Determining Tomato’s Growth Response to air Temperature, Relative Humidity and Vapor Pressure Deficit in Tropical Lowland Conditions

Abstract. Peer-reviewed published literatures define tomato’s growth response (GR) as individual functions of air-temperature and relative humidity (RH) at different growth stages (GS) and light conditions (sun, night, cloud). These functions were implemented in an adaptive analysis framework to evaluate climatic parameter for optimum crop growth environment. Raw data, including air temperature, RH, wind speed and light conditions, were collected for a total of 126 days (from July to December 2013) in tropical lowlands (TL) of Malaysia. GR values (0≤GR≤1) were calculated and analyzed for each data set. Preliminary results indicated that averaged GR, corresponding to temperature, RH and vapor pressure deficit (VPD) were 0.71, 0.69 and 0.75 respectively. A new term, growth response map (GRM), was introduced and demonstrated by orthogonal projection of three-dimensional GR plots to provide time-specific information on environment performance. The outcome of this research can be extended and used in decision support programs for energy management in greenhouse and other types of controlled environment plant production systems (CEPPS).