Production characteristics of the mixed prairie: constraints and potential

1993 ◽  
Vol 73 (4) ◽  
pp. 765-778 ◽  
Author(s):  
W. D. Willms ◽  
P. G. Jefferson

The mixed prairie represents the most arid region of the Northern Great Plains in Canada. Approximately 6.5 M ha of the original total of 24 M ha have retained their native character. The native prairie supports about 5.3 M animal–unit–months or about 15% of all beef cattle present on the Canadian prairies. A large portion of the area is dominated by either needle-and-thread (Stipa comata Trin. + Rupr.) or western wheatgrass (Agropyron smithii Rydb.), both cool season grasses, and associated with blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Steud.] a warm season grass. These species define the major plant communities of the mixed prairie and determine their production potential. However, their production is limited by available water during the growing season and by soil nutrients; factors which also influence their species composition. Grazing imposes a significant impact on the grasslands by altering the water and nutrient cycles, through defoliation and reduced plant litter, and eventually by affecting the species composition. Removing litter may reduce forage production by up to 60% and repeated defoliation will favour the more drought tolerant but less productive species. Forage production may be increased by seeding introduced species, which have a greater shoot to root ratio than native grasses, or with fertilizer application. Livestock production may be increased with the use of grazing systems. However, the benefits of each practice on the mixed prairie must be assessed in terms of their cost, their impact on the environment, and the reduced or lost value for other users. Key words: Biomass, above-ground, below-ground, water-use efficiency, reseeding, soil fertility, grazing efficiency


2005 ◽  
Vol 137 (4) ◽  
pp. 497-500 ◽  
Author(s):  
Tuilo B. Macedo ◽  
Paula A. Macedo ◽  
Robert K.D. Peterson ◽  
David K. Weaver ◽  
Wendell L. Morrill

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is an insect pest in dryland wheat cropping systems in the southern Canadian Prairies and the northern Great Plains of the United States (Morrill 1997). Yield losses caused by C. cinctus are due to reduced head weight (Holmes 1977; Morrill et al. 1992) and lodging, which decreases harvest efficiency. Estimates of yield losses in Montana alone are about US$25 million per year.



2018 ◽  
Vol 98 (6) ◽  
pp. 1234-1244
Author(s):  
Nityananda Khanal ◽  
Michael P. Schellenberg ◽  
Bill Biligetu

White prairie clover [Dalea candida (Michx.) Willd.] is native to the dry prairies and hillsides of the Northern Great Plains. A study was initiated in 2012 with six white prairie clover populations collected from the Canadian Prairies. Plant growth characteristics, forage biomass, seed yield, and forage nutritive values were evaluated using a randomized complete block design in a field near Swift Current, SK. Three populations from Argyle, Carlowrie, and Big Grass Marsh (NCP588) in Manitoba displayed erect-type growth while those from Douglas Provincial Park and Stewart Valley in Saskatchewan and Writing on Stone Provincial Park in Alberta exhibited prostrate growth. The populations did not differ for mean biomass yield (79–104 g plant−1, p = 0.54) and mean seed yield (6.6–9.1 g plant−1, p = 0.69); however, they differed for bloom stage nutritional parameters such as acid detergent fibre (25%–30%, p = 0.04), neutral detergent fibre (34%–41%, p < 0.01), crude proteins (15%–18%, p < 0.01), phosphorus (0.24%–0.29%, p = 0.02), and iron content (144–360 ppm, p = 0.01). To our knowledge, this is the first report of comparative phenotypic, nutritional, and propagation study of native white prairie clover populations of Canada. The constraints and opportunities for successful domestication of white prairie clover as a forage crop are discussed.



