Sainfoin stand termination: Variable herbicide efficacy in field conditions

Abstract Effective termination of perennial forage legumes is a critical step in a crop rotation system, particularly in arid and semi‐arid regions where soil moisture conservation and timely establishment of subsequent crops are essential. Sainfoin ( Onobrychis viciifolia Scop.), a deep‐rooted, drought‐tolerant forage legume gaining renewed interest among producers, presents significant challenges for stand termination. This 1‐year field study evaluated the efficacy of multiple herbicides applied at varying rates and two application timings, under arid conditions in Wyoming. Results showed that all herbicides significantly ( p < 0.001) reduced fresh biomass yield of sainfoin compared to non‐treated with varying levels of control. Glyphosate at 4259 g ae ha − 1 applied after both first‐ and second‐cutting resulted in the greatest suppression, with an 84% (first‐cutting) and 95% (second‐cutting) reduction in fresh biomass, likely due to enhanced translocation to meristematic tissues during the plant's active accumulation of root reserves. The results of this study indicate that it is feasible to terminate sainfoin with herbicides.