Adaptive Multi-paddock Grazing Research Articles

Breeding bird response to adaptive multi‐paddock and continuous grazing practices in Southeastern United States

AbstractGrassland bird populations are declining steeply, reflecting the degradation and loss of native grassland habitats. To assess how grazing management affects declining grassland bird populations, we compared breeding avifaunal communities in adaptive multi‐paddock (AMP) grazed and continuously grazed (CG) pastures in the Southeastern United States. AMP grazing involves alternating very short grazing periods at high animal densities with prolonged recovery periods across many small paddocks. Both the AMP and CG paddocks attracted obligate grassland birds during the breeding season; however, AMP‐grazed paddocks supported significantly higher detection of four obligate grassland breeding bird species. We used distance sampling techniques to account for differences in detectability for each species. The resulting densities for the grassland guild and Eastern Meadowlark as a species both revealed significantly higher densities within the AMP versus CG paddocks. Despite significantly more unadjusted detections of confirmed breeding ecotonal species, such as Blue Grosbeak, Eastern Bluebird, Brown Thrasher, Yellow‐breasted Chat, Eastern Towhee, Loggerhead Shrike, and Field Sparrow in AMP versus CG paddocks, no significant difference was found in the ecotonal guild after adjusting densities using effective detection radii. The CG paddocks supported fewer obligate grassland and ecotonal birds, with some exceptions (e.g., higher adjusted density of Eastern Bluebirds in CG) but supported comparable overall bird species richness. AMP grazing practices offer a viable strategy for increasing the diversity and abundance of obligate grassland and ecotonal breeding birds within existing cattle‐grazed landscapes in the Southeastern United States.

Adaptive multi-paddock grazing increases soil carbon stocks and decreases the carbon footprint of beef production in Ontario, Canada

Adaptive multi-paddock (AMP) grazing has been promoted to increase soil organic carbon (SOC) stocks over continuously grazed (CG) pastures; however, the evidence for this is still limited, both in terms of the number of studies conducted and the climates and biomes they cover. The objectives of this study were to determine the effect of grazing management on pasture SOC stocks and to incorporate this SOC sequestration into a life cycle assessment on the greenhouse gas (GHG) intensity (or carbon footprint) of Ontario beef production. Soil cores collected from AMP and CG pastures and annual row crop fields in southern Ontario showed that pastures managed with AMP grazing had significantly higher SOC stocks than CG pastures. Both pastures had SOC stocks higher than annual cropland, resulting in a sequestration rate of 0.957 Mg C ha−1 yr−1 for AMP and 0.507 Mg C ha−1 yr−1 for CG. Without consideration of SOC sequestration, the GHG intensity of beef production is 13.10 kg CO2eq kg LW−1, while including SOC sequestration decreased this intensity by 42% for CG pastures and by 65% for AMP. These results illustrate the importance of including pasture SOC sequestration into beef carbon footprint assessments and should encourage the adoption of AMP grazing in temperate regions to achieve environmental goals.

The LTAR Grazing Land Common Experiment at the Central Plains Experimental Range: Collaborative adaptive rangeland management.

Semiarid rangelands throughout the western Great Plains support livestock production and many other ecosystem services. The degree to which adaptive multi-paddock (AMP) grazing management approaches can help achieve desired ecosystem services remains unclear. At the Central Plains Experimental Range in northeastern Colorado, a management-science partnership with a diverse stakeholder group is comparing collaborative adaptive rangeland management (CARM), designed to incorporate AMP principles, to traditional rangeland management (TRM), consisting of season-long grazing during the growing season. Each treatment was implemented on a set of 10, 130-ha pastures paired by soils, topography, and plant communities to evaluate how CARM affects vegetation (composition and production), livestock production (steer weight gain), and wildlife habitat (vegetation structure for grassland birds). For the first 5 years of the experiment, CARM cattle were managed as a single herd using AMP grazing with planned year-long rest in 20% of the pastures. Relative to TRM, CARM enhanced heterogeneity in vegetation structure across the landscape, benefiting two grassland bird species. However, this came at the cost of 12%-16% lower steer weight gains in CARM versus TRM and declining populations of a third bird species of conservation concern in both treatments. Here we discuss how increased understanding of ecological and social processes during the experiment's first 5 years led to changes in the CARM treatment and management objectives during the next 5 years. We also discuss how innovations in remote sensing, environmental sensors, ecosystem modeling, social learning, and economic analyses are being integrated into and supported by the CARM experiment.

