El Niño Southern Oscillation Effects on Dryland Crop Production in the Texas High Plains

Abstract

Risk averse dryland crop management in the U.S. southern High Plains stabilizes annual yields, however in some years the full yield potential is unrealized thereby reducing the overall cropping system productivity. Equatorial Pacific sea surface temperature anomalies (SSTA) systematically couple with the atmosphere to produce predictable El Niño‐Southern Oscillation (ENSO) weather in much of North America that could be exploited for improved crop management. Our objective was to evaluate ENSO effects on site‐specific growth and yield of wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench] in a dryland wheat–sorghum–fallow (WSF) rotation from 1954 to 2011. Measurements from contour farmed terraces were grouped by common ENSO phase years based on 3‐mo classification ending in June (April–June, AMJ) or August (June–August, JJA) that permits timely management of sorghum or wheat. Compared with years classified during September to November (SON) or mature ENSO phases, the JJA classification identified 78 and 68% of common La Niña and El Niño years, respectively, and may have potential application to wheat management. Poor agreement between SON and AMJ phase classifications reduced common La Niña and El Niño years to 61 and 53% respectively, and may limit grain sorghum management. Compared with La Nina, wheat growing‐season precipitation increased 31% for El Nino and contributed to a 55% increase in detrended grain yield differences. For the Texas High Plains, the ENSO phase effects on sorghum grain yield were less pronounced than for wheat, suggesting ENSO based management is better suited to wheat.Core Ideas El Niño phases affected site‐specific rain and crop yield of a 58‐yr field test. Wheat but not sorghum yields responded significantly to El Niño conditions. Predicted El Niño phase has the potential to guide site‐specific wheat management.