Initial Evaluation of the Merit of Guar as a Dairy Forage Replacement Crop during Drought-Induced Water Restrictions

Abstract

Dairy is the largest sector of the agricultural industry in New Mexico, but the sector’s need for high quality forage in the face of ongoing drought and climate change causes concern. The economic merit of using guar to replace alfalfa under imposed constraints in irrigation water availability is evaluated. Nutritional quality of guar (Cyamopsis tetragonoloba L.) grown at the NMSU Agricultural Science Center at Clovis was estimated using Near Infrared Spectroscopy (NIRS) analysis. Results show that 45.6 percent of analyzed samples were comparable to Supreme or Premium alfalfa (Medicago sativa) hay using Relative Feed Value index, and 23.7% met this criteria using crude protein. While alfalfa uses 4.4 acre-feet of water (approximately 5400 cubic meters) per season, the guar sampled used 5 inches (500 cubic meters) of applied irrigation. Microsoft Excel Version 2404 LP Solver was used to identify an optimum crop mix of alfalfa and guar under different levels of irrigation water constraints. With increasing levels in modeled irrigation restrictions, the use of guar increased the potential forage production by 3% under a 0.4 acre-foot restriction up to almost 59% under a 1.5 acre-feet irrigation water limit. Our results merit additional research, including forage trials to determine the impact of guar forage on milk production and further agronomic research into growing guar to maximize forage yield.