Adaptive Grazing of Native Grasslands Provides Ecosystem Services and Reduces Economic Instability for Livestock Systems in the Flooding Pampa, Argentina

There is a widespread concern about the negative impact of intensive livestock farming on climate change and biodiversity loss. We analyzed the trade-off between meat production and environmental variables related to global warming—energy consumption, use efficiency of energy, greenhouse gas (GHG) emissions, carbon footprint, and GHG balance—of two alternative intensification strategies of livestock farming in the Flooding Pampa: conventional intensification (CI) based on external inputs, and ecological intensification (EI) based on maintaining native grassland in good condition through adaptive multi-paddock grazing (AMPG). We also explored the relationship between meat production and the economic variables gross margin and its year-to-year variation. Energy consumption was positively correlated with meat production (ρ = 0.95, p= 0.0117), and EI farms consumed less fuel energy and showed higher energy use efficiency than CI farms (294 ± 152 vs. 2740 ± 442 MJ ha−1 y−1, 38.4 ± 28.8 vs. 1.23 ± 0.13 MJ kg LW−1 y−1, p < 0.05, respectively). GHG emissions and carbon footprint did not show significant differences between EI and CI strategies. As soil carbon sequestration was significantly higher in EI farms than in CI farms (1676 ± 304 vs. −433 ± 343 kg CO2eq ha−1 y−1, p <0.05), GHG balance resulted almost neutral and higher under the EI strategy (−693 ± 732 vs. −3520 ± 774 kg CO2eq ha−1 y−1, p < 0.05). CI strategy obtained higher meat production but a similar gross margin to the EI strategy and a more unstable economic return, as the coefficient of variation in the gross margin doubled that of the EI strategy (84 + 13.3 vs. 43 + 2.6, respectively, p < 0.05). Ecological intensification of cattle production in the Flooding Pampa demonstrates the potential for a positive relationship between individual cattle farmers’ profits and overall societal benefits, as reflected in improved environmental performance.

Adaptive multi-paddock grazing increases mineral associated soil carbon in Northern grasslands

Grassland soils play an important role in sequestering carbon (C) and are primarily used for livestock grazing. Grazing management can increase the amount of C stored in soils and the distribution of C in different soil fractions by altering soil microbial community structure, thereby influencing the persistence of soil C over time. Adaptive multi-paddock grazing (AMP), grazing cattle at high stock densities with long periods between grazing events, is considered to enhance grassland sustainability, productivity, and soil C compared to more conventional grazing practices (continuous to slow rotational). However, whether and how AMP grazing might affect the amount of C stored in different soil fractions has received little attention. Soil samples (0–15 cm depth) were collected from 24 ranches in a paired design, where 12 ranches practiced AMP grazing and 12 neighboring ranches practiced conventional grazing. Soil organic C (SOC) and total nitrogen were measured in different soil particle size [fine (<53 µm), medium (53–250 µm) and coarse (>250 µm)], and density [light (>1.6 g cm−3), and heavy (<1.6 g cm−3)] fractions. Soil bacterial and fungal biomass and abundances were obtained from phospholipid fatty acid analysis. Mean weights of soil microaggregates and heavy fractions were higher in soil exposed to AMP grazing, whereas mean weights of macroaggregates and light fractions were higher in conventionally grazed soils. In warmer and drier climatic conditions, SOC in both bulk soils and within various size and density fractions tended to decrease. Soil organic C (both concentration and stock) were significantly higher in the fine soil fractions under AMP management than conventionally grazed grasslands. Given that SOC in fine fractions, is more mineral associated and recalcitrant, our results indicate that AMP grazing increased the size of the stable SOC pool. The increased carbon pool in the fine fraction was associated with greater fungal to bacterial ratios, suggesting a possible biological mechanism for the increase. Overall, the results indicate that AMP grazing may be beneficial for sequestering more stable carbon that helps mitigate the effects of climate change.

