Grazing Treatments Research Articles

Effects of grazing corn plant residue on beef cattle performance, residue characteristics, and subsequent crop yield

Our objective was to evaluate the effects of grazing method on beef cattle performance, residue characteristics, and subsequent corn grain yields. This was a 3-yr study in which strip-grazing (SG), continuous grazing (CG), and ungrazed control (CT) treatments were arranged in a randomized complete block design with 3 replications per year on a continuous corn production system in central Illinois. Strip-grazed plots were divided into subplots (1, 2, 3) in which cattle back-grazed. Thirty-six spring-calving, multiparous, Angus cows were used in the first and second year of the study and 42 winter-calving Angus heifers were used in the third year. Cattle grazed for 42 d each year following corn harvest. Cattle in SG plots were 9.8 kg heavier ( P = 0.05) postgrazing compared with those on CG plots but did not differ ( P = 0.77) in final BCS, indicating adequate performance was maintained regardless of treatment. The SG and CG plots had increased ADF ( P = 0.03) and decreased CP ( P < 0.01) after grazing compared with CT. In year 2 postgrazing, SG and CG had decreased ( P < 0.01) total residue availability, leaves and husks, and cobs compared with CT, suggesting more digestible, nutrient-dense components were selected during grazing. No differences ( P = 0.16) were detected for corn yield among grazing treatments. However, yield was different ( P = 0.05) among strips. Strip 1 had lower yields than strip 2, which may have been due to increased cattle trafficking in this area. Both grazing methods resulted in acceptable performance. Grazing corn residue did not affect subsequent crop yields; however, strip differences in yield within strip-grazed paddocks warrant further investigation.

Grazing intensity changed the activities of nitrogen assimilation related enzymes in desert Steppe Plants

BackgroundNitrogen, as a limiting factor for net primary productivity in grassland ecosystems, is an important link in material cycles in grassland ecosystems. However, the nitrogen assimilation efficiency and mechanisms of grassland plants under grazing disturbance are still unclear. This study investigated Stipa breviflora desert steppe which had been grazed for 17 years and sampled the root system and leaf of the constructive species Stipa breviflora during the peak growing season under no grazing, light grazing, moderate grazing and heavy grazing treatments. The activities of enzymes related to nitrogen assimilation in roots and leaves were measured.ResultsCompared with no grazing, light grazing and moderate grazing significantly increased the activities of nitrate reductase (NR), glutamine synthetase (GS), glutamic oxaloacetic transaminase (GOT) and glutamic pyruvate transaminase (GPT) in leaves, and GS, GOT and GPT in roots of Stipa breviflora, while heavy grazing significantly decreased the activities of GS in leaves and NR in roots of Stipa breviflora. NR, GOT and GPT activities in leaves and roots of Stipa breviflora were positively correlated with nitrogen content, soluble protein, free amino acid and nitrate content.ConclusionsGrazing disturbance changed the activities of nitrogen assimilation related enzymes of grassland plants, and emphasized that light grazing and moderate grazing were beneficial for nitrogen assimilation by grassland plants. Therefore, establishing appropriate stocking rates is of great significance for material flows in this grassland ecosystem and for the stability and sustainable utilization of grassland resources.

Effect of grazing management strategies on alpine grassland on the northeastern Qinghai-Tibet Plateau

In recent decades, alpine grassland has been seriously degraded owing to overgrazing across the Qinghai Tibetan Plateau (QTP), although grazing exclusion has been widely adopted to restore degraded QTP grassland. It remains unknown whether such management approach is effective for all degraded alpine grasslands, and the effect of different grazing management strategies on grassland at varying levels of degradation needs to be assessed. In this study, plots with three grazing management treatments (free grazing, FG; reduced grazing, RG; grazing exclusion, GE) and four degradation stages (non-degradation, ND; light degradation, LD; moderate degradation, MD; heavy degradation, HD) were compared. Our results showed that the total aboveground biomass (AGB) and species richness (SR) under free grazing treatment were reduced with increasing degradation, whereas total belowground biomass (BGB) under free grazing treatment increased with increasing degradation. Furthermore, the responses of SR, AGB and BGB to grazing management varied with the degree of degradation. The total AGB in the LD, MD and HD stages increased significantly following RG and GE treatments, but there was no significant change of AGB in the ND stage. Meanwhile, SR reduced significantly following RG and GE treatments under all degradation stages except for HD. After RG and GE treatments, the total BGB increased significantly in the ND stage but decreased significantly under GE treatment in the MD and HD stages. Furthermore, the responses of plant functional groups to grazing management were varied. The Gramineae AGB increased significantly across all degradation levels under RG and GE treatments, whereas the sedges AGB decreased (except in the MD stage under GE management). Our results suggested that the effect of grazing management on alpine grassland depended on the degree of degradation.

