Background: This 2-year study sought to determine the influence of N application rates following alfalfa termination on biomass production and quality of the succeeding crops of maize (Zea mays L.) and sorghum-sudangrass (Sorghum bicolor (L.) Moench × Sorghum sudanense Piper) and quantify short-term changes in soil total N (TN) under the different systems.
Methods: Treatments were two silage maize hybrids (“LG5470” and “NK0388”) and two sorghum-sudangrass hybrids (“Super sugar” and “Sweet six”) for a total of four entries and three N application rates (0, 80, and 160 kg N ha-1) in a 4 × 3 factorial in a randomized complete block design with four replications each.
Results: In the first year following termination of a 4-year alfalfa stand, no additional N was required for maize (22.9 Mg DM ha-1, SE = 1.2) and sorghum-sudangrass (19.3 Mg DM ha-1, SE = 1.2) biomass production. Total digestible nutrients (TDNs) of herbage biomass differed only in the second year, and TDNs in Year 2 were greater for the 160 kg N ha-1 rate (675.2 g kg-1 DM, SEM = 9.6) compared to the 0 kg N ha-1 rate (638.2 g kg-1 DM, SEM = 9.6).
Conclusions: The results from this study offer producers the opportunity to integrate a cropping system that will lead to significant N input cost savings, provide a reliable source of feed for the ruminant livestock industry, and promote long-term feed crop sustainability in semi-arid environments like Nevada and other similar regions worldwide.
Background: Alfalfa (Medicago sativa L.) and bermudagrass (Cynodon spp.) mixtures (ABG) can be effectively managed in Southeastern United States under cut and graze management systems. However, there is still a need to investigate the influence that bermudagrass cultivar has under these harvest management strategies (HMS) grown in this mixture.
Methods: A 2-year trial evaluated bermudagrass cultivars (“Russell” or “Tifton 85”) interseeded with alfalfa (“Bulldog 805”) under three contrasting HMS (cut only [CO], graze only [GO], or cut and graze [GC]) in Tifton, Georgia, USA. All data were analyzed for animal performance, forage, and total system performance using the PROC MIXED procedure in SAS. An economic benefit-costs analysis was performed to compare the returns to each HMS on a per-hectare and a per-head basis.
Results: Bermudagrass cultivar and HMS did not interact in any parameters evaluated (p > 0.35). Overall, HMS affected the responses more than bermudagrass cultivar. Forage and animal productivity were generally greater during the in-season grazing period compared to the deferred grazing period. Cutting management maximized total system performance (p < 0.01). Economic analysis of computer simulated feeding outcomes indicated a net return of $2831 and $1295 ha-1 yr-1 for CO and GC systems, respectively, compared to an actually achieved return of $209 ha-1 yr-1 for the GO system.
Conclusions: Based on computer-simulated feeding results, addition of cutting management to the forage system, whether CO or in addition to grazing, provided better agronomic and economic returns compared to only grazing ABG mixtures. Future research should test the feasibility of the computer-simulated results and evaluate how ecosystem services are impacted when utilizing these HMS in other ABG mixture combinations.
Background: Three water balance models were used to quantify water use efficiency on 71 golf courses in the United States. The golf courses were separated into five geographic regions.
Methods: The United States Golf Association (USGA), Tipping-Bucket (TB), and Agro-IBIS (AG) water balance models were used to estimate golf course water requirements. Actual water use was divided by the water requirement from each model to generate three water efficiency scores for each golf course (WESUSGA, WESTB, and WESAG).
Results: The mean WESUSGA was 1.16, the mean WESTB was 1.25, and the mean WESAG was 1.17. Thus, golf courses in this study used between 16% and 25% more water than predicted by the three models. The coefficients of variation of WESUSGA, WESTB, and WESAG were all 0.45 or higher, indicating that some golf courses used significantly more or less water than predicted by the models. Rooting depth, irrigated area, and soil texture were especially important modeling parameters for the golf course water requirement calculations.
Conclusions: While onsite evaluation should still be carried out to verify the assumptions made by the water balance models, the models are promising tools to quickly identify golf course superintendents who are likely to be using water efficiently and those who could use less.
Background: The symbiotic relationship between legume forages and their rhizobia is highly specific, and the effectiveness of rhizobial inoculants is often limited by local soil and climatic conditions. Therefore, identifying rhizobial strains that are well-adapted to specific environments is crucial for improving nitrogen fixation efficiency.
Methods: Four rhizobial strains were isolated from Medicago ruthenica (L.) Trautv and evaluated for their symbiotic performance with the same host plant. The most effective strain was identified based on key physiological parameters following inoculation. Response surface methodology was then applied to optimize the growth medium for the selected strain, GBXD30.
Results: Inoculation with strain GBXD30 increased plant biomass by 12%, enhanced the number of effective nodules by 3.5-fold, and boosted nitrogenase activity by 0.8-fold, compared to the reference strain USDA1844. Optimization of the fermentation medium via response surface analysis further demonstrated the potential of GBXD30 as a highly effective rhizobial inoculant suitable for alpine grassland conditions.
Conclusions: The targeted selection and application of effective rhizobial strains, such as GBXD30, are critical for maximizing nitrogen fixation in alpine legume forages. These findings offer valuable insights for developing rhizobial inoculants tailored to alpine ecosystems.
Background: Global warming impacts ecosystem carbon exchange, thus altering the carbon sink capacity of terrestrial ecosystems. However, the response of ecosystem carbon fluxes to whole-soil-profile warming remains unclear.
