Jed O. Eberly

Diversifying small‐grain production systems is encouraged in the US northern Great Plains and similar semiarid regions. Our objective was to determine how crop sequence affected small‐grain crop disease, grain yield, and soil biology in shallow dryland soils of central Montana. Barley ( Hordeum vulgare L.), canola ( Brassica napus L.), field pea ( Pisum sativum L.), lentil ( Lens culinaris Medik.), and hard red spring wheat ( Triticum aestivum L. emend. Thell.) were established in a strip plot design in 2018 and 2019 so that there were 25 different 2‐year sequences in the second year. The 2‐year sequences were repeated in the same strips in 2020–2021 and 2022–2023. Crop disease was minimal and unaffected by previous crop ( p = 0.30). Interactions between year and current crop as well as year and previous crop were detected for grain yield ( p < 0.05), but not between current and previous crop ( p = 0.96) or year, current crop, and previous crop ( p = 0.95). Barley yields were comparable to or greater than those produced by other crops in 4 years, field pea and spring wheat in 3 years, and lentil in 2 years. Previous crop did not affect yield except in a very dry year when crops yielded less following low‐residue field pea than high‐residue cereal crops. Bacterial and fungal diversity were impacted by sequence but limited to genera that comprised <1% of the soil microbial community. Our results suggest that benefits may not occur 4 years after establishing cereal–pulse and cereal–oilseed sequences on shallow dryland soils.

: Soil microorganisms are crucial for plant survival and productivity, but factors governing rhizosphere recruitment across diverse regions remain unclear. This study investigated the rhizosphere microbiome of barley, using elite cultivars across seven location-year trials to evaluate the effects of environmental factors and crop genotype on bacterial and fungal community composition. Three locations were in the US northern Great Plains, and Hawai’i was used as a contrasting environment. A greenhouse reciprocal transplant study determined the relative contributions of soil physicochemical factors and soil inoculum to rhizosphere community structure. Using 16S and ITS2 amplicon sequencing, the study characterized bacterial and fungal microbiomes and assessed the contribution of environment, soil chemistry, and barley genetics to microbial community assembly. In locations within the adapted range of barley, Actinobacteriota was the dominant phylum, while Proteobacteria was dominant in Hawai’i. Variance partitioning showed that 73% of bacterial and 80% of fungal genera were associated with location-year effects while 53% of bacterial and 36% of fungal genera were responsive to soil factors. Enrichment analysis found 21.6% of bacterial and 51.4% of fungal ASVs were unique to specific barley genetic subpopulations. Results from the reciprocal transplant study validated field observations by demonstrating that 20.7% of the variation in community structure was explained by soil while 18.2% was explained by inoculum source. These findings demonstrate that environmental variation is the dominant constraint on rhizosphere community composition but within these constraints, barley genotype drives recruitment of distinct bacterial and fungal taxa. Importance: These findings underscore the complex interplay between plant genotype, environment, and microbial community assembly, providing insights into how barley recruits distinct microbial communities in the rhizosphere across different environments. These insights have the potential to be leveraged for management and plant breeding strategies to optimize plant-microbe interactions for enhancing agricultural sustainability.

