Growth of Tomato on a Tropical Soil under Plastic Cover as Influenced by Irrigation Practice and Soil Salinity1

Abstract

Abstract When soil-water tension in the rootzone was maintained below 0.2 bar the yield of marketable ‘Tropic’ tomato was 17% greater than when tension was maintained below 0.4 or 0.6 bar. At all 3 tensions yields and total amounts of irrigation water required under trickle irrigation did not differ significantly from yields and water required under basin irrigation. Soil salinity tended to increase with decreases in the total amount of irrigation water applied and with distance from the center of the row. These tendencies were slight under basin irrigation but marked with trickle irrigation. The salt tolerance of ‘Tropic’ appears to be lower than that reported for other cultivars; tolerance was considerably lower on highly acid soil (pH 4.1) than on limed soil (pH 5.7). With limed soil the electrical conductivities of the soil water at field capacity associated with yield decreases of 10, 25 and 50% were 3.5, 6.8 and 12.2 mmho/cm, respectively, as compared to corresponding U.S. Salinity Laboratory values of 8.0, 13.4 and 16.0 mmho/cm.