2019 ◽  
Vol 34 (4) ◽  
pp. 805-831 ◽  
Author(s):  
Jingyu Wang ◽  
Xiquan Dong ◽  
Aaron Kennedy ◽  
Brooke Hagenhoff ◽  
Baike Xi

Abstract A competitive neural network known as the self-organizing map (SOM) is used to objectively identify synoptic patterns in the North American Regional Reanalysis (NARR) for warm-season (April–September) precipitation events over the Southern and Northern Great Plains (SGP/NGP) from 2007 to 2014. Classifications for both regions demonstrate contrast in dominant synoptic patterns ranging from extratropical cyclones to subtropical ridges, all of which have preferred months of occurrence. Precipitation from deterministic Weather Research and Forecasting (WRF) Model simulations run by the National Severe Storms Laboratory (NSSL) are evaluated against National Centers for Environmental Prediction (NCEP) Stage IV observations. The SGP features larger observed precipitation amount, intensity, and coverage, as well as better model performance than the NGP. Both regions’ simulated convective rain intensity and coverage have good agreement with observations, whereas the stratiform rain (SR) is more problematic with weaker intensity and larger coverage. Further evaluation based on SOM regimes shows that WRF bias varies with the type of meteorological forcing, which can be traced to differences in the diurnal cycle and properties of stratiform and convective rain. The higher performance scores are generally associated with the extratropical cyclone condition than the subtropical ridge. Of the six SOM classes over both regions, the largest precipitation oversimulation is found for SR dominated classes, whereas a nocturnal negative precipitation bias exists for classes featuring upscale growth of convection.



1999 ◽  
Vol 79 (3) ◽  
pp. 335-341 ◽  
Author(s):  
M. P. Schellenberg ◽  
N.W. Holt ◽  
J. Waddington

Conventional belief is that mixed prairie range is harmed by early spring use but not by moderate grazing after the grasses have flowered. Our hypothesis was that mixed prairie range may be grazed for a limited period in the growing season providing rest is allowed for the remainder of the year. This 6-yr test was established on a rolling site of range pasture, which contained, by area, 65% upland mixed prairie, 5% lowland bluegrass (Poa spp.) and 30% crested wheatgrass (Agropyron cristatum). The species mix is commonly found in southern Canadian prairies. The mixed prairie grasses were needle and thread (Stipa comata), northern wheatgrass (Elymus lanceolatus), western wheatgrass (Pascopyrum smithii) and blue grama (Bouteloua gracilis). Each pasture was 1.6 ha and was grazed with yearling beef cattle once a year beginning mid-May; the end of June; mid-August or late September. Forage yields in grazing-exclusion cages averaged 580, 2960, and 1370 kg ha−1 for the mixed prairie, lowland grasses, and crested wheatgrass, respectively. The date of grazing in the previous year did not affect current-year maximum forage yield. The main determinant of maximum forage yield was a combination of spring soil moisture plus April to June precipitation. Available forage for grazing, on average, doubled from mid-May until the end of June for the three forage types. There were year-by-grazing date interactions, which were related to distribution of precipitation. Mixed prairie was the preferred forage at the last two grazing dates. Forage digestibility, N and P content were highest during the May and June grazing period and declined thereafter. Average daily gain of the steers decreased from 0.9 kg d−1 in May and late June to 0.2 kg d−1 by late September. Annual carrying capacity (in standard animal units) was 40 d ha−1 in May and averaged 55 d ha−1 for the other dates, which were not different. Grazing mixed prairie did not have a negative effect on the yield of native grasses when used for only one short period per year. Delayed use from mid May to end of June increased available forage and carrying capacity. Key words: Mixed grass prairie, crested wheatgrass, grazing, weather effects



2015 ◽  
Vol 8 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Erin K. Espeland ◽  
Robert Kilian

