Utilizing the abundant solar radiation for optimizing the planting space of tomato (Lycopersicon esculentum) var. Rita under greenhouse conditions

Solar radiation plays an important role in plant growth through the photosynthesis process and especially in plants grown under greenhouse conditions where the photosynthetic light source is reduced compared to plants grown under natural conditions. An increase in sowing density where the abundant solar radiation source as the study area is considered as an enhanced solution for optimizing crop productivity in the context of growing world food demand. The aim of the study is, therefore, to determine the optimal sowing density (OSD) of tomatoes grown in a greenhouse under the Smart Control System (SCS) to monitor irrigation amount and environmental factors. The work was deployed with seven different sowing densities varying from 25000 to 50000 cuttings/ha at household farming in Don Duong district of Lam Dong province, Vietnam, lasting from the end of January to the mid of June 2020. An auto irrigation system is installed under the plastic mulches to provide water amounts varying from 1.0 to 1.3 L/h depending on actual weather conditions and each growth stage. The analysis shows that between the tested densities, 25000 cuttings/ha is enhanced sowing density of optimal market productivity (180 t/ha) while other tested densities obtained larger diameter and weight per fruit, but the market productivities were significantly lower. Through experiment can confirm that with the abundant solar radiation and the use of a Smart Monitoring System, a density of 25000 cuttings/ha could enhance a novel cultivation solution for the tomato plants to contribute optimal market production with increased economic efficiency.