INFLUENCE OF SOIL AND N-FERTILIZER ON PERFORMANCE OF BARLEY AND SPRING WHEAT CULTIVARS

Fields often include several different soils with contrasting chemical and/or physical characteristics which may influence crop performance. Field experiments were conducted (i) to quantify differences in spring barley (Hordeum vulgare L.) and spring wheat (Triticum aestivum L.) grain yield, test weight, and protein on contrasting soils within single fields, and (ii) to determine interactions between N fertilizer and spring wheat cultivar performance on several different soils. Twelve barley and twelve wheat cultivars were established in a randomized complete block design on three different soils in a field during 1987. Soils affected grain yield, test weight, and protein of the barley cultivars by as much as 485 kg ha-1, 38 kg m-3, and 16 g kg-1, respectively. Corresponding differences for spring wheat were 456 kg ha-1, 50 kg m-3, and 16 g kg-1. Grain yield of one barley cultivar differed by as much as 966 kg ha-1 across three soils, while wheat grain yield differed by as much as 1271 kg ha-1. Significant soil X cultivar interactions were measured for at least one grain parameter with both crops (P < 0.10). In another experiment conducted nearby in 1987 and 1988, grain yield, test weight, and protein differed by as much as 2217 kg ha-1, 16 kg m-3, and 15 g kg-1, respectively, among soils where different spring wheat cultivars and several rates of N fertilizer were evaluated. Cultivar and N rate significantly influenced grain yield and test weight during both years and protein during 1987. Soil x N rate interactions were highly significant for both yield and protein during 1988, but not for test weight; nor were the soil x N rate interactions significant for any grain parameter during 1987. Soil x cultivar interactions were significant for both test weight and protein during both years, whereas cultivar x N rate interactions were not significant. These data suggest that in some instances soil conditions should influence cultivar recommendations.