Early‐season grazing of native grasses offers potential profitable benefit

Abstract

A grazing trial was conducted in Mississippi during 2016 and 2017 to compare pasture, animal, and economic performance of three perennial, warm-season grass systems. Grass treatments included: (i) Argentine bahiagrass (Paspalum notatum Fluegge; BAH); (ii) KY Ecotype big bluestem (Andropogon gerardii Vitman; BBS); and (iii), KY Ecotype indiangrass [Sorghastrum nutans (L.) Nash], big bluestem and little bluestem [Schizachyrium scoparium (Michx.) Nash; MIX]. Paddocks were continuously stocked using weaned beef (Bos taurus) steers across three grazing intervals (I, II, and III) during late spring and summer. Pasture measurements included forage mass (FM) and nutritive value. Greatest FM was observed during grazing interval II in 2016 (931.70 kg ha -1 ). Nutritive values declined as the season progressed. The BAH had greater CP and TDN, and lower ADF and NDF concentrations than BBS and MIX in 2016. Differences were not as discernable in 2017. Greatest ADG were observed for BBS interval I in 2017 (1.34 kg d -1 ), MIX interval I 2017 (1.21 kg d -1 ), and BBS interval I 2016 (1.19 kg d -1 ). Beef yield per hectare (GAIN) was greatest for interval I across both years (464.78 kg ha-1). By species, GAIN was greatest for BBS in interval I (451.32 kg ha -1 ). For economic analysis, BBS had the lowest total annual pasture cost (US$142.65 ha -1 ), and had the greatest NET returns for 2016 ($268.96 ha -1 ) and 2017 ($249.98 ha -1 ). Implementing native warm-season grasses (NWSG) in stocker cattle systems for early-season grazing can be productive in Mississippi.

Forage production and persistence characteristics of grazed native warm‐season grass mixtures with or without nitrogen fertilizer

“…CP concentration and IVTD were less than values reported for big bluestem, little bluestem, and indiangrass mixtures under clipping studies or grazing evaluations by 2-4 percentage points (Backus et al, 2017;Brazil et al, 2020;Rushing et al, 2019Rushing et al, , 2020. Differences in forage nutritive value responses among these studies and the present trial may be due to relative canopy height and stage of maturity of NWSG during the first 30 days of defoliation management.…”

“…NWSG mixtures used in the present study also supported a 30% greater animal stocking density and AUE during the first 30 days of the grazing season than the zero‐N‐input strategy. Rushing et al (2020) reported similar initial stocking densities for the first 28 days of a stocker cattle grazing trial for big bluestem, little bluestem, and indiangrass pastures fertilized at a rate of 56 kg N ha −1 in Mississippi. Pastures in their evaluation were initially stocked at a rate of 1245 and 953 kg of animal BW per hectare in Year 1 and Year 2 of the study, respectively.…”

“…The response of NWSGs in monoculture or mixtures to N fertilization is well reported in the literature under clipping, bioenergy, or hay production systems (Angima et al, 2009; Duran et al, 2016; Lowe et al, 2015; Popp et al, 2018; Waramit et al, 2011, 2012), with generally increased forage mass observed with seasonal N application rates of up to 168 kg N ha −1 . Forage production responses of NWSG to N fertilizer application rates under grazing are more limited (B. Anderson et al, 1988; Berg, 1995; Gillen & Berg, 1998), especially in NWSG mixed species swards (Backus et al, 2017; Brazil et al, 2020; Rushing et al, 2020). Backus et al (2017) evaluated NWSG monocultures or mixtures of big bluestem and indiangrass under continuous stocking using a similar N fertilization strategy as in the present trial with an annual spring application of 67 kg N ha −1 .…”

“…Pastures in their evaluation were initially stocked at a rate of 1245 and 953 kg of animal BW per hectare in Year 1 and Year 2 of the study, respectively. Whereas early‐season forage growth of NWSG mixtures may initially support greater stocking densities (Brazil et al, 2020), adjustments to lower stocking densities on NWSG by mid‐to‐late season have been reported in the literature and coincide with the slower growth rate of NWSG as the season progresses (Backus et al, 2017; Brazil et al, 2020; Rushing et al, 2020). Nitrogen fertilization at rates used in the present study may support greater initial stocking, but adjustments in stocking management should be made during the subsequent months of the growing season to reduce grazing pressure and the potential for overgrazing (Backus et al, 2017; Brazil et al, 2020).…”

“…Forage production responses of NWSG to N fertilizer application rates under grazing are more limited (B. Anderson et al, 1988;Berg, 1995;Gillen & Berg, 1998), especially in NWSG mixed species swards (Backus et al, 2017;Brazil et al, 2020;Rushing et al, 2020). Backus et al (2017) evaluated NWSG monocultures or mixtures of big bluestem and indiangrass under continuous stocking using a similar N fertilization strategy as in the present trial with an annual spring application of 67 kg N ha −1 .…”