Methods: We first investigated the effect of whole-soil warming on ecosystem carbon fluxes in an alpine grassland ecosystem on the Qinghai-Tibet Plateau. We also compiled a database of 48 articles to examine the general patterns of experimental warming effects on these fluxes using a global meta-analysis.
Results: Our results showed that whole-soil warming elevated gross ecosystem productivity (GEP) by 14% and ecosystem respiration (ER) by 11%, but had a minor impact on net ecosystem carbon exchange (NEE) in the alpine grassland. In the meta-analysis, warming also enhanced GEP (10%-11%) and ER (13%), but did not alter NEE. Warming-induced shifts in plant community and extension of growing season may be the main reasons for the higher GEP and ER under warming, and the offset of both fluxes likely caused the minor response of NEE to warming.
Conclusions: More attention should be paid to the long-term response of ecosystem carbon fluxes to whole-soil or whole-ecosystem warming throughout the year. These novel findings may help us better predict and mitigate future climate-carbon feedback under realistic warming scenarios.
Background: Grassland researchers use many different methods to assess pasture botanical composition, but direct comparison between methods has been limited. The objective of this study was to determine an accurate and efficient method to monitor botanical composition for researchers and/or practitioners.
Methods: Six cattle farms with two pastures each were monitored across the state of Kentucky. Sampling was three times per year from fall 2020 through fall 2022. The evaluation methods included step point, visual estimation, occupancy grid, and point quadrat. The point quadrat method was designated as the reference method for accuracy comparison.
Results: The occupancy grid method had the highest statistical similarity to the reference method. The occupancy grid method was less likely to provide over- or underestimations and had the highest correlation coefficient using Pearson's method, ranging from 0.87 to 0.99 across all species. Correlations between visual estimation and the reference method ranged from 0.75 to 0.98 and the step point method had the lowest correlations, ranging from 0.40 to 0.90 due to high variability in recording certain species.
Conclusions: Analysis of variance results showed that the occupancy grid method did not differ from the point quadrat method. Overall, the occupancy grid method was the most similar to the reference method and was the most efficient method for botanical composition analysis.
Cuticular waxes, complex hydrophobic layers coating alpine grassland plants, are critical for survival in extreme environments characterized by freezing temperatures, intense UV-B radiation, and physiological drought. This review synthesizes advances in understanding the chemical diversity, biosynthesis, and ecological roles of these waxes, emphasizing their adaptive significance. This review reveals that alpine species exhibit remarkable plasticity in wax composition, with alkanes, alcohols, and specialized metabolites (β-diketones, alkylresorcinols) dynamically regulated by altitude-driven stressors. Phylogenetic analyses highlight weak taxonomic signals in wax profiles. This suggests that convergent evolution, rather than shared ancestry, is a dominant driver of chemical traits shaped by similar environmental pressures. Notably, alpine plants like Polygonum viviparum L. and Koeleria cristata Pers. employ lineage-specific strategies—such as polyketide synthase-mediated β-diketone synthesis—to balance stress resilience and ecological function. The challenges in resolving the genetic and environmental influences on wax traits are discussed, along with calls for integrated multiomics approaches to decode the molecular mechanisms underlying adaptation. Beyond ecology, we explore the ethnobotanical relevance of wax-rich species in traditional grazing systems and their potential in biotechnological applications, such as UV-protective cosmetics. By bridging fundamental research with agricultural innovation, this study positions alpine cuticular wax studies as an opportunity for addressing climate resilience and biodiversity conservation.
Background: It has been reported that bacteria and fungi play a vital role in soil biogeochemical cycles during the decomposition of animal corpses. However, it is poorly understood how the viral composition and function of grassland soil change during the decay of wild mammal corpses.
Methods: Here, we tracked soil viral succession in the 94-day decomposition of mammalian (plateau pika) wildlife corpses through metagenomic analysis, 16S rRNA gene sequencing, and soil physicochemical assessment.
Results: A total of 2413 virus species were detected, and Podoviridae, Poxviridae, Mimiviridae, and Siphoviridae were abundant in the gravesoil (soil beneath the corpse). Viral diversity first followed a trend of decline and then increased in the gravesoil with succession time. Total carbon in the gravesoil had a significant negative correlation with viral diversity and Myoviridae. Stochastic processes dominated the assembly of viral communities and decreased with succession time in both control and gravesoil groups. The network interactions between viruses and bacteria became more complex and tighter, indicating a closer and mutualistic virus-host relationship during carrion decay. Notably, the major virus-associated carbon function involved the degradation of recalcitrant carbon (e.g., lignin, chitin, pectin, and cellulose).
Conclusions: Our study broadens the understanding of the functional role of viruses that participate in the biochemical cycle of grassland soil during the decay of animal remains.
Grasslands are among the most biodiverse and ecologically important ecosystems, and yet, they are increasingly threatened by land-use intensification and biodiversity loss. Addressing these challenges requires a holistic approach that integrates knowledge across disciplines and actively engages stakeholders beyond academia. This article explores the role of collaboration, interdisciplinarity, and transdisciplinarity in grassland research, with a focus on two German key projects. The Biodiversity Exploratories are one of the largest long-term research projects investigating biodiversity and ecosystem function across land-use gradients. The BioDivKultur project examines the effects of mowing on grassland arthropods by bridging various academic and practical perspectives. Both projects highlight how integrated research approaches can generate scientifically rigorous and socially relevant solutions for biodiversity conservation while also revealing the practical and conceptual challenges of such cooperation. This article emphasizes the need for sustained cooperation, mutual learning, and effective knowledge transfer to bridge science and practice in addressing the complex, multifaceted issues of grassland ecosystems.