Adaptive multi-paddock grazing management reduces diet quality of yearling cattle in shortgrass steppe

Adaptive multi-paddock (AMP) grazing is hypothesised to improve livestock diet quality by allowing managers to move livestock among paddocks in a manner that tracks phenological variation in forage growth related to variation in plant community composition. We compared yearling steer (Bos taurus) dietary crude protein (CP), digestible organic matter (DOM), and diet composition on a ranch-scale (2600 ha, 10 pairs of 130 ha paddocks) experiment in shortgrass steppe for 6 years (2014–2019) in contrasting grazing treatments: Collaborative Adaptive Rangeland Management (CARM, a type of AMP with a stakeholder group making science-informed management decisions within the grazing season) and season-long, continuous grazing (TRM, traditional rangeland management). These grazing treatments had the same system-level stocking rate annually but differed in stocking density, with CARM being 10-fold higher than TRM because of all steers in the CARM treatment being in a single herd. Mean grazing-season dietary CP was consistently 13–28% higher in TRM than CARM; in contrast, DOM in TRM was similar to CARM or only slightly higher (2.5%). Differences in diet quality between CARM and TRM grazing strategies were largest early in the grazing season, with CP being 14–36% higher for TRM compared to CARM steers during the first 4 weeks; these diet-quality differences between treatments disappeared towards the end of the grazing season. Implementing AMP on the basis of a diverse stakeholder group’s experiential knowledge about plant communities, soils, and ecological sites did alter within-grazing season plant functional group contributions to steer diets. Although we implemented adaptive decision-making within the grazing season, which allowed CARM steers to track the seasonal phenology of C3 versus C4 grasses as steers rotated among paddocks varying in plant community composition, these adaptive movements did not offset the detrimental effects on diet quality associated with grazing in a herd with 10-fold higher stocking density. Managers applying AMP in semiarid rangelands should be cognisant that high stocking density can be associated with lower diet quality early in the growing season, which can compromise livestock gain responses.

Cattle grazing management affects soil microbial diversity and community network complexity in the Northern Great Plains

Soil microbial communities play a vital role in the biogeochemical cycling and ecological functioning of grassland, but may be affected by common land uses such as cattle grazing. Changes in microbial diversity and network complexity can affect key ecosystem functions such as nutrient cycling. However, it is not well known how microbial diversity and network complexity respond to grazing in the Northern Great Plains. Consequently, it is important to understand whether variation in grazing management alters the diversity and complexity of grassland microbial communities. We compared the effect of intensive adaptive multi-paddock (AMP) grazing and conventional grazing practices on soil microbial communities using 16S/ITS amplicon sequencing. Samples were collected from grasslands in 13 AMP ranches and 13 neighboring, conventional ranches located across the Canadian prairies. We found that AMP grazing increased fungal diversity and evenness, and led to more complex microbial associations. Acidobacteria, Actinobacteria, Gemmatimonadetes, and Bacteroidetes were keystone taxa associated with AMP grazing, while Actinobacteria, Acidobacteria, Proteobacteria, and Armatimonadetes were keystone taxa under conventional grazing. Besides overall grazing treatment effects, specific grazing metrics like cattle stocking rate and rest-to-grazing ratio affected microbial richness and diversity. Bacterial and fungal richness increased with elevated stocking rate, and fungal richness and diversity increased directly with the rest-to-grazing ratio. These results suggest that AMP grazing may improve ecosystem by enhancing fungal diversity and increasing microbial network complexity and connectivity.