Effects of Mob-Grazing on Soil and Range Quality Vary with Plant Species and Season in a Semiarid Grassland

Mob-grazing involves maintaining high densities of livestock for short periods so that most plants are either eaten or trampled, followed by long rest periods. This practice has been proposed as a mechanism to increase soil carbon (C) storage and range quality. However, mob-grazing has not universally achieved these objectives, possibly because many factors influence the effects of grazing on soil C dynamics and vegetation. This study examines factors that may mediate grazing impacts on soil C by comparing plant cover and the seasonal dynamics of roots, soil variables, and mycorrhizal fungal hyphae in experimental plots treated with traditional grazing, annual mob-grazing or no grazing for 18 yr. Root and soil variables were measured directly underneath a C4 grass, a C3 grass, and a forb up to 5 × during a 13-mo period. Mob-grazing did not influence total soil C, but it significantly increased soil organic matter (SOM), fine particulate organic matter, and nitrogen-15 (δ15N). Furthermore, mob-grazing increased soil compaction, decreased soil aggregate stability, decreased soil moisture, and tended to increase the abundance of two invasive plant species: Salsola tragus and Bromus tectorum. Soil compaction, soil aggregate stability, root biomass, particulate organic matter, and percent soil C and N varied significantly across seasons and among plant species. The density of mycorrhizal fungal hyphae varied with season but not with grazing treatment. A significant grazing by date interaction in root biomass and soil carbon-13 (δ13C) suggests that root dieback and inputs of pulverized plant material with a higher δ13C signature could be the source of higher SOM in mob-grazed plots. Compared with ungrazed plots, traditionally grazed plots had higher SOM without the adverse impacts on vegetation and soil properties observed in the mob-grazed plots. No single management strategy is universally beneficial. Range managers should carefully weigh the pros and cons of mob-grazing because, although it can increase SOM in surface soils, it may also negatively impact soil structure and composition of vegetation.

Effects of Long-Term Enclosing on Vertical Distributions of Soil Physical Properties and Nutrient Stocks in Grassland of Inner Mongolia

Enclosing plays a crucial role in vegetation and soil quality in grassland. The biomass of green plants, litter, and vertical distributions of soil physical properties and nutrient stocks were evaluated at plot enclosed long term for 38 years inside a fence and a long-term grazing plot outside a fence in a semi-arid grassland of Inner Mongolia. The results showed that dry matter of green plants and litter during the 38-year enclosing treatment was higher than in the grazing treatment (p &lt; 0.01). The soil silt (2–50 μm) in the 38-year enclosing treatment was 5.9% higher than in the grazing treatment (p &lt; 0.01) in 0–10 cm soil, and the fine sand (100–250 μm) was 6.0% lower (p &lt; 0.05). The 38-year enclosing treatment slightly decreased the bulk density and significantly decreased the electrical conductivity in each soil layer (0–100 cm). The 38-year enclosing treatment significantly increased the stocks of soil organic carbon (SOC), available phosphorus (AP), and available potassium (AK) on the surface soil, and obviously decreased the stocks of total nitrogen (TN), total phosphorus (TP), calcium (Ca), magnesium (Mg), sulfur (S), and available nitrogen (AN) in each soil layer (0–100 cm). In conclusion, long-term enclosing improved grassland production, but decreased most nutrient stocks in soil.

Control of meadowsweet Filipendula ulmaria through a change of management from grazing to mowing at an English floodplain meadow.

