BLACK POLYETHYLENE MULCH DOUBLED YIELD OF FRESH-MARKET FIELD TOMATOES

Field experiments were conducted to a) maximize total yield of fresh-market field tomato (Lycopersicon esculentum Mill.) cultivars using black polyethylene mulch (BPM), and b) increase fruit size and yield during the last 5 weeks of the production period by reducing the number of synthate sinks per plant through eliminating all flowers that appeared during this period. Unmulched treatments under trickle irrigation and multiple applications of soluble fertilizer yielded an average of 43 t-ha-1 for 'Sunny' and 'Pik-Rite' over the two planting dates. With BPM, total yield increased by 95% to 84 t-ha-1. Although total yield increases due to BPM over the control were highly significant in both cultivars and over the two planting dates, yield increases were higher for the early than for the optimum planting date. BPM also significantly increased early production of 'Pik-Rite but not 'Sunny', and the increase in early production was more pronounced for the optimum than the early planting date. Sink reduction during the last 5 weeks of the growing season had no effect on yield or fruit weight during that period.