The adaptability of irrigated agriculture in the High Plains region of Texas in the 1970-80 period is analyzed by estimating Allen partial elasticities of substitution for five key inputs (water, labor, center pivot, furrow and wheel roll systems) used to produce two crops (cotton and grain sorghum). The results indicate that farmers have adapted to changes in a manner generally consistent with prior expectations concerning complementarity and substitutability among inputs. The output-constant price elasticities of water demand was statistically significant but relatively small (-25).