Floodplain meadow grassland is a diverse habitat which has become increasingly rare throughout Europe. Meadowsweet Filipendula ulmaria, is a characteristic species of its plant community, however it can become overly dominant in the sward resulting in detrimental effects on the community as a whole. High abundance can reduce both the diversity of the sward, by shading out low growing species, and the quality of the hay crop. An eight-year management trial (2011-2019) was undertaken at Fancott Woods and Meadows SSSI by the BCN Wildlife Trust and the Floodplain Meadows Partnership, to test whether it was possible to reduce the dominance of meadowsweet through an annual hay cut with aftermath grazing instead of grazing management only, across three blocks of experimental treatments. A secondary aim of the trial was to investigate whether a change in management could also increase the plant-species diversity. Three plots were cut in June and then aftermath grazed, compared to three control plots that were only grazed from July onwards. The study found that cover of meadowsweet decreased from 55% to 6% under the annual cut and aftermath grazing treatment compared to a decrease from 58% to 35% in the control (grazed only) areas. This was accompanied by an increase in plant-species diversity in the cut areas compared to control plots. The study concluded that annual cutting can be used to control coarse and dominant meadowsweet effectively, and that cutting followed by aftermath grazing in a floodplain meadow delivers greater botanical diversity compared to grazing alone.

Livestock Increase Soil Organic Carbon in the Northern Great Plains

Managing grasslands to sequester carbon is of global importance, but effects of grazing on soil organic carbon (SOC) stocks remain uncertain. We quantified effects of livestock grazing (grazed or not for 9−26 yr) and soil texture on SOC stocks (kg × m−2) of 20 sites in a temperate grassland. We also quantified the effects of livestock grazing on SOC concentration and bulk density. Percent sand explained a considerable amount of the variation in SOC stock (r2 = 0.45 to 0.59). In addition, SOC stocks were 12% less in areas rested from livestock grazing (i.e., not grazed) than annually grazed. Soil carbon concentrations were also 10% less in rested than grazed areas. Bulk density was 2% less in areas rested from grazing, but bulk density was greater at sites with longer periods of rest. We also detected a grazing treatment and rest duration interaction, indicating that bulk density differences between grazing treatments tended to be greater at sites with longer periods of rest. Compared with no grazing, moderate grazing tended to increase SOC stocks and concentrations. Although compaction (i.e., increase in bulk density) is generally regarded as an indicator of declining soil health, minor compaction may help reduce mineralization of SOC and ultimately increase SOC stocks. We discuss methodological improvements needed for a next generation of grazing land experiments to better resolve how best to manage livestock and sequester carbon.

Restricting dairy cow access time to pasture in autumn: The effects on milk production, grazing behaviour and DM intake of late lactation dairy cows

Extending the grazing season in pasture based systems of dairy production can increase farm profitability; poor weather and soil conditions can reduce the number of grazing days. The study objectives were to (i) examine the effect of restricted access to pasture in the autumn on the milk production, grazing behaviour and DM intake (DMI) of late lactation spring-calving dairy cows and (ii) establish the effect of alternating restricted and continuous access to pasture on dairy cow production, DMI and grazing behaviour. Cows were randomly assigned to one of four grazing treatments: (i) 22 h (full-time) access to pasture (22H; control); (ii) Two 5-h periods of access to pasture (2×5H); (iii) Two 3-h periods of access to pasture (2×3H); and (iv) alternating between full-time and 3-h access to pasture with no more than three continuous days on any one regime, e.g. Monday – full-time access, Tuesday − 2x3H access, Wednesday − 2x3H access; Thursday – full-time access, etc. (2×3HV). Restricted access to pasture was offered after a.m. and p.m. milking. Swards of similar quality and pregrazing herbage mass were offered. Treatment had no effect on milk yield (13.2 kg/day), milk fat (48.2 g/kg), protein (39.0 g/kg) or lactose content (42.6 g/kg) and milk solid yield (1.15 kg/day). Similarly, there was no effect of treatment on final BW (483 kg) or final BCS (2.66). There was no significant difference in DMI (15.1 kg DM/cow/day) between treatments. There was an effect on daily grazing time, 22H cows (565 min/cow/day) grazed for longest time, however, when the 2x3HV treatment had full-time access to pasture, they had a similar grazing time (543 min/cow/day) to the 22H cows and were similar to the 2x3H treatment on days with restricted access to pasture (357 min/cow/day). The 22H and 2x5H animals had similar grass DMI/min (29.2 g/min), the 2x3HV were higher (33.9 g/min) but were similar to the comparable treatment when offered 2x3H access time (41.6 g/min) and when offered 22H access time (27.7 g/min). The results from this study show how when offered a grass only diet of autumn pasture grazing behaviour can be modified by restricting pasture access time without reducing dairy cow production in late lactation at low production levels. There was also no effect of alternating access time between 22H and 2x3H on milk production and DMI in the 2x3HV treatment. Restricted access time to pasture in autumn may be a strategy which farmers can use to extend the grazing season.