Grazing management impacts on ecosystem services under contrasting climatic conditions in Texas and North Dakota

Grazing management is an important factor affecting the delivery of ecosystem services at the watershed scale. Moreover, characterizing the impacts of climate variation on water resources is essential in managing rangelands. In this study, the effects of alternative grazing management scenarios on provisioning, regulating, and supporting services were assessed in two watersheds with contrasting climates; the Lower Prairie Dog Town Fork Red River (LPDTFR) Watershed in North Texas and the Apple Watershed in South Dakota. The impacts of heavy stocking continuous grazing, light stocking continuous grazing, Adaptive Multi-Paddock (AMP) grazing, and an ungrazed exclosure were compared using the Soil and Water Assessment Tool (SWAT) model. Our results indicate that the quantity of snow and timing of snow melt substantially influenced grazing management effects on ecosystem services in the Apple Watershed. In contrast, precipitation was the main factor influencing these effects in the LPDTFR Watershed because it highly affected the variation in water cycling, streamflow, sediment, and nutrient controls. Simulated results indicated that AMP grazing was the optimal grazing management approach for enhancing water conservation and ecosystem services in both watersheds regardless of climatic conditions. The Apple Watershed, which is a snow-dominated watershed, exhibited greater ecosystem service improvements under AMP grazing (50.6%, 58.7%, 74.4%, 61.5% and 72.6% reduction in surface runoff, streamflow, and sediment, total nitrogen (TN) and total phosphorus (TP) losses, respectively as compared to HC grazing) than the LPDTFR Watershed (46.0%, 22.8%, 34.1%, 18.9% and 38.4% reduction in surface runoff, streamflow, and sediment, TN and TP losses, respectively). Our results suggest that improved grazing management practices enhance ecosystem services and water catchment functions in rangeland-dominated areas, especially in colder climates.

Assessing the effect of rotational grazing adoption in Iberian silvopastoral systems with Normalized Difference Vegetation Index time series

Adaptive Multi-Paddock (AMP) is a grazing system which combines intensive, rapid grazing livestock rotation with relatively short grazing periods and long recovery time after grazing. The study assesses, under Mediterranean silvopastoral systems, changes in pasture phenology and spatial variability after adopting the AMP under contrasting land cover (Wooded Grassland vs Grassland ) with a remote sensing approach based on the time-series analysis of Normalized Difference Vegetation Index (NDVI) from remote sensing through Landsat satellite. The study revealed an overall positive effect of rotational grazing on pasture phenology and NDVI spatial variability. The AMP adoption resulted in higher estimated values of NDVI at the beginning (under grassland land cover), the end, and the peak of the growing season, while no differences were observed in parameters estimating the length of the growing season. The spatial variability of NDVI was always lower under AMP than in continuously grazed areas, except in the early stages of the growing season under grassland land cover. The results suggested that in a relatively short period (4-5 years), the AMP grazing system can represent a strategy to improve forage availability and exploitation by grazing animals under low stocking rates in extensively managed Mediterranean silvopastoral systems.

Using Mid-Infrared Spectroscopy to Optimize Throughput and Costs of Soil Organic Carbon and Nitrogen Estimates: An Assessment in Grassland Soils

Low-cost techniques, such as mid-infrared (MIR) spectroscopy, are increasingly necessary to detect soil organic carbon (SOC) and nitrogen (N) changes in rangelands following improved grazing management. Specifically, Adaptive Multi-Paddock (AMP) grazing is being implemented to restore grassland ecosystems and sequester SOC often for commercialization in C markets. To determine how the accuracy of SOC and N predictions using MIR spectroscopy is affected by the number of calibration samples and by different predictive models, we analyzed 1000 samples from grassland soils. We tested the effect of calibration sample size from 100 to 1000 samples, as well as the predictive ability of the partial least squares (PLS), random forest (RF) and support vector machine (SVM) algorithms on SOC and N predictions. The samples were obtained from five different farm pairs corresponding to AMP and Conventional Grazing (CG), covering a 0–50 cm soil depth profile along a latitudinal gradient in the Southeast USA. Overall, the sample size had only a moderate influence on these predictions. The predictive accuracy of all three models was less affected by variation in sample size when &gt;400 samples were used. The predictive ability of non-linear models SVM and RF was similar to classical PLS. Additionally, all three models performed better for the deeper soil samples, i.e., from below the A horizon to the –50 cm depth. For topsoil samples, the particulate organic matter (POM) content also influenced the model accuracy. The selection of representative calibration samples efficiently reduces analysis costs without affecting the quality of results. Our study is an effort to improve the efficiency of SOC and N monitoring techniques.

