Pumpkin response to microirrigation in two agro-ecological regions in Puerto Rico

Abstract

Pumpkin [Cucurbita moschata (Duchesne) Poir], one of the most important vegetable crops in the Caribbean, ranking second among all the vegetables produced in Puerto Rico, had a farm value of 4.1 million dollars for the 2009-2010 growing season. Drip irrigation is the method most commonly used to meet water requirements in many of the vegetables planted in Puerto Rico. However, more information is needed on water requirements and response to different applications. An experiment was established using Pan A evaporation readings to determine the appropriate microirrigation management practices to enhance pumpkin production. Pumpkin plants were treated with four microirrigation applications, consisting of four levels of evapotranspiration replenishment (ERT) treatments. The ERT levels used were 25, 50, 75 and 100%; levels were based on evaporation data recorded at two locations in southwestern Puerto Rico (Lajas and Juana Díaz). The Pan A evaporation method was utilized to estimate reference evapotranspiration (ET₀) and pumpkin evapotranspiration (ET_C). The ERT did not significantly and consistently affect total leaf area, biomass or yield at both locations, although occasionally significant interactions were found between ERT and leaf areas and biomass measured through time. On the basis of a two-year average, commercial yield in Juana Díaz tended to be higher than yield in Lajas by 1,594 kg/ha. Juana Díaz showed higher water use efficiency than Lajas. The ET_C estimates were found to be lower in Lajas.