Integrated energy-water assessment framework for calcium deficiency control in agricultural greenhouses: A data-driven model predictive control approach

Widespread calcium deficiency in modern agriculture impacts plant health and crop productivity, as seen in cucumber crops with leaf yellowing, revealing broader nutritional implications. Calcium uptake, crucially linked to transpiration-driven water flow, requires thorough temperature and irrigation management. However, rapid water uptake, driven by high transpiration rates in intense sunlight conditions such as the case in hyper-arid regions, can hinder calcium absorption. In response to this challenge, this study presents an innovative approach using data-driven Model Predictive Control (MPC) to manage calcium deficiency in hyper-arid region greenhouses, integrating two MPC systems for optimal irrigation and temperature control. The irrigation control MPC relies on a comprehensive set of input variables, including microclimate data along with hyperspectral imaging data, processing the latter to calculate vegetation indices for analysing different plant characteristics. This system dynamically regulates irrigation to optimise soil moisture levels and enhance subsequent calcium uptake by plants. Concurrently, the temperature control MPC employs a set of input parameters, including solar radiation, external temperature, humidity, fan speed, and HVAC control. By considering these factors, the MPC system effectively controls temperature within the greenhouse, ensuring an optimal microclimate for calcium uptake. This integrated energy-water assessment framework offers a holistic and technologically advanced approach to calcium deficiency control. It leverages cutting-edge data-driven techniques, microclimate sensors, hyperspectral imaging, and advanced control strategies, exemplifying the use of Agriculture 4.0 and precision agriculture, to create an optimised greenhouse environment that enhances calcium uptake in plants. The findings of this study have significant implications for sustainable agriculture, including improved crop health and yields, decreased resource use, and enhanced food security.