Managing Livestock Grazing Distribution on South Dakota Rangelands

Improving grazing distribution in pastures and on rangeland in South Dakota can increase utilization of the forage resource and animal performance. Managing proper grazing distribution is just one aspect of an overall grazing management plan

Managing Smooth Bromegrass Pastures in South Dakota

Smooth bromegrass is a cool-season grass introduced into the U.S. in the latter part of the 19th century. Because of its highly developed root system, smooth bromegrass is resistant to wide temperature extremes and extensive drought. This resistance has allowed it to become a dominant species in pastures and on native rangeland in eastern and central South Dakota. It is a leafy and sod-forming perennial that spreads aggressively through seeds and rhizomes and establishes well on deep, well-drained silt, clay loam, or sandy soils (Fig 1)

Spring Clipping, Fire, and Simulated Increased Atmospheric Nitrogen Deposition Effects on Tallgrass Prairie Vegetation

Defoliation aimed at introduced cool-season grasses, which uses similar resources of native grasses, could substantially reduce their competitiveness and improve the quality of the northern tallgrass prairie. The objective was to evaluate the use of early season clipping and fire in conjunction with simulated increased levels of atmospheric nitrogen deposition on foliar canopy cover of tallgrass prairie vegetation. This study was conducted from 2009 to 2012 at two locations in eastern South Dakota. Small plots arranged in a split-plot treatment design were randomized in four complete blocks on a warm-season grass interseeded and a native prairie site in east-central South Dakota. The whole plot consisted of seven treatments: annual clip, biennial clip, triennial clip, annual fire, biennial fire, triennial fire, and undefoliated control. The clip plots consisted of weekly clipping in May to simulate heavy grazing. Fire was applied in late April or early May. The subplot consisted of nitrogen applied at 0 or 15 kg N · ha−1 in early June. All treatments were initially applied in 2009. Biennial and triennial treatments were reapplied in 2011 and 2012, respectively. Canopy cover of species/major plant functional groups was estimated in late August/early September. Annual clipping was just as effective as annual fire in increasing native warm-season grass and decreasing introduced cool-season grass cover. Annual defoliation resulted in greater native warm-season grass cover, less introduced cool-season grass cover, and less native cool-season grass cover than biennial or triennial defoliation applications. Low levels of nitrogen did not affect native warm-season grass or introduced cool-season cover for any of the defoliation treatments, but it increased introduced cool-season grass cover in the undefoliated control at the native prairie site. This study supports the hypothesis that appropriately applied management results in consistent desired outcomes regardless of increased simulated atmospheric nitrogen depositions

Persistence Wins: Long-Term Agricultural Conservation Outreach Pays Off

This article discusses the lesson learned from an Extension, state, and federal agency coordinated water quality project that was formally started in 1995. In the project, educational programing was provided, high risk areas were identified, and BMPs were implemented on these areas. The net result of BMP implementation was a 38% improvement in South Dakota Bad River water quality. This improvement was attributed to Extension and others providing leadership on: 1) the development of local learning communities and 2) identification and implementing BMP\u27s in high risk areas. This work demonstrates that Extension can make a difference

Ecology and management of Sandhills rangeland: Fall grazing of uplands and ecosystem dynamics of subirrigated meadows

