Versatile Native Grasses and a Turf-Alternative Groundcover for the Arid Southwest United States

Water use limitations offers new opportunities for utilization of low-input native grasses and groundcovers for the landscapes of southwest USA. Two field studies were conducted with eleven plant species for two years in Scottsdale and Sun City West, AZ to evaluate rate of emergence, ground surface coverage, plant height, and overall plant quality. In the laboratory, Eragrostis tef at 86% and Eragrostis intermedia at 85% were showing higher percentage of germination compared to other species. Within eight weeks, ten species exhibited an average of 81% emergence at Scottsdale while nine species showed only 58% emergence at Sun City West. Sporobolus cryptandrus grew to greater than 76 cm (30 in) in height while kurapia (Lippia nodiflora) grew to about 5 cm (2 in). The performances of the groundcover kurapia and the native grasses tested demonstrated excellent potential in the low desert southwest U.S., with low rates of water use, applying fertilizer only at planting, and less frequent mowing requirements. Lippia nodiflora, Sporobolus airoides, Bouteloua gracilis, Eragrostis intermedia, and Muhlenbergia asperifolia remained green throughout the year when mowed twice a year. Lippia nodiflora, Hilaria rigida, and Bouteloua gracilis exhibited the highest ground surface coverage and uniformity in growth. Index words: groundcover, landscape, low input, native grasses, plant species. Species used in this study: Blue grama, Bouteloua gracilis (Kunth) Lag. ex Griffiths; bufflograss, Buchloe dactyloides (Nutt.) Engelm.; plains lovegrass, Eragrostis intermedia A.S. Hitchc.; teff, Eragrostis tef (Zucc) Trotter; big galleta, Hilaria rigida (Thurb); Kurapia, Lippia nodiflora (L.) Greene; alkali muhly, Muhlenbergia asperifolia (Nees & Meyen ex Trin.) Parodi; alkali sacaton, Sporobolus airoides (Torr.) Torr.; spike dropseed, Sporobolus contractus A.S. Hitchc.; sand dropseed, Sporobolus cryptandrus (Torr.) A. Gray; and desert zinnia, Zinnia acerosa (DC.) A. Gray.

Invasive plant benefits a native plant through plant-soil feedback but remains the superior competitor

Plant soil feedback (PSF) occurs when a plant modifies soil biotic properties and those changes in turn influence plant growth, survival or reproduction. These feedback effects are not well understood as mechanisms for invasive plant species. Eragrostis lehmanniana is an invasive species that has extensively colonized the southwest US. To address how PSFs may affect E. lehmanniana invasion and native Bouteloua gracilis growth, soil inoculant from four sites of known invasion age at the Appleton-Whittell Audubon Research Ranch in Sonoita, AZ were used in a PSF greenhouse study, incorporating a replacement series design. The purpose of this research was to evaluate PSF conspecific and heterospecific effects and competition outcomes between the invasive E. lehmanniana and a native forage grass, Bouteloua gracilis. Eragrostis lehmannianaPSFs were beneficial to B. gracilis if developed in previously invaded soil. Plant-soil feedback contributed to competitive suppression of B. gracilis only in the highest ratio of E. lehmanniana to B. gracilis. Plant-soil feedback did not provide an advantage to E. lehmanniana in competitive interactions with B. gracilis at low competition levels but were advantageous to E. lehmanniana at the highest competition ratio, indicating a possible density-dependent effect. Despite being beneficial to B. gracilis under many conditions, E. lehmanniana was the superior competitor.

Draft Genome Sequence of Fusarium sp. Strain DS 682, a Novel Fungal Isolate from the Grass Rhizosphere

ABSTRACT The novel fungal strain, Fusarium sp. strain DS 682, was isolated from the rhizosphere of the perennial grass, Bouteloua gracilis, at the Konza Prairie Biological Station in Kansas. This fungal strain is common across North American grasslands and is resilient to environmental fluctuations. The draft genome is estimated to be 97.2% complete.

Vegetation Classification Exercise for the Pawnee National Grasslands, USA

Aims: Vegetation classifications are useful for a variety of management purposes as well as scientific exploration. Local classifications are common throughout the United States but only recently have been integrated into a national classification system, which is now expected for local classifications. Study Area: The Pawnee National Grasslands (PNG) in northeastern Colorado, USA, has not been classified using plot data, and is thus a gap on the baseline knowledge of the PNG plant communities that hinders impact assessment of various anthropogenic activities. Methods: Here, we use 128 plots to classify the vegetation of the PNG using a two-step process: first, classifying the PNG plots alone to characterize local uniqueness, and then employing a semi-supervised classification with an additional 64 plots from areas to the north and east of the PNG, using standard classification procedures. Results: We document on the PNG the occurrence of two Classes, three Subclasses, four Formations, five Divisions, six Macrogroups, seven Groups and eight Alliances and Associations already described in the USNVC. Conclusions: The PNG is dominated by the Bouteloua gracilis-Buchloe dactyloides Grassland Association, which we further subdivide and describe as three local subassociations. The mixed-grass concepts in the USNVC do not exist in the PNG. Taxonomic reference: Hazlett (1998). Syntaxonomic reference: USNVC (2016). Abbreviations: BLM = Bureau of Land Management; CPER = Central Plains Experimental Range; ESA = Ecological Society of America; EST = Ecological Site Type; GPS UTM = Global Positioning System Universal Transverse Mercator; NEON = National Ecological Observatory Network; PNG = Pawnee National Grasslands; USNVC = United States Vegetation Classification.

