Browsing by Author "Creech, Cody F."

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Influence of planting date and herbicide program on Amaranthus palmeri control in dry bean
(Cambridge University Press, 2021-11) Beiermann, Clint W.; Creech, Cody F.; Knezevic, Stevan Z.; Jhala, Amit J.; Harveson, Robert; Lawrence, Nevin C.
Late-emerging summer annual weeds are difficult to control in dry bean production fields. Dry bean is a poor competitor with weeds, due to its slow rate of growth and delayed canopy formation. Palmer amaranth is particularly difficult to control due to season-long emergence and resistance to acetolactate synthase (ALS)-inhibiting herbicides. Dry bean growers rely on PPI and preemergence residual herbicides for the foundation of their weed control programs; however, postemergence herbicides are often needed for season-long weed control. The objective of this experiment was to evaluate effect of planting date and herbicide program on late-season weed control in dry bean in western Nebraska. Field experiments were conducted in 2017 and 2018 near Scottsbluff, NE. The experiment was arranged in a split-plot design, with planting date and herbicide program as main-plot and subplot factors, respectively. Delayed planting was represented by a delay of 15 d after standard planting time. The treatments EPTC + ethalfluralin, EPTC + ethalfluralin followed by (fb) imazamox + bentazon, and pendimethalin + dimethenamid-P fb imazamox + bentazon, resulted in the lowest Palmer amaranth density at 3 wk after treatment and the highest dry bean yield. The imazamox + bentazon treatment provided poor Palmer amaranth control and did not consistently result in Palmer amaranth density and biomass reduction compared with the nontreated control. In 2018, the delayed planting treatment had reduced Palmer amaranth biomass with the pendimethalin + dimethenamid-P treatment, as compared with standard planting. Delaying planting did not reduce dry bean yield and had limited benefit in improving weed control in dry bean.
Planting date and seeding rate of field pea in the semi‐arid high plains of Nebraska
(Wiley, 2020-11) Koeshall, Samuel T.; Easterly, Amanda C.; Werle, Rodrigo; Stepanovic, Strahinja V.; Creech, Cody F.
Results from initial experiments in western Nebraska suggest that opportunity exists to decrease seeding rates of pea (Pisum sativum L.) to optimize yield while maintaining partial net return. Refined planting recommendations, especially planting time, are still largely unknown for western Nebraska. This experiment evaluated the effects of seeding rates and planting dates of pea on emergence, grain yield, and grain yield components. Two locations in Nebraska were evaluated in 2018 and 2019. Treatments consisted of three planting dates and five seeding rates arranged as a split-plot design. Emergence was measured in each plot until emergence stabilized. Whole plant biomass, pods plant-1, seeds plant-1, and harvest index were recorded at harvest. Planting later resulted in increased plant density and decreased time to 50 and 90% emergence. Planting date also changed the economically optimal plant population. At Sidney in 2018, optimal plant population changed from 96 plants m-2 (Early) and 115 plants m-2 (Late) to 82 plants m-2 (Middle). Partial net return was increased by $26.74 ha-1 and $65.43 ha-1 with the middle planting date over the early and late planting dates. Across three site-years, the economically optimal plant population only varied by 4 plants m-2 between the three planting dates. Later planting improves percent emergence without reducing yield. Seeding rates that have been adjusted for expected germination should target a population between 70 and 109 plants m-2 to optimize partial net return. Final plant population influences grain yield more than planting date, although both affect yield response.
Replacing fallow with field pea in wheat production systems across western Nebraska
(Wiley, 2022-11) Koeshall, Samuel T.; Easterly, Amanda C.; Werle, Rodrigo; Stepanovic, Strahinja; Creech, Cody F.
Integration of field pea (Pisum sativum L.) (FP) into dryland cropping systems has increased due to ecological and economic benefits, paired with a growing market for pea-derived products. Challenges exist in the High Plains that limit the integration of crop rotations to replace fallow periods with FP in wheat (Triticum aestivum L.)-based systems. This experiment compares chemical summer fallow to FP in a fallow–wheat rotation at two locations in western Nebraska. Soil water content, soil fertility, N mineralization, FP yield, and subsequent hard red winter wheat (HWW) yields were recorded. Subsequent HWW yields were not different between crop sequences (P = .42). The interaction of site-year with crop sequence explained the HWW yield differences (P = .0005), mostly due to precipitation variability among site-years. Most soil parameters tested only showed a main effect of date due to temporal changes in soil nutrient cycling. Replacing summer fallow with FP resulted in reduced soil water content, however, that did not result in long-term moisture deficiency due to crop sequence type. System annualized gross revenue was equal to or greater for 2 site-years for FP compared with fallow, with an average increase of US$113.15 ha–1. Pea–wheat reduced annualized net losses in 1 site-year by $70 ha–1 compared with fallow–wheat in the "average" pricing model. Among 3 site-years and three pricing models, pea–wheat resulted in greater net profit or reduced net losses compared with fallow–wheat in 5 site-year comparisons.