Preliminary Mapping of the Spatial Variability in the Microclimate in Tropical Greenhouses: A Pepper Crop Perspective

Abstract

The objectives of this experiment were to (1) discern the spatial variability in climatic parameters within a greenhouse throughout different phenological stages of pepper cultivation and (2) develop an empirical model aimed at establishing predictive equations for temperature, relative humidity, vapor pressure deficit, and crop evapotranspiration (ETc) within the greenhouse considering the climatic parameters recorded on the outside. The experiment was conducted in the coastal area of Ecuador within a bamboo-constructed greenhouse facility. Pepper plants were cultivated in plastic bags using a specific cultivation medium common in Ecuador and a fertigation system. Climatic parameters were monitored within the greenhouse using data loggers, and the external conditions were recorded using an external meteorological station throughout the duration of the pepper cultivation. Statistical analyses revealed correlations between internal climatic parameters and plant growth stages, as well as external climatic conditions. The spatial distribution analysis of climatic parameters within the greenhouse revealed that the lowest values for temperature (27 °C) and vapor pressure deficit (VPD) (1.25 kPa) and the highest values for relative humidity (RH) (68%) were observed on the northwest corner of the greenhouse. This observed pattern was linked to the prevailing wind direction (south–east (SE)) outside the greenhouse. Stepwise regression analyses identified significant outdoor climate variables (RH, temperature, VPD, and instantaneous wind speed (WS) Inst) in the climatic conditions recorded within the greenhouse.

Keywords

• <i>Capsicum annuum</i>
• climatic parameters
• crop evapotranspiration
• phenological stages
• modeling