Characterizing genetically diverse blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] seed sources

The need for regionally adapted native grass seed sources for the northern Great Plains has resulted in the commercial release of a range of plant materials, including ecovars™ 1 . Ecovars™ are multisite composite populations developed to combine broad genetic diversity from a geographic region. The objective of this study was to determine whether morphological data could be used to distinguish between genetically diverse blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] seed sources through classical statistical methods. Entries included a Manitoba (MB) ecovar™, a USDA–NRCS released cultivar ‘Bad River’, and ecotypes from Wyoming and Minnesota. Vegetative and reproductive measurements and ratings were taken from a spaced-plant nursery during 2000–2001 in Carman, Manitoba, Canada. The results were analyzed using statistical techniques including: ANOVA, least significant difference, canonical discriminant analysis (CDA), and coefficients of variation. These techniques distinguished four genetically diverse seed sources from each other through CDA. As hypothesized, there was greater within-population genetic diversity for the MB ecovar™ and Wyoming and Minnesota ecotypes, compared with ‘Bad River’. Our results indicate that genetically diverse blue grama seed sources can be distinguished, based on phenotypic measurements.

Reducing Eragrostis lehmanniana populations by preparing seedbeds with unconventional tillage implements and seeding in a semiarid grassland

The invasion of Lehmann lovegrass (Eragrostis lehmanniana Nees) in rangelands of Chihuahua, Mexico, has resulted in a need for revegetation to recover lost forage productivity. Thus, new knowledge on generating alternatives to improve these invaded grasslands is of great importance. This study evaluated seedbeds prepared with unconventional tillage implements and seeded with a grass mixture to reduce the plant density of E. lehmanniana while increasing the productivity of an invaded semiarid grassland of Chihuahua. The unconventional tillage implements were: a Rangeland Harrow, which was used to prepare the Striped Harrowing and Full Harrowing seedbeds; Rangeland Rehabilitator, which was used to prepare the Deep-Stingray Subsoiler seedbed; and a Tandem-type Aerator Roller, which was used to prepare the Double-Digging Aeration seedbed. An area without tillage was left as a control. The seed mixture was composed of blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths var. Hachita] (25%); sideoats grama [Bouteloua curtipendula (Michx.) Torr. ‘6107 Kansas’] (25%); green sprangletop [Leptochloa dubia (Kunth) Nees var. Van Horn] (5%); weeping lovegrass [Eragrostis curvula (Schrad.) Nees var. Ermelo] (40%), and Columbus grass [Sorghum almum Parodi] (5%). The experiment was conducted across 4 yr, and the evaluation started at the second year. Plant density and dry matter (DM) production were evaluated per species. In the control plot, the plant density of E. lehmanniana increased approximately 180% from the 2nd to the 4th year (18 to 50 plants m−2). The use of unconventional tillage implements for seedbed preparation and the inclusion of E. curvula in the seed mixture decreased E. lehmanniana density in more than 50% of plots and increased DM production in around 100% of plots. Considering the whole experimental period, in all the prepared seedbed treatments, E. curvula had the highest establishment and DM production of all the seeded species. The native species B. gracilis, B. curtipendula, and L. dubia had poor establishment in all the prepared seedbeds.

Opposing effects of bacterial endophytes on biomass allocation of a wild donor and agricultural recipient

ABSTRACT Root endophytes are a promising tool for increasing plant growth, but it is unclear whether they perform consistently across plant hosts. We characterized the blue grama (Bouteloua gracilis) root microbiome using two sequencing methods, quantified the effects of root endophytes in the original host (blue grama) and an agricultural recipient, corn (Zea mays), under drought and well-watered conditions and examined in vitro mechanisms for plant growth promotion. 16S rRNA amplicon sequencing revealed that the blue grama root microbiome was similar across an elevation gradient, with the exception of four genera. Culturing and Sanger sequencing revealed eight unique endophytes belonging to the genera Bacillus, Lysinibacillus and Pseudomonas. All eight endophytes colonized corn roots, but had opposing effects on aboveground and belowground biomass in each plant species: they increased blue grama shoot mass by 45% (19) (mean +/− SE) while decreasing corn shoot mass by 10% (19), and increased corn root:shoot by 44% (7), while decreasing blue grama root:shoot by 17% (7). Furthermore, contrary to our expectations, endophytes had stronger effects on plant growth under well-watered conditions rather than drought conditions. Collectively, these results suggest that ecological features, including host identity, bacterial traits, climate conditions and morphological outcomes, should be carefully considered in the design and implementation of agricultural inocula.