Evaluating the impacts of alternative grazing management practices on soil carbon sequestration and soil health indicators

Globally, grazing lands represent a major carbon (C) sink. However, improper use of these ecosystems can degrade their soils and their C storage capacity. Specifically, prolonged high stocking rates in livestock production can result in significantly less soil organic carbon (SOC) and soil fertility in grazing lands. This underlines the need to assess key soil health indicators to determine the ecological efficacy of grazing management. The objective of this study was to identify the impacts of alternative grazing management practices, including heavy continuous (HC), light continuous (LC), and adaptive multi-paddock (AMP) grazing, on SOC and soil health indicators at the ranch and watershed scales in the Lower Prairie Dog Town Fork Red River Watershed in Northwest Texas. The stocking rate was the same under AMP and HC grazing, and it was reduced by half under LC grazing. The Soil and Water Assessment Tool-Carbon (SWAT-C) model was modified and used to conduct this assessment over a 40 year period (1979–2018), after a 900-year spin-up simulation (800 years under natural condition and 100 years under the HC grazing) to initiate the SOC pool. The simulated SOC was validated using observed data from several sampling locations. The study results indicated that when grazing management at the study ranch was changed from the current AMP grazing to hypothetical HC grazing, simulated average annual SOC decreased from 84 to 81.8 Mg/ha (a 2.6% decline). At the watershed-scale, when the grazing management was changed from the baseline HC grazing to AMP grazing, the simulated average annual SOC increased from 35.6 to 38.3 Mg/ha (a 7.5% increase). The net primary productivity (NPP), evapotranspiration (ET), biomass C, and soil nitrogen (N) increased, while C losses from runoff, and sediment loads decreased under AMP grazing. These results indicate that compared to HC, AMP grazing performed better with respect to SOC increase, and improvement of soil ecosystem and hydrological functions at both the ranch and watershed scales in the study watershed. Our findings suggest the need to shift from continuous to AMP grazing in order to improve soil health at multiple spatial scales. Data availability statementThe data that support the findings of this study are available from the corresponding author upon reasonable request.

Links of microbial and vegetation communities with soil physical and chemical factors for a broad range of management of tallgrass prairie

Identifying ecological indicators and management factors that influence sustainability and resilience, both ecologically and economically, is key to restoring grassland landscapes' ecological function. We examine soil and vegetation responses to different combinations of adaptive multi-paddock grazing (AMP) managed to improve soil and ecological function as the foundation to improve the provision of ecosystem services and economic benefits, relative to heavy continuous grazing (HCG) and moderate continuous grazing (MCG).We used multidimensional scaling (MDS) and analysis of similarities (ANOSIM) to indicate associations among soil, soil biota and vegetation parameters to indicate associations in response to the different grazing management strategies. AMP grazing improved total herbaceous biomass, C4 tallgrasses, native perennial summer growing forbs, and vegetation cover while decreasing bare ground cover and less productive or invasive herbaceous species. AMP also had higher biomass of total soil microbes, actinomycetes, and gram-positive and gram-negative bacteria associated with improved soil aggregation and nutrient cycling than HCG, with MCG having intermediate responses. Arbuscular mycorrhizal fungi crucial for enhanced water and nutrient acquisition by plants were higher with AMP and were lower with HCG, with MCG intermediate between the two. AMP also outperformed HCG and usually MCG in the critical soil physical elements such as soil aggregation fostering improved ecological function. These are substantive improvements, achieved despite AMP having double the stocking rate of MCG. These positive outcomes were generally not compromised with the BURN and HAY treatments as both were managed with AMP grazing. The exception was HAY, which showed increased soil penetration resistance compared to AMP but less than with HCG or MCG. AMP grazing also compared favorably with the grazing Exclosures for most parameters measured. The presence of low densities of trees had predominantly positive results relative to treeless AMP and MCG, particular for soil temperature, soil organic matter and cation exchange capacity. These findings provide evidence that AMP grazing is a powerful management strategy to positively alter plant composition and soil physical, chemical, and microbial properties relative to season-long continuous grazing to enhance the provision of ecosystem services and economic benefits in Southern Tallgrass prairie.

