Assessment of influence of soil texture and salinity in pecan orchards of southern New Mexico and western Texas

Abstract Pecans [ Carya illinoinensis (Wangenh.) K. Koch] are a significant cash crop in the southwest of the United States, and soil properties, irrigation quality, and nutrient availability influence their production. This study was conducted in six orchards along the Rio Grande River in southern New Mexico and southwest Texas during the 2015 and 2016 growing seasons. The objective was to assess the effects of soil texture, irrigation with brackish groundwater, and nitrogen dynamics on pecan kernel percentage (KP), nut length (NL), and nut number per 1 kg (NP). Soil samples were collected from 0‐ to 120‐cm depth and analyzed for electrical conductivity (EC), nitrate (NO 3 − ), total Kjeldahl nitrogen (TKN), and ammonium (NH 4 + ) in February, June, and October. Results showed that NO 3 − concentrations peaked at 286 mg/kg in October 2016 at 20‐ to 40‐cm depth in Fabens 1 orchard, while TKN varied widely, with the highest value (1067 mg/kg) in Fabens 2 orchard at 0‐ to 20‐cm depth. Anthony orchard, with loamy soil and an EC of 5 dS/m, had the longest NL (41.34 mm), the lowest NP (146), and the lowest KP (53.16%). In contrast, Canutillo orchard, with clay loam soil and an EC of 4 dS/m, had the highest KP (57.66%) but shorter NL (27.94 mm). Orchards in sandy loam soils with lower EC showed higher nut production, while loamy soils with higher EC promoted longer nuts. These findings underscore the need for site‐specific nitrogen and salinity management strategies to optimize pecan yield and quality.