Energy Nexus (Sep 2022)
The combined effect of water management and environmental control on the planting of two varieties of garden egg in a partially shaded greenhouse: an energy and yield indicator analysis
Abstract
The objective of this study is to investigate the performance of partially shaded solar greenhouse and water management on the growth and bioactive yield of garden eggs under micro climate management. For this reason, two local varieties of garden egg (Solanum aethiopicum and Solanum gilo) were planted in a partially shaded natural convention greenhouse at Umudike South Eastern Nigeria and nurtured for four months from June to September before harvest. The plants were supplied water at 50, 70 and 100% field capacity with the internal condition of the greenhouse naturally controlled by the ambient condition. The evaluation parameters were the average monthly heat load flux, ventilation flux, transpiration rate, plant growth parameters, and phytochemicals and anti-oxidants characteristics of the fruits from the garden egg in comparison with the open field plantation. Thermal analysis showed that an increase in temperature and lower relative humidity increases the evapotranspiration rate in the greenhouse. The average sensible and latent heat load ranged from 10.9 to 121.3 W/m2 and 21.94 to 63.56 W/m2 respectively. In contrast, the average monthly ventilation flux which was deduced as a function of heat load ranged from 5.307 × 10−3 to 8.053 × 10−3 m3/m2.s. While water management and greenhouse had negative effects on most of the growth parameters of the garden egg, they significantly increased the antioxidant contents in the garden egg, particularly total phenolic contents (TPC) and total flavonoid contents of fruits which is a quality needed for a healthy body. This shows that climatic control and water management influence garden egg quality more than the growth parameters. The data from this study will enhance understanding of the influence of water stress on garden egg yield under controlled environmental conditions, which might be important in providing the needed nutrient for healthy body.
