Optimizing Plant Density in Processing Tomatoes under Drip Irrigation

Transplants are a relevant item in processing tomatoes cash costs. Growers usually keep the number of plants formerly used in furrow irrigation on crops irrigated by drip. The objective of this study is to check the impact of number of plant variation inside a single plant line keeping the same bed distance on fruit production on a drip irrigated crop using a compact and vigorous-vine variety. Trials were carried out in La Consulta Experiment Station in Mendoza, Argentina on typical torrifluvent soils. Each trial was distributed in a single plant and drip line 1,5 m apart and emitter tapes separated 0,3 m in the line. Water replacement was made according to evapotranspiration tank adjusted by Kc and fertilization was made by poultry manure 10 t. ha(-1) supplemented by 100 U of N and 50 U of P similarly in all treatments. Two varieties were included in this study: one compacted-vine XP 2510198, Monsanto and another vigorous-vine PS 2420487, Monsanto. Treatments were 10, 15, 20, 25 and 30 thousands plants ha(-1). Total, marketable, greens, sunburns, culls, blossom end rot index, fruit size and solids were evaluated by regression test under complete randomized blocks with five replicates. The results indicated that marketable and total yields were not affected by plant density. Optimal number of plants can be reduced in drip irrigation to 17000-19000 plants ha(-1). Fruit size is only reduced 10% by increasing from 15000 to 30000 plants ha(-1). Number of fruits and trusses per plant were dramatically reduced by increasing plant density. Compacted variety was easier to concentrate maturation than vigorous vine type and might be more susceptible to blossom end rot fruits than vigorous vine type under high plant densities.