Collaborative Adaptive Rangeland Management, Multipaddock Rotational Grazing, and the Story of the Regrazed Grass Plant

Frequent, severe defoliation reduces grass production and can alter plant species composition in grasslands. Multipaddock rotational grazing has been proposed as a grazing strategy that may reduce the frequency and intensity of defoliation on palatable grass plants without altering stocking rates. Previous studies evaluated this hypothesis using small, homogeneous paddocks and nonadaptive rotation schedules and found small and inconsistent differences between continuous and rotational grazing systems. Using a stakeholder-driven collaborative adaptive management (CAM) framework, we conducted the first ranch-scale experimental investigation into tiller defoliation patterns in the context of adaptive multipaddock rotational grazing. We monitored tiller defoliation frequency and intensity in 10 paired 130-ha pastures assigned to either a collaborative adaptive multipaddock rotational grazing treatment (CARM, one livestock herd) or a season-long continuous grazing treatment (traditional rangeland management [TRM]; 10 separate herds) in shortgrass steppe. Consistent with previous studies, we observed that frequencies of grazing and regrazing on a palatable, cool-season grass (western wheatgrass, Pascopyrum smithii) were much more sensitive to stocking rate than grazing system. Under moderate stocking rates used in both CARM and TRM treatments, roughly two-thirds of western wheatgrass tillers remained ungrazed annually, regardless of grazing system. Thus, season-long rest is present in season-long continuous and rotational grazing systems. Frequencies of tiller regrazing were low (5−15%) and similar between CARM and TRM treatments. Although defoliation patterns were similar between treatments at the whole-ranch scale, CARM enhanced spatial and temporal heterogeneity in defoliation frequencies among individual pastures. Pastures grazed earlier in the season or for longer experienced more defoliation. Managers implementing adaptive, multipaddock rotational grazing could use this heightened and predictable variability to strategically manage impacts of grazing on western wheatgrass at the individual pasture scale. The CAM model enabled our team to identify and directly address key stakeholder hypotheses and resulted in coproduction of management-relevant research.

Herbage accumulation and tillering dynamics of ‘Zuri’ guineagrass under rotational stocking

AbstractUnderstanding the effects of grazing management on tillering dynamics of forage grasses may help identify management practices that optimize pasture production, stability, and ultimately, persistence. The objective of this research was to evaluate the effects of two grazing frequencies (regrowth interrupted when the canopy was 70 cm tall or at 95% canopy light interception [LI]) and two grazing intensities (reduction of 29 [lenient] or 57% [standard] of initial canopy height) in ‘BRS Zuri’ guineagrass [Megathyrsus maximus (Jacq.) B.K. Simon &amp; S. W. L Jacobs (syn. Panicum maximum Jacq.)], under rotational stocking and on herbage accumulation rate (HAR), tiller appearance rate, tiller mortality, tiller survival rate, tiller stability index (SI), tiller population density (TPD), tiller mass (TM), apical meristem height, and tiller half‐life during two summer rainy seasons in Piracicaba, Brazil. The experimental design was randomized complete block, with a 2 × 2 factorial arrangement. The HAR was not affected by treatments in the first year, averaging 100 kg dry matter ha−1 d−1, but was greater under lenient than standard grazing (146 and 81 kg dry matter ha−1 d−1, respectively) in the second year. In both years, there were no treatment effects on TPD and TM. The use of 95% LI associated with standard defoliation increased the variability in SI. Great tiller population renewal indicated by short tiller half‐life, varying from 31 to 75 d, classifies Zuri as an exploitative cultivar. Zuri guineagrass maintained tiller SI under the grazing treatments imposed but had greater HAR under lenient grazing.

