Fallow management and nitrogen fertilizer influence winter wheat kernel hardness

Kernel hardness is an important grain attribute for wheat (Triticum aestivu m L.) quality and marketing in the USA. The objective of this study was to characterize the effects of fallow management moldboard plow (plow), subtil lage (subtill), and no-tillage (no-till)-and N fertilizer (0 and 45 kg N ha (-1)) on winter wheat kernel hardness, as measured by the Single Kernel Cha racterization System (SKCS). Rainfed field studies were conducted with 'Sio uxland' hard red winter wheat from 1995 to 1997 on an Alliance silt loam (f ine-silty, mired, mesic Aridic Argiustoll) near Sidney, NE. In 1995 and 199 6, the kernel hardness index was increased from a 2-yr average of 46.0 to 5 5.2 by the addition of 45 kg N ha(-1), but N fertilizer treatment had no ef fect on kernel hardness in 1997 when the average kernel hardness index was 72.9. The effect of fallow management on kernel hardness varied from gear t o gear. Kernel hardness was positively correlated with grain protein in 199 5 (r = 0.93) and 1996 (r = 0.94)? but no meaningful relationship was observ ed in 1997, Half of the grain samples analyzed by the SKCS in 1995 and 1996 were classified as either soft or mired wheat. This study suggests that ke rnel hardness is affected by a number of factors beyond genetics including N management, tillage system, pest infestations, environment, and their int eraction. Growers may find that meeting proposed new grain standards is mor e complex than merely selecting the right cultivar.