Adaptive multi-paddock grazing and wellbeing: uptake, management practices and mindset among Canadian beef producers

ABSTRACT Adaptive multi-paddock (AMP) grazing practices have been debated based on production, environmental and workload impacts, but farmer wellbeing is only beginning to be explored. A panel-based online survey of 200 Canadian beef producers was undertaken in early 2020 with a descriptive aim to explore the uptake, management, mindsets, and wellbeing implications associated with AMP grazing. AMP practices were more common than expected (29%) as well as distinct in grazing regime, featuring fast rotation, and long rests. AMP ranchers reported high physical wellbeing, as well as systems thinking, nontraditional values, a priority for enjoying life and tendency to use a wide range of modes to learn about grazing. Other dimensions of wellbeing, environmental motivations, and gender dimensions suggested by smaller-n studies were not associated with AMP grazing in this work. These insights are important as the federal government begins to promote AMP grazing and its variants as strategies to combat climate change. More nuanced understanding of adaptive grazing and its trajectory would be possible via consistent, longitudinal surveys with improved operationalization of wellbeing concepts, more detailed exploration of educational background, inclusion of religious beliefs, and elucidation of management characteristics beyond grazing regime variables.

Adaptive multi-paddock grazing management's influence on soil food web community structure for: increasing pasture forage production, soil organic carbon, and reducing soil respiration rates in southeastern USA ranches.

BackgroundMeasurement of two grazing management’s influence on pasture productivity, soil food web structure, soil organic carbon and soil microbial respiration efficiency was conducted on five southeastern US, across-the-fence ranch pairs to compare adaptive multi-paddock grazing (AMP) management, using short grazing events with planned, adaptive recovery periods, to conventional grazing (CG) management, with continuous grazing at low stock density.MethodologyA point-in-time experimental field analysis was conducted to compare five AMP or CG ranch pairs to better understand the influence of grazing management on (a) standing crop biomass productivity; (b) soil food web community population, structure and functionality; (c) soil organic carbon accrual; and d) soil-C (CO2) respiration kinetics.ResultsAMP grazing systems outperformed CG systems by generating: (a) 92.68 g m−2 more standing crop biomass (SCB), promoting 46% higher pasture photosynthetic capacity (Two sample Mann-Whitney; Z = 6.1836; no DF in MW; p = 6.26 × 10−10; Effect size = 0.35) (b) a strong positive linear relationship of SCB with fungal biomass (R = 0.9915; F(1,3) = 175.35; p = 0.015); fungal to bacterial (F:B) biomass ratio (R = 0.9616; F(1,3) = 36.75; p = 0.009) and a soil food web proxy (R = 0.9616; F(1,3) = 36.75; p = 0.009) and a concurrent very strong inverse relationship with bacteria biomass (R = −0.946; F(1,3) = 25.56; p = 0.015); (c) significant predator/prey interactions with an inverse relationship with bacterial population biomass (R = − 0.946; F(1,3) = 25.56; p = 0.015) and a positive relationship with total protozoa enumeration (R = 0.9826; F(1,3) = 83.68; p = 0.003) when compared to SCB; (d) a 19.52% reduction in soil C (CO2) respiration rates (Two sample t-test; T = −2.3581; DF = 52.3541; p = 0.0221; Effect size = 0.59); and (e) a 20.6% increase in soil organic carbon (SOC) in the top 10 cm of soil profile (Two sample Mann–Whitney; Z = 2.6507; no DF in MW; p = 0.008; Effect size = 0.24). Rancher conversion to AMP grazing strategies would appear to regenerate soil food web population, structure, diversity and biological functionality helping to improve: carbon flow into plant biomass, buildup of soil carbon, predator/prey nutrient cycling and soil microbial respiration efficiency while offering improved climate resilience and a strategy to increase the capture and storage of atmospheric CO2 in soils of the world’s rangeland.