Single Grazing Is More Detrimental to Grasslands Than Mixed Grazing: Evidence From the Response of Functional Traits of Dominant Plants to Grazing Systems

Plant functional traits reflect species ecological strategies and determine how plants respond to environmental changes, however, how dominant species in the Inner Mongolia grassland adapt to different grazing systems by changing their functional traits has not been systematically investigated. In this study, we established four 7-year grazing treatments in the Inner Mongolia grassland: cattle grazing, sheep grazing, mixed sheep and cattle grazing, and no grazing. Fourteen functional traits of three dominant species (Stipa grandis, Leymus chinensis, and Cleistogenes squarrosa) were measured under the different grazing treatments. We found convergences of plant functional traits that indicate herbivory avoidance or tolerance. Plants reduced their vegetative height (VH) and stem: leaf ratio (SLR) to avoid grazing; increased their ability to acquire resources by increasing their specific leaf area (SLA), leaf nitrogen concentration (LNC), and leaf phosphorus concentration (LPC); and reduced their leaf dry matter content (LDMC) to tolerate grazing. Moreover, plants may adapt to grazing by increasing the intraspecific variability of their functional traits. Sheep-only grazing adversely affected L. chinensis growth and survival, while cattle-only grazing hindered S. grandis growth and increased the intraspecific variability of its plant functional traits. Our study emphasizes that intraspecific variability is an important indicator of the responses of plant functional traits to grazing. Since single grazing is more detrimental to the functional traits of dominant plants, we suggest that mixed cattle and sheep grazing may be a more environmentally friendly and sustainable practice for the Inner Mongolia grassland than single grazing.

Co-culture with grazers can improve survival and growth of multiple coral species

High post-settlement mortality in ex situ sexually propagated coral recruits remains a significant bottleneck to production of corals for reef restoration, scientific experiments and the ornamental trade. Co-culture with grazing herbivores represents a potentially cost-effective method to reduce recruit competition with algae, thus improving the survival and yield of corals. Here we examined the effectiveness of co-culture of coral recruits of Acropora millepora, A. tenuis, A. secale, Porites lobata and Platygyra daedalea with herbivorous gastropods, Calthalotia strigata and Turbo haynesi, and herbivorous juveniles of the Asteroid Acanthaster cf. solaris. Coral recruits (200 per species) were settled onto individual aragonite plugs, with 10 plugs per species introduced to twenty 50 L experimental tanks. Each tank was randomly assigned to one of five grazing treatments; (1) Thalotia, 30 C. strigata per tank, (2) Turbo, 30 T. haynesi per tank, (3) CoTS, 30 A. cf. solaris per tank, (4) Mix, 10 C. strigata, 10 T. haynesi and 20 A. cf. solaris per tank, and (5) Control, no grazers added. We found that over a 2-month period single species co-culture with C. strigata significantly improved the survival of A. millepora, A. tenuis, A. secale and P. lobata, whilst P. daedalea benefitted most from co-culture with T. haynesi. Over 6-months, C. strigata produced the highest survival in A. millepora (51.6% ± 5.24%), A. tenuis (46.6% ± 3.16%) and A. secale (38.5% ± 3.48%), but T. haynesi co-culture resulted in higher survival in P. lobata (67.3% ± 3.76%) and P. daedalea (100% ± 0%). These results were all significantly higher than the survival of corals in controls, which after 6 months averaged ~1.87% for the Acropora species, 43.0% ± 4.79% and 57.6% ± 8.60% for P. lobata and P. daedalea respectively. Increase in basal surface area of recruits was varied, with the highest relative increases in recruit basal disk area occurring in Thalotia treatments for A. millepora and A. secale, in Turbo for A. tenuis, and in the Control tanks for P. lobata and P. daedalea. This study provides strong evidence that co-culture with C. strigata can improve ex situ sexual coral propagation, with minimal additional intervention from aquarists. The large increase (23.6× higher) in survival of ecologically and economically important coral species such as A. millepora demonstrates the potential of co-culture to enhance ex situ coral propagation.

Effects of short-term grazing prohibition on soil physical and chemical properties of meadows in Southwest China.

