Irrigation, Mulches, and Fumigants on Tomato Performance in Sandy Soils

Current best management practice programs in Florida aim to reduce water volumes needed for producing vegetable crops. Therefore, irrigation practices that save water while maintaining the economic sustainability of those crops are desirable. Field studies were conducted to determine the effects of water management regimes on tomato (Solanum lycopersicum L.) production and assess the effects of highly retentive mulches and methyl bromide alternatives on water volumes necessary for tomato irrigation. Twelve treatments resulted from combinations of fumigant, mulches, and irrigation programs. The combinations of fumigants and mulches were as follows: a) methyl bromide + chloropicrin (67:33 v/v) at a rate of 196 kg·ha⁻¹ under metalized mulch; b) 1,3-dichloropropene + chloropicrin (65:35 v/v) at 150 L·ha⁻¹ under metalized mulch; and c) 1,3-dichloropropene + chloropicrin (65:35 v/v) at 300 L·ha⁻¹ under high-density polyethylene mulch. Irrigation methods were seepage (subsurface) irrigation alone at 5000 and 10,000 m³/ha per season and the same seepage irrigation volumes combined with a drip irrigation volume of 3500 m³/ha per season. Increasing seepage volume from 5000 and 10,000 m³/ha in combination with drip irrigation did not increase average soil moisture, which ranged from 9.0% to 10.3%. Irrigation volumes affected soil moisture when only seepage irrigation was provided, with values increasing from 9.4% to 11.9% when water volumes increased from 5000 to 10,000 m³/ha, respectively. Only irrigation affected total marketable fruit weight. Adding drip irrigation to seepage-treated plots positively affected fruit weight, increasing yields from 36.5 Mg·ha⁻¹ in plots with only seepage to 39.5 Mg·ha⁻¹. Increasing seepage irrigation from 5000 to 10,000 m³/ha in plots under drip irrigation improved yield from 34.5 to 44.5 Mg·ha⁻¹. However, increasing seepage volumes in plots without drip irrigation did not affect tomato total marketable yields.