Pasture-based livestock production is impacted by management and weather. In pastures, there is conflict between leaf retention for plant growth and leaf harvest for animal nutrition. Defoliated pastures with low light interception (LI) may have a low forage growth rate (FGR), while excessive growth shades leaves, reducing FGR and resulting in an S-shaped regrowth curve. To optimize production, it is best to keep FGR linear. Three studies were conducted to evaluate the impact of management and weather on FGR. Replicated pastures were used to measure FGR when grazed from 25 to 10 cm and allowed to regrow. The impact of alternative defoliation timings and intensities on FGR were studied using clipped treatments at three recovery intervals and two stubble heights. Variability in FGR was studied using a field validated plant growth model. Of the 24 growth periods studied, two displayed exponential, 12 linear and 10 linear-plateau growth. There was no effect of FM on growth curve form. In May and June, LI increased with canopy height, up to 0.93. Stubble height and days of growth impacted FGR with an interaction. There was no treatment impact on root density. Weather caused variation in FGR. A low FGR risk occurs at high elevations; greater risk occurs east of the plateau.

Tillage type/timing and herbicide application date may change the amount and timing of N mineralization, altering fertilizer N needs for first‐year corn (Zea mays L.) following glyphosate [N‐(phosphonomethyl)glycine]‐resistant (GR) alfalfa (Medicago sativa L.). Studies were conducted in 2012 and 2013 in Utah. Yield, quality, and economic return of silage corn as affected by five tillage type/timings (fall conventional till, spring conventional till, fall strip‐till, spring strip‐till, and no‐till), three herbicide application dates for alfalfa termination (fall, spring, and in‐crop), and four N rates (0, 56, 112, and 224 kg ha⁻¹) were evaluated. Silage corn yield and quality following GR alfalfa was economically optimized without N fertilization regardless of tillage type/timing and herbicide application date. Thus, N from decomposing alfalfa can provide the full N requirement of first‐year silage corn following GR alfalfa. Estimated animal milk production ha⁻¹ of silage corn was greatest and similar for all herbicide application dates with conventional tillage and spring herbicide application with strip‐till and no‐till (26–38 Mg milk ha⁻¹), whereas an in‐crop herbicide application with strip‐till and no‐till resulted in the lowest estimated milk production (21–29 Mg milk ha⁻¹). Increased economic return for the in‐crop herbicide date by including economics from harvesting the first alfalfa cutting before planting corn mostly offset the reduced economic return of the lower silage corn yield. Therefore, an application of 2,4‐D (2,4‐dichlorophenoxyacetic acid) and dicamba (3,6‐dichloro‐2‐methoxybenzoic acid) in the fall, spring, or in‐crop to control GR alfalfa are good economic options for conventional tillage, strip‐till, and no‐till systems.