Guayule biomass production under irrigation

Biomass, rubber, and resin yields of the drought-tolerant guayule plant (Parthenium argentatum, Gray) can be greatly enhanced with irrigation. In arid environments, guayule yield increases were closely related to the amount of water added. Nitrogen additions also increased yields whenever water availability was not a yield-limiting factor. Yield functions were derived using evapotranspiration, as well as water and nitrogen applications as the primary variables. Water use efficiencies for biomass production of irrigated guayule were in the order of 0·7 and 0·5 kg m^-3 for the Mesa and Yuma sites, Arizona, respectively. The efficiency values were lower than other crops grown in the same area. Yields at reduced rates, however, were obtainable even when the plants were under extreme water stress that would be totally damaging to other crops.