Effects of cropping systems and irrigation on the bio-agronomic and quality response of industrial tomato (Lycopersicon esculentum mill.).

Abstract

This paper shows the results obtained in 2009 of a study carried out by the Dipartimento di Agronomia Ambientale e Territoriale (D.A.A.T.) aimed at identifying and evaluating various low input cropping systems for industrial tomato varieties, a traditional farming crop in Sicily. The tests were carried out on the Sparacia experimental farm (Cammarata AG, 37°37’N, 13°42’E). The farm is located in a sub-arid area with average rainfall levels of approx. 500 mm and average min/max temperatures of 9 and 21°C. The soils, typical of soil types in the area, are Eutric Vertisols. A split-split plot design with three repetitions was adopted and the following variables were studied: 1) management of crop residue from wheat (MR) in the main plots which has two levels: burning of crop residues (BR) and ploughing in of crop residues (P-in). 2) Land management (ML) (sub plots) with two levels: transplanting the tomato into fallow land (FAL) and into cover crop land (GM) after the cover crop has been ploughed in. 3) Irrigation (IRR) (sub-sub plot) with two levels: restoring 75% of evapotranspiration losses (V1) and 45% of evapotranspiration losses (V2). A drop irrigation system was used at the rate of 2.5 L•h-1 with an inter-dripper spacing of 33 cm and at two-day intervals. During the initial soil preparation for the tomato, the biomass of the cover crop (Trifolium alexandrinum ‘Lilibeo’) was ploughed in at a rate of 6.5 t•ha-1, providing an estimated 52 kg•ha-1 of N. The tomato cultivar used was the industrial hybrid Joy. Data analysis showed an improvement in the physical and chemical properties of the soil, as increases in the soil carbon content of all of the test treatments showed. The production levels and quality of the tomato were found to be highly dependent upon water availability. The most productive test scenario was that of the combination P-in x GM x V1 (83.8 t•ha-1). A reduction in the volume of water supplied to the crop resulted in a fall in quantity but an improvement in the quality of the tomato produced – as shown by a the Brix value which resulted higher in V2 combined with all the other study variables.