An experiment was conducted to determine the effects of 5 consecutive years of summer grazing date and fall stocking rate on vegetation and dietary crude protein content of cows grazing rangeland in the Nebraska Sandhills. Paddocks were grazed at a summer stocking rate of 0.5 AUM ha-1 in June or July, or deferred from summer grazing. The paddocks were then grazed in the fall at stocking rates of 0.0 AUM ha-1, 1.0 AUM ha-l, 2.0 AUM ha-1, or 3 AUM ha-l. Summer grazing date does not appear to consistently affect herbage production, fall standing crop, herbage disappearance, or fall diet quality. Fall stocking rate reduced cool-season graminoid production although this effect appears to require 3 to 5 consecutive years of fall grazing. Disappearance increased with increasing fall stocking rate by year 5 of the experiment. Crude protein content of fall diets declines with increasing fall grazing pressure but does not appear to be dictated by summer grazing date. Animal intake of fall herbage appeared to be restricted to some degree by low quality forage. In the second experiment, botanical composition, root mass-density, and carbon/nitrogen budgets were compared between cool-season and warm-season subirrigated meadows in the Sandhills. Vegetation yields and composition were sampled at each of 5 cool-season and 5 warm-season meadows. The A and C horizons of one-half of the soil cores (n=150) extracted from each meadow were analyzed for total C and N content. Stable C isotope analysis was conducted on soil sub-samples from the A and C horizon to determine the origin of soil C. The remaining soil cores were segmented into 10-cm increments. Root material was extracted from each 10-cm increment to estimate root mass-density distribution. Cool-season meadows had 12% greater (P\u3c0.1) herbage yields than warm-season meadows. Root-mass density was 30% greater (P\u3c0.1) in warm-season meadows than in cool-season meadows. Total C and N content was 43% greater (P\u3c0.1) in the A horizon of cool-season meadows, but was 40% greater (P\u3c0.1) in the C horizon of warm-season meadows. Although cool-season meadows had more soil C, much of the C in cool-season meadows appeared to be recalcitrant C from historic warm-season vegetation

GRAZING MANAGEMENT: Summer Grazing Strategies following Early-Season Grazing of Big Bluestem

Big bluestem (Andropogon gerardii Vitman) has a rapid growth phase that begins in early to mid-June in eastern Nebraska. During this rapid growth phase, rate of biomass accumulation exceeds intake rate of grazing livestock, resulting in low levels of harvest efficiency. To delay the rapid growth phase, big bluestem pasture can be grazed in mid- to late May without affecting herbage yields for the remainder of the growing season. A pasture experiment was conducted in 1999, 2000, and 2001 near Mead, NE. The objective was to determine the effect of timing and frequency of grazing big bluestem pasture, following a May grazing period, on cumulative pregrazing yields, cumulative herbage disappearance, resulting harvest efficiency, leaf/stem ratio, and stand persistence. Yield and morphological characteristics were obtained immediately before and after each grazing period, and basal cover of big bluestem was estimated annually. May grazing had no effect (P\u3c 0.1) on cumulative pregrazing yields and resulted in an increase of cumulative herbage disappearance (3638 vs. 2673 kg ha-1) and leaf/stem ratio (2.02 vs. 2.83) compared with paddocks with no May grazing. Grazing at the vegetative stage in June compared with Study Site the elongation stage resulted in an increase in cumulative pregrazing yields (10774 vs. 9510 kg ha-1), cumulative herbage disappearance (4116 vs. 3194 kg ha-1), and leaf/stem ratios (2.57 vs. 1.98). Grazing the elongation stage in June followed by a grazing period in early August is not an advisable management strategy

Comparison of Botanical Composition, Soil Carbon Content, and Root Distribution of Subirrigated Meadows in The Nebraska Sandhills

Characterizing vegetation composition, carbon/nitrogen (C/N) content of soils, and root-mass distribution is critical to understanding carbon sequestration potential of subirrigated meadows in the Nebraska Sandhills. Five subirrigated meadows dominated by cool-season (C3) graminoids and five meadows dominated by warm-season (C4) grasses were selected throughout the Nebraska Sandhills. Vegetation, soil carbon and nitrogen, and root-mass density distribution were sampled in each meadow. Meadows dominated by C3 vegetation had 12% greater (P \u3c 0.1) yields than meadows dominated by C4 vegetation. Total root-mass density was 30% greater (P \u3c 0.1) in C4-dominated meadows than C3-dominated meadows. Total carbon and nitrogen content was 65% and 53% greater (P \u3c 0.1), respectively, in the A horizon of C3-dominated meadows, but was 43% and 52% greater (P \u3c 0.1), respectively, in the C horizon of C4-dominated meadows. Although meadows dominated by C3 vegetation had more carbon in the soil profile, much of the carbon in C3-dominated meadows appeared to be recalcitrant C4 carbon from historic vegetation

