Planting grass-legume mixtures may be a good option to improve soil health in addition to increased forage productivity, improved forage nutritive value, and net farm profit in a hay production system. A field experiment was conducted from 2011 to 2014 at Lingle, Wyoming to evaluate soil microbial biomass under different seeding proportions of two forage grasses (meadow bromegrass, Bromus biebersteinii Roem. & Schult.; and orchardgrass, Dactylis glomerata L.) and one legume (alfalfa, Medicago sativa L.). Nine treatments included monoculture grass, monoculture legume, one grass and one legume mixture, two grasses and one legume mixture, and a control (not seeded with grass or legume). Monoculture grass received either no nitrogen (N) or N fertilizer (150 kg N ha⁻¹ year⁻¹ as urea) whereas monoculture legume, grass-legume mixtures, and control plots received no N fertilizer. The study was laid out as a randomized complete block design with three replications. The plots were harvested 3–4 times each year after the establishment year. Soil samples were collected and analyzed for microbial biomass using phospholipid fatty acid (PLFA) analysis at the end of May in 2013 and 2014. Soil samples were also analyzed for mineralizable carbon (C) and N in 2013 and 2014. The total above-ground plant biomass was higher in 50–50% mixture of grass and alfalfa than monoculture alfalfa and monoculture grass (with and without N fertilizer) during the entire study period. The application of N fertilizer to the grass hay production system had little effect on improving mineralizable soil C, N, and soil microbial biomass. However, grass-legume mixture without N fertilizer had great effect on improvement of mineralizable soil C and N, and total, bacterial, and actinomycetes microbial biomass in soil. The 50–50% mixture of grass and alfalfa performed consistently well and can be considered to use in Wyoming conditions for improving soil health and forage productivity.

Wheat (Triticum spp.) dominates dryland grain crop production in the North American Great Plains and other regions with semi‐arid steppe climates. A common practice is to alternate winter or spring wheat with a 14‐ to 21‐mo fallow period to allow for soil‐water recharge, despite economic inefficiencies and environmental degradation. Replacing fallow with non‐cereal grain and seed crops often reduces future wheat yields due to increased water stress during grain fill. The use of annual forages may not have the disadvantages associated with grain and seed crops. The objective of this review was to determine benefits and challenges of incorporating annual forages into dryland wheat systems in semi‐arid steppe climates, using the Great Plains within the United States as a model system. Results indicate that: (a) cool‐ and warm‐season, annual grass and broadleaf species can be grown for forage across the region; (b) forage production will be less risky than grain and seed crop production under predicted climate‐change scenarios; (c) grazing annual forages may offer advantages (e.g., nutrient cycling, improved soil structure, added revenue from livestock) over mechanically harvesting annual forages; (d) the lack of infrastructure and local markets impede the use of annual forages to diversify wheat‐based cropping systems in the region; and (e) limited networking among researchers hinders the advancement in knowledge on how annual forages can be used to improve dryland wheat system resilience.

In water-scarce regions, high yield and improved water use efficiency (WUE) of crops can be obtained if water and nitrogen (N) are properly applied. While water and N have been the subject of research worldwide, studies are needed to advance our understanding on the complexity of their interaction. A field experiment was conducted at the University of Wyoming Powell Research and Extension Center in 2014 and 2015 growing seasons to determine the effect of irrigation water and N on growth, dry matter (DM) yield, and WUE of silage corn (Zea mays L.) grown under on-surface drip irrigation (ODI). The experiment was laid out as a randomized complete block design in split-plot arrangement with three replications. Irrigation was the main treatment and included 100ETc (100% crop evapotranspiration), 80ETc, and 60ETc. Nitrogen was the sub-treatment and included 0, 90, 180, 270, and 360 kg N ha⁻¹ as urea-ammonium-nitrate solution Results showed that irrigation water, N, and application timing significantly affected growth and DM yield, especially at late vegetative and mid reproductive growth stages. At harvest (R4), no significant difference was observed between 180 kg N ha⁻¹ and 270 kg N ha⁻¹ on DM yield and WUE. However, significant differences of DM yield were observed between irrigation treatments, and 100ETc and 80ETc did not differ in WUE. Our findings suggest that 100ETc and 180 kg N ha⁻¹ is the best combination for high yielding corn for silage grown in a semi-arid climate under ODI.

Plant diversity is associated with resilient ecosystems. Loss of plant biodiversity triggered by anthropogenic and climatic factors jeopardizes environmental stability and sustainable forage production. The understanding of biodiversity mechanisms and functional traits of species can help to design forage production systems to buffer against perturbations. Resilience and productivity are linked to plant species characteristics and interactions that enable them to recover from adverse conditions and compensate for the loss of susceptible species. Benefits of diversified crops including enhanced carbon assimilation, nitrogen fixation, and turnover are transferred to soil microbes which in return contribute to resilience against drought and poor soil fertility. In the absence of disturbances, these mechanisms are credited for stability and climax ecosystems. Cultivated systems are more fragile because management interferes with many functions while maintaining few. Strategies that sustain an entire range of functions can increase production regardless of climatic and management factors. This has been demonstrated in binary mixtures of cool season grasses including meadow bromegrass (Bromus biebersteinii Roem. & Schult.), orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), and intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey) with alfalfa (Medicago sativa L.). Suitable combinations of perennial species and cultivars bred for compatible traits can enhance resilience and productivity in a wide range of ecosystems.