AbstractAnnual bromes (downy brome and Japanese brome) have been shown to decrease perennial grass forage production and alter ecosystem functions in northern Great Plains rangelands. Large-scale chemical control might be a method for increasing rangeland forage production. Although fall application has been shown to be the most effective and least likely to impact co-occurring native species, spring germination of downy brome may reduce the efficacy of fall-only herbicide application. We assessed the impact of a low glyphosate dose rate (210 g ha−1) applied to rangelands in fall or in fall and spring on nontarget species and on annual brome abundance at two sites in eastern Montana over 2 yr. We tested the following hypotheses: (1) nontarget effects are greater with spring herbicide application, (2) fall and spring herbicide application are necessary for effective downy brome control, and (3) fall herbicide application is sufficient to control Japanese brome. Few nontarget effects occurred; two dicotyledonous species exhibited small increases in response to herbicide. We found that that a single fall application reduced downy brome cover and seed bank density, but after the second fall application in the following year, downy brome did not continue to show a response to herbicide. After 2 yr of fall herbicide application, Japanese brome had denser seed banks in plots where herbicide had been applied. Blanket glyphosate application on rangelands is an unreliable method for controlling annual brome invasions in the northern Great Plains.



2013 ◽  
Vol 93 (5) ◽  
pp. 793-798 ◽  
Author(s):  
M. P. Schellenberg ◽  
B. Biligetu ◽  
Y. Wei

Schellenberg, M. P., Biligetu, B. and Wei, Y. 2013. Predicting seed germination of slender wheatgrass [Elymus trachycaulus (Link) Gould subsp. trachycaulus] using thermal and hydro time models. Can. J. Plant Sci. 93: 793–798. Slender wheatgrass [Elymus trachycaulus (Link) Gould subsp. trachycaulus] is a native caespitose grass used for forage production and reclamation. The objective of this study was to quantify seed germination requirements of slender wheatgrass using thermal and hydro time models. Slender wheatgrass, San Luis, had a base temperature (Tb) of 9.48°C, and required 946.8°C h to reach 50% of seed germination. Seed germination of San Lius occurred at a temperature range of 10–30°C, with the highest germination rate being achieved at 20°C, and the highest final germination percentage being achieved at 25°C. At 20 and 25°C, San Luis had a hydro time constant of 61 MPa h, and a median base water potential of approximately 1.0 MPa, but the germination had low uniformity in reduced water potentials. Final germination was reduced at or lower than –0.6 MPa. Compared with many other cool-season native grasses of Northern Great Plains, a relatively warm temperature would be necessary for uniform seedling establishment of this grass. In reclamation seeding, the seedling emergence could reach the highest level at a temperature of 25°C.



2014 ◽  
Vol 92 (1) ◽  
pp. 49-55 ◽  
Author(s):  
T.M. Radtke ◽  
J.R.N. Glasier ◽  
S.D. Wilson

Habitat alteration by exotic plant species can have profound effects on vertebrates, but its effects on invertebrates are less well-known. Crested wheatgrass (Agropyron cristatum (L.) Gaertn.) is a perennial grass that has been planted on >106ha of the Great Plains. We tested the hypothesis that invertebrate communities (especially ants) differed between native grasslands and A. cristatum stands, using pitfall traps in Saskatchewan and Montana. Ant species composition differed significantly between native grasslands and A. cristatum stands, but there were no differences in total ant abundance, the abundance of functional groups, or species richness. Ant species richness was significantly greater in Montana than Saskatchewan. In Saskatchewan, bare ground was positively related to total ant abundance and the abundance of “cold-climate specialist” and “opportunist” functional groups of ants. In Montana, the cover of forbs was positively related to total ant abundance. The abundances of individual ant species were not predicted by any vegetation characteristics, except for Formica obscuripes Forel, 1886, which increased significantly with litter. The total abundance of other invertebrates was greater in native grasslands than in A. cristatum stands, although not significantly so. Within each vegetation type, variation in ant communities may depend either directly on the effects of vegetation species composition, or indirectly via the effect of vegetation on other factors such as temperature. The results suggest that ant community composition was influenced more by variation within grasslands and between locations than by differences between native and exotic grasslands.