BackgroundGrassland plays an important role in the ecosystem, but overgrazing harms the grassland system in many places. Grazing prohibition is an effective method to restore grassland ecosystems, and it plays a great role in realizing the sustainable development of grassland systems. Therefore, it is necessary to carry out research on the influence of regional grazing prohibition on the physical and chemical properties of different grassland systems.MethodsIn Potatso National Park, Southwest China, we selected experimental plots in the artificial grazing meadow area to study the effects of grazing prohibition on plant and soil indexes in subalpine meadows and swamp meadows. We investigated the biomass and species diversity of grazing prohibition treatment and grazing treatment plots and sampled and tested the soil index. The variation percentage was used to remove the original heterogeneity and yearly variation, allowing us to compare differences in plant index and soil index values between grazing prohibition and grazing treatments.ResultsGrazing prohibition increased the aboveground biomass, total biomass, total meadow coverage, average height, richness index, Shannon diversity index and evenness index and reduced the belowground biomass and root/shoot ratio in the subalpine meadow and swamp meadow. Additionally, grazing prohibition reduced the pH and soil bulk density and increased the soil total carbon, soil organic carbon, soil total nitrogen, soil hydrolyzable nitrogen, soil total phosphorus and soil available phosphorus in the subalpine meadow and swamp meadow. Nonmetric multidimensional scaling (NMDS) analysis showed that both plant indexes and soil indexes were significantly different between grazing and grazing prohibition treatments and between meadow types. Short-term grazing prohibition had a great impact on improving the fertility of meadow soil in the study area. We suggest that long-term and extensive research should be carried out to promote the restoration and sustainable development of regional grassland systems.

Cattle grazing mitigates the negative impacts of nitrogen addition on soil nematode communities

Livestock grazing and atmospheric nitrogen (N) deposition have been reported as important factors affecting soil communities. However, how different large herbivore grazing and N addition may interact to affect soil biota in grassland ecosystems is unclear. Nematodes are the most abundant metazoan in soil ecosystems, play critical roles in regulating carbon and nutrient dynamics, and are valuable bioindicators. We examined the independent and interactive effects of grazing regimes (no grazing; sheep grazing; cattle grazing; mixed grazing of sheep and cattle) and N addition (ambient N; N addition) on soil nematodes in a meadow steppe. We found that grazing and N addition interacted to influence total nematode abundance, trophic group abundance, generic richness, diversity and several nematode-based indices (maturity index, channel ratio, enrichment index). In cattle grazing treatment, N addition significantly increased total nematode abundance, and the abundance of bacterial feeders, plant feeders, and omnivore-predators, and generic richness. By contrast, in the sheep and mixed grazing treatments, N addition had a negative effect on the same variables. Moreover, N addition reduced nematode maturity, enrichment and structure indices, and enhanced nematode channel ratio, in most grazing treatments, except mixed grazing where N addition had no effect on these variables. Structural equation modeling (SEM) revealed that N addition indirectly reduced nematode abundance and richness through increased soil NO3−-N content, whereas the effects of grazing were associated with increased relative biomass of grasses. Our results suggested that the response of soil nematodes to N addition strongly depended on herbivore assemblages. Nitrogen addition enhanced soil nematode diversity and maintained a relatively complex and mature soil food web in the presence of cattle rather than sheep grazing. Furthermore, our study highlighted that under N deposition, cattle grazing could benefit the soil nematode community.

Comparative impacts of grazing and mowing on the floristics of grasslands in the buffer zone of Polesie National Park, eastern Poland

Most European grasslands are semi-natural and require proper management to preserve their high natural value. They are habitats for many rare and endangered species of plants and animals. The aim of the study was to determine patterns of changes in the flora of grasslands induced by the introduction of extensive mowing and grazing treatments and to answer the following questions: (1) Do species richness and the number and occurrence of ecological groups plants differ depending on management schemes? (2) Is grazing or mowing more beneficial for the conservation of plant diversity? (3) Is the duration of land management a determinant of flora characteristics? The study was carried out in permanent grasslands located in the buffer zone of Polesie National Park in 2015–2018. The flora comprised 189 vascular plant species representing six ecological groups. The most numerous groups were meadow species (M) – 85, grassland species (G) – 35, and segetal species (S) – 31. Trees and shrubs (T) – 10 made up the smallest share of the flora, followed by ruderal (R) – 13 and aquatic (W) – 17 vegetation. The study showed that extensive grazing and mowing induced quantitative and qualitative changes in the flora of the research plots and were the key determinants of the flora dynamics. The first two years of use were crucial for the dynamics of the flora present in the plots. During that time a significant increase in species richness and the emergence of ecological groups was noted. Stabilization of the features analysed was noted in subsequent years. Significant differences were noted in species richness (SR) and the number of meadow (M), grassland (G), segetal (S), ruderal (R), water (W) and tree and shrub (T) species in favour of the managed plots compared with the abandoned sites. Grazing significantly decreased the number of emerging trees and shrubs, while mowing facilitated the preservation and regeneration of water and waterside vegetation. The use of local cattle breeds for grazing in valuable nature areas protects meadow habitats, prevents succession of trees and shrubs, and preserves and protects farm animal genetic resources.

