Relating On-Farm Level Irrigation Water Use to ‘Rio Red' Grapefruit Pack-Out

Citrus production in the Lower Rio Grande Valley (LRGV) of South Texas is solely dependent upon surface water sources from the Rio Grande River.  This region of the United States is experiencing the third fastest growing population which receives its municipal water needs from the same water source.  In effort to preserve citrus production in the LRGV a 5-year (2005-2009) investigation was performed with growers on field demonstration sites ranging from 2 to 20 ha in size.  Four main irrigation systems were monitored during this study: traditional large-pan flood (Fld), narrow border flood (BFld), Microjet sprinkler spray (MJ), and Drip (Drp) irrigation. Four demonstration sites were created for each irrigation system. Total irrigation water use was monitored performed and compared to ‘Rio Red’ grapefruit citrus yields.  Data was collected from growers on citrus ‘pack-out’ from the packing sheds, and economic assessment was performed to demonstrate the most cost effective irrigation method to 1) reduce irrigation water, and 2) maximize yield and profit margin for the grower.  All irrigation methods saved water in comparison to tradition flood irrigation (Fld), with an average annual water savings of 23.4, 31.0, and 34.8 cm for BFld, MJ, and Drp, respectively.  The highest average citrus yields and a greater portion of grapefruit going to the ‘fancy’ classification and maximum profit margin came from BFld producers, followed by MJ, Drip and lastly Fld.  Our results demonstrate that LRGV growers can save water and receive higher production and profits switching from Fld to BFld irrigation methods.

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