Vegetation Production Responses to October Grazing in the Nebraska Sandhills

Understanding the long-term effect of summer grazing date and fall stocking rate on herbage production is critical to extending the grazing season in the Nebraska Sandhills. A study was conducted from 1997 to 2002 at the Gudmundsen Sandhills Laboratory located near Whitman, Nebraska, to determine the herbage production response to summer grazing date and October stocking rate on two different sites. Site 1 was dominated by warm-season grasses and site 2 was dominated by cool- season graminoids. At each site, three 0.37-ha pastures were constructed in each of four blocks before application of summer grazing treatments. Pastures in each block were grazed at 0.5 animal-unit months (AUM) ha-1 in June or July, or were deferred from summer grazing. Following summer grazing treatments, October stocking rate treatments (no grazing or 1.0, 2.0, or 3.0 AUM ha-1) were applied to subunits of each summer grazing date pasture during mid-October. Vegetation was sampled in each pasture in mid-June and mid-August and sorted by functional group to determine the effect of 5 yr of grazing treatments on herbage production and residual herbage. Herbage production was not affected by summer or October grazing treatments on the warm-season grass-dominated site. Increasing October stocking rate, however, reduced cool-season graminoid production and subsequent herbage production 25% by year 5 of the study. Residual herbage at both sites at the end of the October grazing periods explained as much as 16% to 34% of subsequent year’s herbage production. Grazing managers in the Nebraska Sandhills can extend the grazing season by lightly stocking pastures in the summer to facilitate additional fall grazing. Heavy stocking in October over several years on cool-season-, but not warm-season-, dominated sites will reduce production of cool- season graminoids on these sites.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Preventing Saltcedar (Tamarix spp.) Seedling Establishment in the Northern Prairie Pothole Region

Controlled burns and grazing are being tested to manage invasive grasses in the Prairie Pothole region of the Northern Great Plains. These practices, however, may inadvertently promote saltcedar infestations from seed by opening the vegetative canopy. Saltcedar seedling establishment was investigated in greenhouse experiments using intact soil cores from one summit and three footslope sites in eastern South Dakota. Establishment tests were conducted in soil cores collected from treatment and control plots immediately after spring fire treatment (postburn) and in cores that contained peak cool- or peak warm-season vegetation, with or without clipping (simulated grazing treatment), to simulate vegetation conditions typical of saltcedar seed-shed in northern regions. Cores were seeded with 100 saltcedar seeds and subirrigated to maintain high soil water conditions, characteristic of the environment near potholes during late spring/early summer. Seedlings were counted during the first 3 wk to estimate establishment and the height of five seedlings core−1 were measured weekly to estimate growth rates. Opening the canopy with fire or clipping increased saltcedar establishment. Cores taken immediately after fire treatment had two times more seedlings establish (38% vs. 19%) and greater average seedling growth rate (1.5 mm d−1 vs. 0.9 mm d−1) when compared with no-fire controls. Fire after seeding reduced seedling establishment to 5%, but did not affect growth rate. Saltcedar establishment in peak cool-season vegetation cores was 6% regardless of earlier fire treatment, whereas in peak warm-season vegetation, establishment ranged from 8% (no spring fire) to 17% (spring fire). If soils remain wet, invasion risk following spring fire may be greatest when warm-season grasses are flowering because this time coincides with northern saltcedar seed production. Areas adjacent to viable saltcedar seed sources should be managed to maximize canopy cover when seeds are released to limit further establishment. Fire after saltcedar seed deposition may control propagules and young seedlings