A comparison of forage yield and quality in a simulated graze-out for twelve varieties of hard red and white winter wheat

Six hard white winter wheat varieties (Burchett, Lakin, NuFrontier, NuHills, Nu- Horizon, and Trego) and six hard red winter wheat varieties (2137, Jagalene, Jagger, OK101, Stanton, and Thunderbolt) were planted in two southwestern Kansas counties, Clark and Stanton, to compare simulated graze-out forage yield and quality. Four replicated plots were planted in September 2003 for each variety at each location. Forage samples were collect from each plot during December 2003, March 2004, and April or May 2004. Dry matter content, dry matter yield, crude protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN), net energy (NEm, NEg), relative feed value (RFV), and nitrate nitrogen were determined. Significant location-by-variety interactions were observed for most factors. Although significant differences in crude protein and energy were detected, it is unlikely that the performance of stock cattle would differ when grazing each of the varieties because the lowest crude protein concentration would support excellent gain, and because the differences in energy were relatively small

Nitrogen use and biomass distribution in culms of winter wheat populations selected from grain-only and dual-purpose systems

Beginning in late fall and ending at jointing in early spring, winter wheat (Triticum aestivum L.) crops in the southern Great Plains are often grazed by stocker cattle (Bos taurus L.) and then harvested for grain. Traditionally, dual-purpose (grazing plus grain) wheat cultivars are developed from a grain-only production system. Because culms of dual-purpose grown wheat may forfeit productivity gains for grain only developed cultivars, we evaluated N and biomass traits at anthesis and maturity for 12 sets of subpopulations (each set a unique genetic background) to test benefits of making selections from a dual-purpose system. Sets came from F2 sources and contained a "Base" F3 bulk population and F5 bulk populations mass selected from the F2 within grain-only and dual-purpose production systems. The 12 sets of subpopulations were evaluated in grain-only and dual-purpose production systems in 2001-2002 and 2002-2003. At anthesis, main effects (year, system, genetic background, subpopulation selection environment) were significant for culm dry weight and N, and flag leaf dry weight. Among selections, differences for these traits were small (2.0-3.5%) with no difference between grain-only and dual-purpose selections; differences among genetic backgrounds, however, were large (21-30%). At maturity, differences (7.6-20%) for grain dry weight and kernel mass, harvest index (HI), N content, grain N, and N harvest index (NHI) of individual culms occurred among genetic backgrounds. Differences among subpopulations were smaller (1.4-4.5%) and significant for only culm and grain dry weight, kernel number and mass, and culm N content. Selections made from the dual-purpose environment performed similar to those from the grain-only environment when grown in either production system.Peer reviewedPlant and Soil Science

Grain Quality of Early Maturing Soybean Grown in Kentucky

Interest in grain quality of US soybean has grown in recent years. For example, in 1990, there was much interest in component pricing of soybean grain, Under that plan, growers would be paid a price for their grain that reflected the value of the protein and oil it actually contained, rather than the common price paid to all growers, regardless of any variation in protein and oil content. However, the soybean processing industry is evidently not excited about the complexity of testing individual lots for protein and oil and keeping track of pricing structures depending on those results. As a result, component pricing has yet to happen

Genetic trends in winter wheat yield and test weight under dual-purpose and grain-only management systems

Wheat (Triticum aestivum L.) cultivars of the southern Great Plains are traditionally bred in environments managed for grain production only but are commonly grown for the dual-purpose of producing winter forage and grain from the same crop. To what extent grain yield and test weight are consistently expressed in those environments requires investigation relative to long-term attempts to improve them genetically. A historical set of hard red winter (HRW) wheat cultivars was evaluated under grain-only and dual-purpose management systems to compare their agronomic performance and derived estimates of genetic progress. Separate experiments were established for each system featuring whole-plot treatments of a foliar fungicide and split-plot treatments of 12 cultivars. The study was conducted for 3 yr at the Wheat Pasture Res. Ctr. near Marshall, OK. Dual-purpose experiments were generally grazed from November through February. Yield in the grain-only system improved 18.8 kg ha^-1 yr^-1, equivalent to 1.3% of the mean yield for Turkey. The rate of progress in the dual-purpose system was significantly lower at 11.3 kg ha^-1 yr^-1, equivalent to 0.9% of the mean for Turkey. Management for grazing had a more profound influence on estimates of yield improvement than did management for disease protection. Linear trends in test weight were not evident under either system, nor were cultivar differences influenced by management system consistently across years. Breeding practices should emphasize selection for grain yield in both environments if future progress is to be maximized in both.Peer reviewedPlant and Soil SciencesAnimal Scienc

Fall forage biomass and nitrogen composition of winter wheat populations selected from grain-only and dual-purpose environments

Winter wheat (Triticum aestivum L.) is the foundation of many agricultural enterprises in the southern Great Plains and is grown primarily as either a grain-only (GO) or a dual-purpose (DP, grazing plus grain) crop. Traditionally, cultivars are developed in GO systems. Because of genotype X system interactions, the DP environment may compromise gains in grain yield accrued in GO-developed cultivars. Forage traits for 24 sets of populations (each with unique pedigree) were used to test benefits of tailoring breeding programs for DP wheat. Each set came from the same F2 source and contained a base (B) F3 bulk population and F5 bulk populations mass selected from the F2 within either a GO or DP system. Forage biomass and forage total N and nitrate were measured at the start of fall grazing. Nearly always, the effect of selection environment was consistent across genetic backgrounds. Effect of selection environment on forage biomass of each nursery was significant at P = 0.09 and P = 0.07. In 2001, DP-derived populations produced about 5% less than GO-derived populations; in 2002, the selection effect was not significant (P = 0.38 and 0.30). Selection environment had a significant effect on forage total N, but not nitrate levels. Total N in DP selections was slightly greater (2.5%, P < 0.05) than those from B and GO selections. Forage nitrate was affected by genetic background; mean nitrate-N among the 24 backgrounds ranged from 1.3 to 3.1 mg g^-1 in 2001 and 0.4 to 1.3 mg g^-1 in 2002. Selection in the DP system appears to offer equal or slightly less fall forage biomass without greatly changing forage total N and nitrate concentrations.Peer reviewedPlant and Soil Science

Rhizosphere-mediated effects of the invasive grass Bromus tectorum L. and native Elymus elymoides on nitrogen cycling in Great Basin Desert soils

Background and aims: There is evidence that the invasive grass Bromus tectorum can affect soil nitrogen (N) cycling, possibly leading to a positive plant-soil feedback. Rhizosphere priming of N mineralization could provide a mechanistic explanation for such a feedback. Methods: We conducted a greenhouse study to isolate rhizosphere effects on N cycling by the invasive annual grass, Bromus tectorum L., and the native perennial grass, Elymus elymoides (Raf.) Swezey, in invaded and uninvaded soils. We compared the rhizosphere priming effect (RPE) on N mineralization by species and the distribution of N in various pools by planting treatment and soil type. Results: B. tectorum had a negative RPE (−23 and −22&nbsp;% in invaded and uninvaded soils, respectively), while E. elymoides had no significant RPE. B. tectorum was more competitive over E. elymoides in invaded compared to uninvaded soil. Conclusions: B. tectorum had a negative effect on soil N availability via root-mediated processes, even though its growth and competitiveness increased in invaded soils. Positive plant-soil feedback effects of B. tectorum may be mediated by aboveground inputs rather than belowground and/or depend on site-specific conditions

Evaluation of phosphorus extracted by routine laboratory procedures from Arizona soils

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