare three different non-chemical weed control methods: 1) biodegradable black plastic mulching film; 2) physical weed control on bare soil; 3) physical weed control plus straw dead mulch (only during 2007 and 2008). Biodegradable plastic mulch was placed just before crop transplanting. In this case just few hand weeding interventions were performed in addiction. No false or stale seedbed technique was carried out. This is the developing ordinary cultivation technique adopted in the area. Physical wed control on bare soil was performed with innovative operative machines built by the University of Pisa. Stale-seedbed technique was covered at by means of the rolling harrow (a patent of the University of Pisa) and an open flame operative machine before crop transplanting. Hoeing interventions were carried out with a precision hoe and the hoe conformed rolling harrow, both of them equipped with a hand guidance system and elastic tines for selective in-row weed control. In-row hand weeding was also performed when necessary. The third method consisted in the use of straw dead mulch together with the physical weed control strategy previously described. The straw mulch was placed just after the last hoeing intervention in 2007 and after crop transplanting in 2008. The purpose of the straw mulch use was to increase weed control effectiveness and water supply for the crop. Weed density, weed dry biomass at harvest, fruit fresh yield, operative machine performances and economic parameters were assessed. During the first year of experiment, the use of plastic biodegradable mulch allowed to reach high yields and lower weed dry biomass values at harvest with respect to the physical weed control method applied to bare soil. In 2007 the use of the straw mulch allowed to reach similar yield and economical parameters with respect to the biodegradable plastic mulch utilization, while physical weed control methods applied to bare soil gave again worse results. In 2008 the two innovative techniques allowed to reach higher yield and weed control levels with respect to biodegradable plastic film application.