Estimating water requirements of tomato plant based on Forecast-Evapotranspiration Equation in Semangat Village, Merdeka Sub-district, Karo Regency, North Sumatera Province, Indonesia

Abstract

Tomato plant is one of the horticulture products that produce in Semangat Village. One of the problems focused by tomato’s farmer was how much water will give. Estimating water requirements for tomato plants will make it easier for farmers to provide water according to the phase of plant growth. The aims of the research was to estimating water requirements of tomato plants in Semangat Village Merdeka District, Karo Residence. The methods divided two steps, they were analysis the forecast-potential evapotranspiration, and estimating water requirements of tomato plant where calculated by the relation of crop coefficient and forecast-potential evapotranspiration. The results showed forecast-potential evapotranspiration (ETo) in Semangat Village were 3.36 – 6.89 mm/day during January until July, 2020. The water requirements of tomato plant showed 3.141 mm/day in the early phase, 6.02 mm/day in the middle phase, and 4.188 mm/day in the final phase. The conclusion showed that the water requirement of tomato plants for all of growth phase was increase as high as crop coefficient of tomato plants.