Indirect Estimation of Wheat‐Hairy Vetch Ratios in a Mixed Stand 1

Forage researchers often times work with mixed grass and legume stands. The relative proportion each species contributes to the stand is an important determinant of forage yield and quality, but handseparating species is a time‐consuming and tedious task. A study was conducted to evaluate a laboratory technique for estimating wheat ( Triticum aestivum L.) and hairy vetch ( Vicia villosa Roth.) ratios in a mixed stand. Pure samples of two wheat cultivars and hairy vetch collected at the boot, milk, and soft dough stages of wheat maturity were mixed in known proportions and analyzed for total N concentration. The wheat and hairy vetch proportions were estimated by solving simultaneous equations for each mixture. The total N method was an effective means of estimating grass‐legume ratios in this two‐component mixture. The deviation of a predicted individual observation ranged from 1.46 to 5.50 percentage units. Precision of the method was not influenced by the wheat cultivar utilized or by the maturity stages selected. Total N determination is commonly done as a part of forage quality assessment in many experiments. Only a few additional total N determinations on the pure grass and legume components are necessary to estimate grass‐legume ratios.