2013 ◽  
Vol 13 (12) ◽  
pp. 32269-32289
Author(s):  
T. Logan ◽  
B. Xi ◽  
X. Dong

Abstract. Biomass burning aerosols can have a large impact on atmospheric processes as well as human health. During the 2012 warm season, a large outbreak of wildfires originating from the intermountain and Pacific states provided many opportunities to observe the physical and chemical properties of biomass smoke aerosols. Six biomass burning smoke plumes (26 June–15 September) have been observed by the newly installed Grand Forks, North Dakota, AERONET site (47.91° N, 97.32° W) and are selected for this study. To identify the source regions, HYSPLIT backward trajectory model data and satellite imagery are used to track these events. The volume size distribution and spectral aerosol optical depth (AOD) dependence showed the relative influences of fine and coarse mode particles. Case II (4 July) had the strongest fine mode influence as evidenced by a strong spectral AOD dependence while Case VI (15 September) had the strongest coarse mode influence with the weakest spectral dependence. The spectral dependences of absorption aerosol optical depth (AAOD) and single scattering co-albedo (ωoabs) illustrated the varying absorption of the smoke plumes by inferring the relative contributions of strongly and weakly absorbing carbonaceous species. More specifically, the AAOD parameter is primarily influenced by aerosol particle size while ωoabs is more dependent on aerosol composition. The AAOD spectral dependences for Cases I (26 June), III (31 July), and VI were weaker than those from Cases II, IV (28 August), and V (30 August). However, the spectral ωoabs dependences were different in that the smoke particles in Cases III and VI had the strongest absorption while Cases I, II, IV, and V had moderate to weakly absorbing particles. In addition, a weak correlation was found between plume transport time and particle absorption where strongly absorbing carbon was converted to weakly absorbing carbon.



2020 ◽  
Vol 29 (1) ◽  
pp. 67-69
Author(s):  
David H. Branson

Livestock grazing frequently affects grasshopper populations, but no prior studies have simultaneously examined a wide range of moderate intensity livestock grazing treatments in the Northern Great Plains. Grasshopper densities varied significantly between years, but five moderate grazing treatments, including both rotational and continuous grazing treatments, did not differentially affect grasshopper densities or species composition. Grasshopper populations appear resilient to different types of moderate grazing at this Northern Great Plains mixed-grass prairie site.



2021 ◽  
Author(s):  
Craig R. Ferguson

&lt;p&gt;In the semi-arid U.S. Great Plains, nocturnal southerly low-level jets (LLJs) serve critical roles as conveyors of remotely-sourced (i.e., Gulf of Mexico) water vapor and agents of atmospheric instability in the warm-season. &amp;#160;Defined by a diurnally oscillating wind maximum between 0&amp;#8211;3 km above the surface, LLJs have been studied by meteorologists for over 60-years due to their role in severe weather outbreaks. It is only within the past decade that a subset of LLJs with especially high vertically integrated water vapor transport, termed atmospheric rivers, have drawn the attention of hydrologists.&lt;/p&gt;&lt;p&gt;In this study, changes in LLJ frequency and structure over the period from 1901&amp;#8211;2010 are quantified using ECMWF&amp;#8217;s Coupled Reanalysis of the Twentieth Century (CERA-20C). A new objective dynamical LLJ classification dataset is used to separately quantify changes in the two predominant LLJ types: synoptically coupled and uncoupled. The findings reveal that both the frequency of Great Plains LLJs and their associated precipitation have decreased significantly over the 20th century. Decreases in LLJ associated precipitation range between 10&amp;#8211;14% of total present day May&amp;#8211;September precipitation. The largest differences observed are attributable to uncoupled jet frequency and structural changes during July and August over the central and northern Great Plains. Overall, the results indicate the contribution of LLJs to the region&amp;#8217;s water budget has diminished.&lt;/p&gt;



Sign in / Sign up

Export Citation Format

Share Document