Adaptive multi-paddock grazing increases soil nutrient availability and bacteria to fungi ratio in grassland soils

Grasslands are used extensively for grazing livestock, and variation in grazing management may affect the soil microbial community and ecosystem functions, such as nutrient cycling, in grasslands. In particular, adaptive multi-paddock (hereafter ‘multi-paddock’) grazing is considered a regenerative grazing management practice that can improve the sustainability of grasslands. However, little is known about how multi-paddock grazing affects the soil microbial community, which plays an importance role in global biogeochemical cycling. In this study, grassland soils were collected from 15 ranch pairs located across the Canadian prairie, where, in each pair, one ranch practiced multi-paddock grazing while the other practiced conventional grazing (varying from continuous to slow to fast rotational grazing). We used soil phospholipid fatty acid (PLFA) profiles to quantify microbial functional groups, and measured microbial biomass C and soil properties. Our data show that microbial PLFA abundances and microbial biomass C was not different between the two grazing systems. However, multi-paddock grazing resulted in lower ratios of microbial biomass C: N (MBC:MBN), fungi: bacteria (F:B) and Gram-positive: Gram-negative bacteria in grassland soils compared to conventional grazing. Further investigation of specific management metrics revealed that MBC:MBN and F:B ratios were most affected by cattle stocking rate and stocking density, respectively. Thus, there is potential to affect soil function by altering the composition of soil microbial communities through multi-paddock grazing.

Improvements in soil properties under adaptive multipaddock grazing relative to conventional grazing

AbstractWithin managed ecosystems, such as some livestock grazed grasslands, soil physical, chemical, and biological properties may be severely compromised relative to native grasslands. Conventional grazing (CG) management, commonly referred to as continuous grazing, can affect soil properties and health by reducing soil C stocks and other available nutrients, while creating bare patches in vegetation that may enhance erosion and runoff. In contrast, adaptive multipaddock (AMP) grazing, an intensive form of rotational grazing that moves dense cattle herds quickly over the land followed by rest periods for the regrowth of plants, has been proposed as a regenerative grassland management tool that can improve soil properties such as soil C stocks, soil structure, as well as nutrient and water retention. Our research analyzed soils from 10 grasslands in the southeast United States representing either CG or AMP grazing management. We analyzed the A‐horizons of these soils for physical, chemical, and biological properties considered indicators of soil health across each management type. Chemical soil properties (e.g., cation exchange capacity [CEC], base saturation [BS], electrical conductivity [EC]) were improved where AMP grazing management was implemented. Additionally, farms using AMP grazing management had greater A‐horizon C and N stocks in bulk soils and across multiple soil organic matter (SOM) fractions. No biological indicators measured were affected by the grassland management except potential N mineralization rate, which was lower under AMP. Taken together, these results provide evidence that AMP grazing management could be implemented to regenerate several grassland soil properties across land currently under conventional grazing management.

Vegetation, water infiltration, and soil carbon response to Adaptive Multi-Paddock and Conventional grazing in Southeastern USA ranches

We examine Adaptive Multi-Paddock (AMP) grazed with short grazing events and planned recovery periods and paired ranches using Conventional Continuous Grazing (CG) at low stock density on vegetation, water infiltration, and soil carbon across SE USA. Increased vegetation standing biomass and plant species dominance-diversity were measured in AMP grazed ranches. Invasive perennial plant species richness and abundance increased with AMP grazing in the south, while in the north they increased on CG grazed ranches. Percent bare ground was significantly greater in CG at the Alabama and Mississippi sites, no different at the Kentucky and mid-Alabama sites, and greater on AMP at the Tennessee pair. On average, surface water infiltration was higher on AMP than paired CG ranches. Averaged over all locations, soil organic carbon stocks to a depth of 1 m were over 13% greater on AMP than CG ranches, and standing crop biomass was >300% higher on AMP ranches. AMP grazing supported substantially higher livestock stocking levels while providing significant improvements in vegetation, soil carbon, and water infiltration functions. AMP grazing also significantly increased available forage nutrition for key constituents, and increased soil carbon to provide significant resource and economic benefits for improving ecological health, resilience, and durability of the family ranch.

