Evaluation of long-term climate change impact on the growing season and water use of mature pecan in Lower Rio Grande Valley

Pecan is a major crop in the Lower Rio Grande Valley (LRGV), New Mexico. Mexico currently largest pecan producer United States. also considered water user which can consume as much 1200–1300 mm of during growing season. Climate change have significant potential impact on requirement well its productivity and cost production. This study evaluates climate effects duration season (DGS) LRGV over period 1901–2019. Temperature data for was used to identify DGS. Hargreaves–Samani model calculate reference evapotranspiration (ET0). Daily coefficient (Kc) calculated using developed regression relating Kc cumulative degree days (GDD). The Mann-Kendall Sen’s methods were applied determine if there positive or negative trend DGS, ET0, actual (ETa). Statistical results showed decreasing DGS 1901–1950 whereas an increasing detected 1950–2019. Like variations, trends both seasonal ET0 ETa observed first 50 years rest with 99% confidence level, respectively. Results increase 124 between 1950 2019. that been occurring period, continuous increases may bring changes requirement, economics production other horticultural challenges such insufficient chill flowering, increased vivipary, delayed prolonged harvest.