Deficit Irrigation and Root Zone Soil Thermal Regimes in Water Limited Agriculture: A Review

Abstract

Soil thermal properties strongly influence root-zone temperature and crop performance under deficit irrigation, but are rarely considered in irrigation design for water-scarce regions. This systematic review synthesizes studies (2020 onwards) on how deficit irrigation and water-saving practices modify soil thermal properties and coupled soil water–heat dynamics in irrigated agroecosystems. Eligible field and modelling studies on irrigated crops in arid and semi-arid regions were identified in major databases using predefined search terms for deficit irrigation, soil temperature, and soil thermal properties, and were screened using explicit inclusion criteria. The evidence shows that deficit irrigation typically lowers soil moisture, reduces thermal conductivity and heat capacity, and increases diurnal soil temperature ranges, with effects shaped by soil texture, irrigation method, and emitter placement. Localized and subsurface irrigation, mulches, organic amendments, and pre-season irrigation can create deeper, moist, thermally buffered root zones that sustain water productivity under moderate deficits, especially when combined with coupled water–heat modelling and thermal sensing for scheduling. These findings highlight the need to explicitly incorporate root-zone hydro-thermal behavior into deficit irrigation design for water-scarce regions.