Plant production, Plant physiology - Nutrition, varieties, etats de l' ouest eu, type de sol textural, crop yield, triticum aestivum, western states usa, mulching, dosis de aplicacion, cultivo, textural soil types, lluvia, paillage, variete, profundidad, nutrient uptake, rendement des cultures, application rates, soil morphological features, cultivation, rain, variedades, caract morfologicas del suelo, ploughing, profondeur, rendimiento de cultivos, dose d' application, estados del oeste eua, nitrogen fertilizers, engrais azote, aradura, tipos texturales de suelos, cubrimiento del suelo, labour, depth, trait morphologique du sol, absorption de substances nutritives, abonos nitrogenados, pluie, pratique culturale, and absorcion de substancias nutritivas
references. AVAILABILITY: US (DNAL 56.9 SO3).
Wheat (Triticum aestivum L.) response to N in semiarid climates is highly influenced by precipitation and tillage, leading to inefficient use of fertilizer and greater potential for groundwater contamination. To improve fertilizer recommendations, we measured white winter wheat response to 45, 90, 135, and 180 kg N ha-1 for 10 crops grown in a wheat-fallow rotation with three tillage treatments, one conventional (moldboard plow) and two stubble-mulch (offset disk, subsurface sweep). The soil was a Walla silt loam (coarse-silty, mixed, mesic Typic Haploxeroll) with three depths to bedrock (208, 132, and 111 cm). Grain yield averaged 5.51, 4.07, and 3.55 Mg ha-1 with above- (147), near- (88), and below-normal (61 mm) growing-season precipitation (GSP). Nitrogen increased yield 3.0, 1.9, and 0.4 Mg ha-1 in these precipitation regimes. Grain yield was not affected by soil depth when GSP was above normal, but 10 to 20% less on the shallower soils when GSP was below normal. There was a trend towards higher yield with conventional tillage when GSP was above normal. The amount of applied N required for optimum yield was > 135 kg N ha-1 with above-normal GSP and