A review of transformative strategies for climate mitigation by grasslands

Grasslands can significantly contribute to climate mitigation. However, recent trends indicate that human activities have switched their net cooling effect to a warming effect due to management intensification and land conversion. This indicates an urgent need for strategies directed to mitigate climate warming while enhancing productivity and efficiency in the use of land and natural (nutrients, water) resources. Here, we examine the potential of four innovative strategies to slow climate change including: 1) Adaptive multi-paddock grazing that consists of mimicking how ancestral herds roamed the Earth; 2) Agrivoltaics that consists of simultaneously producing food and energy from solar panels on the same land area; 3) Agroforestry with a reverse phenology tree species, Faidherbia (Acacia) albida, that has the unique trait of being photosynthetically active when intercropped herbaceous plants are dormant; and, 4) Enhanced Weathering, a negative emission technology that removes atmospheric CO2 from the atmosphere. Further, we speculate about potential unknown consequences of these different management strategies and identify gaps in knowledge. We find that all these strategies could promote at least some of the following benefits of grasslands: CO2 sequestration, non-CO2 GHG mitigation, productivity, resilience to climate change, and an efficient use of natural resources. However, there are obstacles to be overcome. Mechanistic assessment of the ecological, environmental, and socio-economic consequences of adopting these strategies at large scale are urgently needed to fully assess the potential of grasslands to provide food, energy and environmental security.

Soil greenhouse gas emissions and grazing management in northern temperate grasslands

Adaptive multi-paddock (AMP) grazing, a grazing system in which individual paddocks are grazed for a short duration at a high stock density and followed by a long rest period, is claimed to be an effective tool to sustainably manage and improve grasslands and enhance their ecosystem services. However, whether AMP grazing is superior to conventional grazing (n-AMP) in reducing soil greenhouse gas (GHG) emissions is unclear. Here, we measured CO2, CH4, and N2O fluxes between August 2017 and August 2019 in 12 pairs of AMP vs. n-AMP ranches distributed across an agro-climatic gradient in Alberta, Canada. We found that field GHG fluxes did not differ between AMP and n-AMP grazing systems, but instead were regulated by specific management attributes, environmental conditions, and soil properties, including cattle stocking rate, cultivation history, soil moisture content, and soil bulk density. Specifically, we found that seasonal mean CO2 emissions increased with increasing cattle stocking rates, while CH4 uptake was lower in grasslands with a history of cultivation. Seasonal mean CO2 emissions increased while CH4 uptake decreased with increasing soil moisture content. In addition, CH4 uptake decreased with increasing soil bulk density. Observed N2O emissions were poorly predicted by the management, environmental conditions, and soil properties investigated in our study. We conclude that AMP grazing does not have an advantage over n-AMP grazing in reducing GHG fluxes from grasslands. Future efforts to develop optimal management strategies (e.g., the use of sustainable stocking rates and avoided cultivation) that reduce GHG emissions should also consider the environmental conditions and soil properties unique to every grassland ecosystem.

Adaptive multi-paddock grazing improves water infiltration in Canadian grassland soils

The maintenance of hydrologic function on grazing lands is an important management objective to sustain forage production during low moisture supply, safeguard other ecosystem goods and services and build resilience to a warming climate. Hydrologic function can be influenced by grazing patterns, as represented by variation in the timing, intensity and frequency of livestock use. While rotational, adaptive grazing (a short-duration, multi-paddock grazing system that emphasises plant recovery between grazing events) is growing in popularity and has the potential to influence grassland hydrological processes such as water infiltration, few studies have comprehensively examined infiltration in relation to on-ranch grazing practices. We examined water infiltration in grasslands on 52 ranches (set up as matched pairs) to examine whether adaptive grazing alters water infiltration in the Great Plains of western Canada, as compared to conventional grazing management employed on neighbouring ranches. We also used producer survey information to test for the influence of ongoing nuanced grazing practices on water infiltration rates, over and above the biophysical effects of soil texture, soil bulk density and plant litter, as well as cultivation history and climate. Overall, adaptive grazing, and specifically the use of higher rest-to-grazing ratios early in the growing season (prior to August 1), led to increased water infiltration in grassland soils. Water infiltration was positively associated with increased litter mass under adaptive grazing, whereas higher bulk density (and sandier) soils were associated with decreased infiltration rates. This study highlights the potential of specialised rotational grazing systems using cattle to improve soil hydrologic function in grazed grasslands.