Yield and Yield Components of Four Spring Wheat Cultivars Grown Under Three Tillage Systems1

Abstract Soil erosion is a serious problem in the wheat (Triticum aestivum L.) producing areas of the Palouse Region of the Pacific Northwest. A field study was conducted under three environmental conditions [a Palouse silt loam (Pachic Ultic Haploxerolls, fine‐silty, mixed, mesic) during 1980 and an Athena silt loam (Pachic Haploxerolls, fine‐silty, mixed, mesic) during 1979 and 1980] to determine the effects of three tillage systems on grain yield and yield components of four soft white spring wheat cultivars, WS‐1, Urquie, Fielder, and Walladay. The tests were conducted using conventional (fall plow and spring disk), conservation (fall chisel and spring disk), and no‐tillage (standing stubble) tillage systems. Average grain yields with no‐tillage and conservation tillage were significantly greater than yields using conventional tillage. No‐tillage increased test weights while reducing tillage operations significantly reduced the number of spikelets per head, but increased the 100‐seed weight. Tillage practice had no significant influence on heads/m2, seeds per spikelet or seeds per head. Environment significantly influenced all yield components but not grain yield itself. There were significant differences in yield and yield components among the cultivars examined. Cultivar ✕ tillage interaction for yield (p ≤ 0.06) and test weight (p ≤ 0.03) were significant when examined across all environments. These findings show that no‐tillage spring wheat yields were equal to or greater than that obtained with conventional tillage. Significant cultivar ✕ tillage interactions for yield and test weight emphasize the need to evaluate individual spring wheat cultivars for specific tillage conditions.