Responses of the spatial distribution of Stipa breviflora to stocking rate at different scales.

We conducted an experiment to test the characteristics and differences of the spatial distribution of constructive species Stipa breviflora at different scales under different stocking rates in the S. breviflora desert steppe in Siziwang Banner, Inner Mongolia. The spatial distribution of S. breviflora under four treatments (control, light grazing, moderate grazing, and heavy grazing) at different scales (small scale as 1 m×1 m and mesoscale as 5 m×10 m) were analyzed. The results showed that the population density of S. breviflora at mesoscale in the control and light grazing was significantly lower than that at the small scale. Grazing significantly increased the population density of S. breviflora in the meso- and small scales. At the small scale, the population distribution of S. breviflora in the control, light grazing, moderate grazing, and heavy grazing treatments conformed to linear, exponential, exponential and exponential models, respectively, and Gaussian, exponential, Gaussian and exponential models at mesoscale fitted by semi-variance function. The spatial distribution pattern at small scales in the control was simple and better but was more complex and poorer under the heavy grazing. At the mesoscale, it was simple and better under the heavy grazing but complex and poor under the moderate grazing. The spatial heterogeneity of S. breviflora population reduced and were more uniform under the moderate and heavy grazing at meso- and small scales. In addition, the trend of population distribution in the enclosure, moderate and heavy grazing were generally the same, while light grazing showed inconsistent trend at different scales.

Intense winter grazing impairs subsequent Italian ryegrass re‐establishment in soybean‐pasture rotations

AbstractWe evaluated Italian ryegrass (Lolium multiflorum Lam.) establishment in a factorial of grazing intensity (intense, moderate, moderate‐light, light, and no grazing, with target average sward heights of 10, 20, 30, and 40 cm in the grazed plots) and additional seeding (self‐seeding with or without additional seeding) in an integrated soybean‐beef cattle system in southern Brazil. Grazing treatments were imposed in winter (June–July) and followed by a direct‐seeded soybean crop (November). The establishment was quantified prior to the stocking periods in 2017 and 2018, corresponding to self‐seeding from 2016 and 2017. Intense grazing impaired ryegrass re‐establishment, resulting in larger individual plants (0.54 vs. 0.15 g dry matter plant−1) but lower population density (57 vs. 1,355 plants m−2) than in the other treatments. Additional broadcast ryegrass seeding did not fully compensate for the reduced natural reseeding in this treatment. The addition of seeds under intense grazing increased plant population density to values comparable to moderate grazing intensities but reduced individual plant mass, limiting herbage mass attained by the end of the pasture establishment phase. Contrastingly, the various combinations of individual plant mass and population density were sufficient to maintain herbage masses in moderate to light grazing intensities that were comparable to that in the ungrazed treatment, regardless of seed addition (63 vs. 180 g DM m−2 for intense grazing vs. the average of other treatments over the whole establishment phase). Moderate grazing, e.g., target sward heights of 20 cm or greater, is necessary to achieve a system that can sustain itself without seed addition.

