Evaluation of citrus grove floor management strategies for water use efficiency and conservation

Abstract

Perennial crops require water year-round, straining water resources, particularly in arid and semi-arid regions throught the world. Of those regions, the Lower Rio Grande Valley of Texas, USA, depends on flood irrigation to meet water demands of crops. Approximately 60–70% of citrus producers use flood irrigation to irrigate their groves, which is less efficient than other irrigation methods such as micro-jet or drip irrigation. Flood irrigation is to reduce cost, equipment, and energy required, and no land needs to be taken out of production to be used for holding ponds. Therefore, conservation practices that are adapted for flood irrigation are necessary in these areas where infrastructure is less conducive to other practices. Water use efficiency and potential water savings in different grove-floor management strategies, citrus tree growth, soil moisture, and irrigation volume were measured over the course of 3 years (from establishment to first harvest) in four different grove floor management strategies. These strategies, flat-bed no plastic mesh groundcover (traditional), flat-bed with plastic mesh groundcover, raised bed no groundcover, and raised bed with groundcover showed varying impacts on young citrus tree growth, soil moisture, and water savings over this study period. By the end of the study, 2.2% water savings (44,403 L over 4 years) were found in the flat bed with groundcover treatment compared to traditional grove floor management. This treatment also resulted in higher water use efficiency and greater initial growth of young citrus. Overall, the use of ground cover showed much potential for conserving water compared to traditional, uncovered flat bed management methods. These grove floor management practices can improve tree growth and establishment in young citrus trees in addition to improving water use efficiency. However, it is yet to see how these benefits will translate to more mature trees.