Introduction: Limited rainfall in semi-arid regions can lead to forage deficiencies necessitating protein supplementation for beef cattle diets. The objective of this study was to investigate the effects of protein supplement type and delivery method on rumen bacterial communities in beef cattle. We hypothesized that rumen degradable protein (RDP) supplement would enrich for proteolytic and fiber-degrading microorganisms, and the effects of protein supplementation would be modulated by the delivery method due to differences in intake rate, which would lead to greater ammonia accumulation in self-fed animals. Methods: Treatments were RDP or rumen undegradable protein (RUP) delivered via hand-feeding (HF) or selffeeding (SF). Rumen samples were collected at 0 (pre) and 8 h post-feeding for 16S rRNA gene sequencing for bacterial community analysis. Results and discussion: No differences in alpha diversity were observed between protein supplements, but hand-fed animals had 40% greater alpha diversity when fed the RDP supplement compared to SF, and a protein × delivery method interaction ( p = 0.02) was also observed. The genus Blautia had 2-fold greater relative abundance ( p < 0.05) in RUP-supplemented animals and was positively correlated with butyric acid concentration (Pearson’s r = 0.6, p < 0.01), while Streptococcus lutetiensis had 2-fold greater relative abundance ( p < 0.05) in RDP-supplemented animals. Co-occurrence network analysis revealed greater connectivity in RDP-supplemented communities, with Prevotellaceae comprising 33% of keystone taxa compared with a single representative in RUP communities. Results demonstrated an interaction between supplement type and delivery method, indicating that how supplements are provided (controlled vs. ad libitum ) can significantly alter microbial outcomes. These results have important implications for beef cattle production in semi-arid regions where forage quality is often limiting. Producers should consider RDP supplementation during periods of poor forage quality to optimize rumen microbiota function and enhance forage utilization efficiency. However, the delivery method must be carefully managed, as unrestricted access to RDP supplements can reduce bacterial community diversity.

Annual crop yield losses due to plant diseases and weeds can be substantial. In the northern Great Plains, Bromus tectorum (L.) (also known as cheatgrass or downy brome) and Fusarium pseudograminearum (causing crown rot) form a multi-trophic pest complex threatening wheat production sustainability. This study assessed the impact of these pests on the wheat rhizosphere bacterial community. Field trials were conducted over four site-years in plots inoculated with F. pseudograminearum using a randomized split-plot design with two seeding and nitrogen fertilizer rates and B. tectorum presence/absence. A seed fungicide treatment was also used to evaluate its effect on F. pseudograminearum abundance. Rhizosphere bacterial communities were analyzed using full-length 16 S rRNA sequencing on the Oxford Nanopore platform, followed by diversity analysis, structural equation modeling (SEM), and co-occurrence network analysis. Alpha and beta diversity were significantly different between location-years. The SEM results showed a negative relationship (β = -0.180, p = 0.002) between F. pseudograminearum presence and rhizosphere bacterial community alpha and beta diversity. Effects of B. tectorum presence, seeding rate, nitrogen fertilizer, and fungicide treatment were not significant. Correlation analysis identified specific bacterial taxa responsive to F. pseudograminearum presence, including putatively beneficial species belonging to the genera Massilia, Bacillus, and Neobacillus, which were positively correlated with pathogen presence, suggesting a stress response mechanism. Network analysis revealed that F. pseudograminearum presence reduced network cohesion, and connectivity measures compared to treatments with lower pathogen load. These findings demonstrate that fungal pathogen presence can impact rhizosphere bacterial networks even when overall diversity metrics show minimal changes, highlighting the importance of network-based approaches in understanding plant-microbe-pathogen interactions in agricultural systems.

The analysis of unoccupied aerial system (UAS) imagery remains a bottleneck to obtaining actionable data due to its complexity and required specialized skill set. We introduce a workflow designed to balance usability and flexibility in processing UAS imagery using QGIS, an open‐source geographic information system software. The workflow consists of four sequential steps: semi‐automated plant classification, user‐corrected plot delineation, spectral index calculation, and data extraction. We tested this workflow on barley UAS image data, collected over 12 flights throughout the growing season. As a proof‐of‐concept, multiple red‐green‐blue (RGB) indices were calculated to test for relationships to ground‐sampled data and exemplify applications of spectral analysis. Our results indicate a strong correlation between the visible atmospheric resistant index and ground truth data, particularly when integrated over multiple flights. This open‐source workflow provides a lower barrier‐to‐entry solution for researchers and producers, facilitating the broader adoption of UAS technology in agriculture. By automating routine tasks while allowing user intervention for critical adjustments, this approach enhances the efficiency of agricultural data analysis.

