PSII-15 Effects of Tillage Method and Fertilization Rate on Fall Performance of Stocker Cattle Grazing Wheat Pasture and Stand Performance

Abstract

Abstract The objectives of this study were to determine the effects of fertilization rate and wheat pasture establishment method on fall stocker and wheat stand performance. Twenty-four, 1.62-ha pastures were utilized, with 8 pastures per fertilizer (N) treatment. Fertilization consisted of urea applied at 50.44, 67.25, or 84.06 kg N/ha. To measure responses associated with tillage method, 2 fields from each N treatment were prepared using clean-till (CT, n = 6), and the remaining fields were prepared with a no-till (NT) method. Beef steers (278.51 ± 29.42 kg) were randomly allocated at a fixed rate of 2.47 steers/ha (4 steers/pasture), with a combined total of 240 steers used in fall of 2021 and 2022. Steers were weighed upon arrival, at turnout, every 28 days, and when pulled off pasture. Steers were pulled off pasture when forage mass (FM) became insufficient, or temperatures became too cold to support forage regrowth. Forage mass sampling was recorded with a 0.25 m2 plate meter. Sampling dates coincided with weigh dates. Twenty plate meter readings were taken in every field (600 readings in total per sampling date) and 0.25 m2 grass clippings were obtained from 15 fields every sampling date to form a regression curve to estimate FM. An analysis of co-variance using the Mixed Model procedure in JMP was used to analyze this data. Tillage method and N rate were fixed categorical and continuous covariates, respectively. Year was modeled as a random effect. Tillage × N interaction was used to examine differences in slope estimates for N rate between CT and NT. Non-significant interactions were removed from the model. Total weight gain per hectare and final weight were both greater in CT compared with NT (P = 0.01), More grazing days was observed with CT (P < 0.01), as well as a trend toward greater mean FM (P = 0.06). Ending FM was also greater for CT pastures (P < 0.05). No significant effects from tillage were found for initial weight, average daily weight gain, initial FM, or FM slope change. No differences (P > 0.1) among responses were associated with a linear response to N rate. In conclusion, CT demonstrated greater performance than NT, with CT having greater FM response, more grazing days, and greater body weight gain per hectare, and N rates greater than 50.4 kg/ha did not appear beneficial for the studied stocking rate and climate conditions.