Wheat interactions with Italian ryegrass; forage production and quality in pure and mixed stands of wheat, oats, and ryegrass; and halosulfuron interaction with soils

摘要

A growth room experiment compared seedling growth after nine weeks of twowheat genotypes in pure cultures and mixtures with Italian ryegrass at a low phosphorus(P) level and the P level recommended by soil testing. At the recommended P level inboth pure and mixed culture, Mit, a semi-dwarf genotype, had a greater height, leaf area,tiller number, and dry weight of leaves, stems and roots than did Kharkof, a landrace.These results reflected the visual selection criteria for seedling vigor and tillering used inthe initial development of the semi-dwarf cultivars.Field experiments compared total dry matter, calories, and percent crude proteinand acid detergent fiber of oats, wheat, and ryegrass in pure culture and mixtures at fourlocations in central Texas at first clipping, second clipping, and unclipped. Although,forage yield was lower for the first clipping than the second clipping or the unclippedtreatment, the first clipping had the best forage quality. There was a strongenvironmental influence on yield and quality. The best forage was pure wheat at CollegeStation, pure ryegrass at Marlin, the wheat-ryegrass mixture at Temple, and pure oats at Thrall. Since Temple had the greatest yield of any site, the wheat-ryegrass mixturedemonstrated the highest yield potential.The soil adsorption characteristics of halosulfuron was examined using six soils.Soil adsorption of halosulfuron appeared to be a function of organic matter. Low Kf,adsvalues indicated that a relatively high plant availability of halosulfuron could beavailable for plant uptake. Sorghum produced in soils with a low organic matter contentmay experience injury because of the high plant availability.