Creeping perennial weeds are difficult to manage on organic farms in semi-arid regions of the northern Great Plains. Integrated weed management practices that combine biological, cultural, and mechanical controls can improve management of these weeds, but little is known about the soil microbial response to these practices. Our work investigated the soil microbiome response to contrasting, 4-year crop sequences with standard and reduced tillage. The crop sequences included a range of crop competition phases from high (three years of alfalfa, Medicago sativa L.) to low (two years of continuous fallow), within the longer 4-year period, with intermediate levels of crop competition between those two extremes. Soil samples were collected, and bacterial 16S and fungal ITS amplicon sequencing was performed. Differences in alpha diversity were not significant (p > 0.05) between tillage methods. Across all six locations, bacterial alpha diversity was negatively correlated with soil organic matter (R = -0.37, p < 0.001) while fungal alpha diversity was positively correlated (R = 0.17, p = 0.043). Bacterial community composition was not affected by crop sequence or tillage treatment. Fungal community composition was affected by crop sequence (p = 0.00163) and tillage (p = 0.02). The fungal genera Neosetophoma, Boeremia, and Paraphoma were 10 – 35-fold more abundant in continuous alfalfa compared to the mean abundance in the other crop sequences. Reduced tillage led to a 40% reduction in the fungal genus Fusarium, which contains many plant pathogen species. These results suggest that diversified crop sequences and altered tillage methods have minimal impact on bacterial communities, but fungal communities are sensitive to these management changes.

‘MT Blackbeard’ (Reg. no. CV‐1212, PI 703025) and ‘MT Raska’ (Reg. no. CV‐1213, PI 703026) are spring durum wheats ( Triticum turgidum L. ssp. durum ) developed by the Montana Agricultural Experiment Station and released in 2022. MT Blackbeard was bred using a four‐parent cross followed by single seed descent and was selected for high yield under rainfed conditions across Montana, low grain cadmium accumulation, large seed size, high gluten strength, and resistance to the most common races of the stem rust ( Puccinia graminis f. sp. tritici ) and leaf spot pathogens in Montana. MT Raska was also bred using a four‐parent cross followed by single seed descent and was selected for high yield under rainfed conditions across Montana, semi‐dwarf plant height, exceptional test weight, semolina color retention, and resistance to the most common races of the stem rust and leaf spot pathogens in Montana. Both lines yield well in the North Central and Eastern regions of Montana, where most Montana durum is produced and are intended for pasta production. MT Blackbeard is approximately 72.7 cm tall, similar to the commonly produced line ‘ND Riveland’, has signature black awns, and flowers 1 day later than ND Riveland. MT Raska is approximately 56.2‐cm tall, significantly shorter than ND Riveland, and flowers approximately 4 days earlier than ND Riveland.

Biological nitrogen fixation by rhizobia bacteria plays a pivotal role in sustainable agriculture by converting atmospheric nitrogen into a form that plants can assimilate, thereby reducing the need for synthetic fertilizers. This process can be dramatically reduced by various abiotic stressors. Native rhizobia strains, which are naturally occurring, may be better adapted to the local soil and climatic conditions, making them more resilient to stress factors such as drought, salinity, temperature extremes, and pH variations compared to commercial strains that may have been developed in and for different environments. This study aimed to compare the efficacy of native rhizobia species with a commercial inoculant and uninoculated controls in maintaining nitrogen fixation under induced stress by delayed planting in field peas over two growing seasons (2021 and 2022) in central South Dakota. Our findings indicate that native rhizobia, while not outperforming the commercial inoculant, demonstrated competitive nitrogen fixation capacities. Overall, total nitrogen fixation was not statistically different between a commercial inoculant and native rhizobia formulations. Planting date emerged as a significant factor influencing nitrogen fixation, with later planting substantially reducing overall effectiveness. These results highlight the potential of native rhizobia as an alternative to commercial inoculants and underscore the need for increased screening throughput and improved methods to assess rhizobia efficacy and nodule competition in field settings.