Background: As grasslands decline, grassland-dependent species such as grassland butterflies have experienced widespread population losses. To manage remaining grasslands, prescribed fire, grazing, and haying are common management practices across the Southern Great Plains of the United States. However, the impacts of management and land use intensity (LUI) on butterfly community composition and butterfly community traits are not well understood. Additionally, local habitat characteristics such as vegetation height and cover, as well as broader landscape categorization, including how much agriculture or urbanization is occurring around the habitat, can alter butterfly communities.

Methods: We conducted standardized butterfly and flowering forb surveys at grassland sites across north-central Oklahoma.

Results: LUI influenced overall butterfly community composition with sites managed only with fire having the most dissimilar butterfly community compared to three other management regimens. The amount of agriculture, urbanization, and wetlands surrounding study sites also influenced butterfly community composition. Flowering forb community measures differed by site with sites managed by fire alone having lower blooming forbs species richness, diversity, and abundance than sites with other management regimens.

Conclusions: Sites managed with only prescribed fire had the most disparate butterfly community in comparison to other management methods, suggesting that specialist butterfly species may be sensitive to increasing disturbance.

Background: There is limited knowledge on how to increase soil organic carbon (SOC) stocks under tropical conditions. This study investigates SOC changes after converting land from native savanna (NS) to improved pasture (IP) land use.

Methods: Two acidic soil conversion sites were examined: (i) a poorly drained slope with medium-texture soil (Casanare [CAS]₁) and (ii) flat terrain with fine-texture soil (CAS₂). Another flat site was evaluated (Atlántico [ATL]), with fine-textured to moderately textured neutral soil. Soil samples were collected and analyzed. SOC stocks (0–60 cm soil depth) were estimated, with a complex analysis of variance analyzing pasture type and soil depth.

Results: NS to IP conversion resulted in significant SOC accumulation in two regions, with losses in one (CAS₂). ATL showed higher SOC accumulation than CAS. IP adoption led to SOC accumulation at depth (0–60 cm) after 10 years in CAS₁. Elevated clay content in CAS₂ favored SOC storage, while poorly drained areas hindered accumulation in CAS₁. Cultivating rice before IP at CAS₂ likely depleted SOC (0–20 cm), with 4 years of IP not restoring initial levels.

Conclusions: Adopting IP over NS can increase SOC. Grassland type, soil properties, and land-use change all influence SOC accumulation. These data inform sustainable land management for low-emission livestock production.

Background: Despite its importance to animal production potential, genetic gain for forage nutritive value has been limited in perennial ryegrass (Lolium perenne L.) breeding. The objective of this study was to phenotype a training population and develop prediction models to assess the potential of predicting organic matter digestibility (OMD) and neutral detergent fiber (NDF) with genotyping-by-sequencing data.

Methods: Near infra-red reflectance spectroscopy calibrations for OMD and NDF were developed and used to phenotype a spaced plant training population of n = 1606, with matching genotype-by-sequencing data, for developing genomic selection models. F₂ families derived from the training population were also evaluated for OMD and NDF in sward plots and used to empirically validate prediction models.

Results: Sufficient genotypic variation exists in breeding populations to improve forage nutritive value, and spectral bands contributing to calibrations were identified. OMD and NDF can be predicted from genomic data with moderate accuracy (predictive ability in the range of 0.51–0.59 and 0.33–0.57, respectively) and models developed on individual plants outperform those developed from family means. Encouragingly, genomic prediction models developed on parental plants can predict OMD in subsequent generations grown as competitive swards.

Conclusions: These findings suggest that genetic improvement in forage nutritive value can be accelerated through the application of genomic prediction models.

Background: Grazing approaches are needed to increase the resilience of perennial ryegrass (Lolium perenne L.)-based pastures subject to increasing drought stress. One opportunity has focused on seedhead management in late spring. Paddock-level studies demonstrated increased pasture resilience when ryegrass seedheads are allowed to mature, but knowledge is lacking on how defoliation management affects plant carbohydrate status and hence resilience in the sward.

