Rapid Estimation of Forage Biomass in Wheat and Other Annual Cool-Season Winter Grasses.

Annual winter grass cropping systems offer numerous environmental, agricultural, and animal husbandry benefits apart from providing sustainable economic paybacks. The choice and cultivation of a specific forage or dual-purpose winter small grain crop depends mainly on perpetual forage production across seasons and also grain yield, if opted. It is critical to precisely estimate early vigor, forage biomass, and regrowth; but the prevailing methods are subjective, laborious, and time-consuming. The objective of the current study was to evaluate new indirect methods of estimating forage biomass in comparison with the prevalent methods such as visual scores and destructive sampling (hand-clipping). A two year, multi-location, simulated-grazing study was conducted at distinct environments representing the Texas High Plains (Amarillo, TX) and the Texas Rolling Plains (Lockett, TX). The study comprised 32 winter small grain forage crops dominant in the US Southern Great Plains including wheat, rye, oat, barley, and triticale. The results suggests that digital imaging and normalized difference vegetation index (NDVI) data using GreenSeeker provided good estimates of early vigor, ground cover, biomass growth rates, and forage yield. Methods demonstrated high technical repeatability and yielded high R² values when regressed with hand-clipped biomass at both environments (0.67 and 0.89). NDVI data was also found to be useful in detecting winter-hardiness in the germplasm and also recovery rates from freeze injury. Swiftness, amenability and accuracy of the methods proved extremely valuable in screening breeding populations for traits related to high biomass production under grazing or dual-purpose cropping systems.