Improving Water Productivity in Greenhouse and Open-Field Vegetable Crops

Abstract Improving water productivity in arid and semi-arid regions by using clean technologies and sustainable solutions in agri-food systems is essential for food security and protecting the environment. A series of studies were conducted to improve water productivity in protected cultivation and open-field agriculture. This includes adding biochar as soil amendments and sub-drip irrigation for different vegetable crops. Also, some irrigation practices, such as regulated deficit irrigation (RDI) and partial root-zone drying (PRD), were tested using different irrigation water quality. When 5% biochar was applied with fresh water increased tomato plants' yield under various irrigation treatments. The yield increased by 4.60%, 16.74%, 8.67%, and 2.97% at 100%, 80%, 60%, and 40% ETc, respectively. Tomato plants treated with biochar and irrigated with fresh water under 40% deficit irrigation showed a remarkable 97.02% increase in water use efficiency compared to those under full irrigation. Adding other organic materials, such as compost, also improved WUE. Compared to the control treatment, biochar 2% + Compost 2% increased WUE by 54.0%. PRD consistently achieved greater irrigation efficiency, especially with subsurface irrigation. Sub-drip Irrigation (SDI) was also tested in an open-field study with potato plants. An SDI system with full irrigation (I100) maximized potato yield, while deficit irrigation (I50) improved water use efficiency (IWUE).