Methods: A glasshouse study was conducted from spring to autumn using 1m deep root tubes. Plant growth and water-soluble carbohydrate (WSC) reserves were measured every 4–6 weeks. Defoliation treatments comprised “VEGETATIVE”—regular defoliation based on leaf stage and trimmed to 4 cm; “FLOWERING”—no defoliation spring to anthesis; and “SENESCENT”—no defoliation spring to reproductive tiller senescence. Thereafter, regular defoliation was carried out for all treatments until the end of the study. From spring to the end of summer, plants were watered daily in WET (no drought, well watered) and on four occasions in DRY (drought) treatments, with daily watering thereafter.

Results: Herbage mass, tillering, root depth, root mass, andWSC were generally higher in SENESCENT than VEGETATIVE with FLOWERING intermediate (p < 0.05). Nutritive values were similar in VEGETATIVE and FLOWERING, but in SENESCENT, metabolizable energy and crude protein declined and neutral detergent fiber increased (p < 0.05). Soil moisture effects were small, with the DRY treatment resulting in moderate suppression of herbage growth and a minor reduction in WSC reserves (p < 0.05).

Conclusions: Results were consistent with field studies and recommendations to allow perennial ryegrass tillers to set seed to improve pasture resilience.

Background: Pearl millet is characterized by its high dry matter (DM) yields with a high moisture content, which makes it difficult to process as silage.

Methods: Pearl millet was sown in mid-September for 3 years to examine its growth, DM yields in early December, and decrease in DM percentage after frost exposure. The crop was processed as round-bale silage to assess silage quality and preference by breeding beef cattle.

Results: Plants reached a height of 160–200 cm, with heading tiller percentages of 50%–70% in early December. With frost exposure, DM percentage increased in leaves and panicles, followed by stems, reaching over 40%, 1 month after exposure. These increases were positively correlated with cumulative frost exposure. After frost exposure, in vitro DM digestibility and crude protein content declined while acid detergent fiber content increased. Repeated cafeteria feeding experiments showed a reduced preference for either pearl millet silage or Italian ryegrass hay. The silage showed moderate acidity at pH 4.73–5.40, with lactic acid at 0.58%–1.62% DM, acetic acid at 0.03%–0.10% DM, and negligible butyric acid, indicating a satisfactory quality.

Conclusions: In Southern Kyushu, pearl millet sown in late summer can be processed into low-moisture round-bale silage in January, the year following sowing.

Background: The regional species pool and local community assembly processes shape the biogeographic patterns of soil bacterial community diversity. However, how community assembly mechanisms regulate biogeographic patterns in rare and abundant bacterial communities remains unclear.

Methods: Soil samples of 16 grassland habitats across the Inner Mongolian Plateau and Qinghai-Tibet Plateau (QTP) transects were collected to investigate the variation of β-diversity in rare taxa (RT) and abundant taxa (AT). Highthroughput sequencing analysis of 16S rRNA gene amplicons was implemented on an Illumina MiSeq platform.

Results: Significant distance-decay relationships of β-diversity in RT and AT were observed at transect and habitat scales, and the turnover rate increased from desert to meadow steppe in both taxa. For variations of β-diversity along environmental gradient, the regional species pool had a limited effect on both taxa except RT in QTP. Deterministic processes, including homogeneous selection (85.1%–97.3%) and heterogenous selection (48.1%–64.2%), dominated the assembly of RT at both the transect and habitat scales. In contrast, the assembly of AT exhibited habitat specificity and was dominated by homogeneous selection (47.2%–80.6%), heterogenous selection (42.1%–54.2%), and dispersal limitation (41.8%) in different transects and habitats. Moreover, the local assembly processes of the AT community were more stochastic than those of the RT community. Mean annual precipitation (MAP) was the dominant driver of community assembly at the transect scale, with extreme MAP (<200 or >400mm) resulting in more deterministic processes and a moderate level of MAP (200–400mm) leading to more stochastic processes. However, the effects of geographical distance and soil properties on different grassland habitats cannot be ignored.

Conclusions: Although both bacterial taxa exhibited significant distance-decay patterns, different assembly mechanisms shaped the β-diversity of AT and RT communities in grassland soils. Our results suggested that MAP can mediate community assembly of soil bacteria on a large scale.