Grazing rest versus no grazing stimulates soil inorganic N turnover in the alpine grasslands of the Qinghai-Tibet plateau

Little information is available on soil N cycling in the grasslands of the Qinghai-Tibet plateau under different grazing regimes, which is required to evaluate management practices with respect to soil N availability and dynamics. In this study, a 15N-labeled (15NH4NO3 and NH415NO3) incubation experiment was conducted to investigate gross N transformation rates in soils of the southeast region of the Qinghai-Tibet plateau (China) under no grazing, continuous grazing and grazing rest conditions. Compared with no grazing, continuous grazing significantly reduced the rates of mineralization, microbial NH4+ immobilization, autotrophic nitrification and NO3− consumption, but increased the ratio of autotrophic nitrification to microbial NH4+ immobilization and the ratio of the rates of total NO3− production to total NO3− consumption. This indicated that continuous grazing greatly decreased both the inorganic N supply capacity and N turnover but increased the NO3− production potential of the soil. By contrast, mineralization and microbial NH4+ immobilization rates did not significantly differ in the soils of the grazing rest and no grazing treatments, suggesting that a higher soil inorganic N supply capacity is maintained by grazing rest than by continuous grazing. In addition, grazing rest stimulated NO3− turnover, by increasing the rates of autotrophic nitrification, microbial NO3− immobilization and dissimilatory NO3− reduction to NH4+. Taken together, our study suggests that the most effective management practice for the sustainable utilization of local grasslands is a regime based on grazing rest, as it improved physicochemical and biological properties, which in turn increases N supply and N turnover.

Restoration of Degraded Alpine Meadows Improves Pollination Network Robustness and Function in the Tibetan Plateau

Ecological restoration is widely used to mitigate the negative impacts of anthropogenic activities. There is an increasing demand to identify suitable restoration management strategies for specific habitat and disturbance types to restore interactions between organisms of degraded habitats, such as pollination. In the Tibetan Plateau, alpine meadows have suffered severe degradation due to overgrazing and climate change. Protecting vegetation by fencing during the growing season is a widely applied management regime for restoration of degraded grasslands in this region. Here, we investigated the effect of this restoration strategy on plant–pollinator communities and plant reproduction in the eastern Tibetan Plateau. We collected interaction and seed set data monthly across three grazed (grazed all year) and three ungrazed (fenced during growing season) alpine meadows in growing seasons of two consecutive years. We found ungrazed meadows produced more flowers and attracted more pollinator visits. Many common network metrics, such as nestedness, connectance, network specialization, and modularity, did not differ between grazing treatments. However, plants in ungrazed meadows were more robust to secondary species extinction than those in grazed meadows. The observed changes in the networks corresponded with higher seed set of plants that rely on pollinators for reproduction. Our results indicate that protection from grazing in growing seasons improves pollination network stability and function and thus is a viable restoration approach for degraded meadows.

Strip-grazing: Reduces pony dry matter intakes and changes in bodyweight and morphometrics.

Obesity can negatively impact upon equine welfare and bodyweight (BW) of pastured equines is often difficult to manage. To compare the effects of three restricted grazing regimens on changes in pony BW and morphometric measurements. Randomised study. Twelve mature ponies were individually grazed in 10m wide, rectangular, electric fenced paddocks. The dry matter (DM) herbage yield of each paddock was determined, and paddock length adjusted on Day 1 to provide 1.5% of individual pony BW as herbage DM daily, for 28days. There were four ponies per treatment. Treatments were: total paddock area (TA) and strip grazing treatments, SG1 and SG2. SG1 had a 'lead' fence spanning the paddock width being moved a set distance along the paddock length daily to provide 1.5% of pony BW as fresh pasture DM (as determined on Day -1). SG2 also had a 'back fence' 7-12m behind the 'lead' fence which was moved the same distance as the lead fence daily. Calculated dry matter intakes, changes in cresty neck score (CNS), body condition score (BCS) and percentage changes in BW, heart girth (HG), belly girth (BG) and rump width (RW) were compared between treatments. Mean (±SD) calculated pasture DM intakes (as % BW/d) by TA ponies were 2.33±0.50, being significantly higher (P< 0.05) than 1.82±0.43 (SG1) and 1.59±0.42 (SG2). Mean percentage BW changes were higher (P<0.05) for TA ponies at 4.82±1.36 vs. 1.16±0.39 (SG1) and 1.54±1.35 (SG2). SG1 and SG2 pony BW changes were not significantly different. TA, but not SG1 or SG2 animals showed significant (P<0.05) increases in BCS1/9 (+0.94±0.32), CNS1/5 (+0.5±0), RW (+2.11±3.6) and BG (+4.15±2.29). SG1 and SG2 ponies showed significant (P<0.05) decreases in HG (-0.05±2.12) and BG (-5.53±4.89) respectively. Small sample size. Strip grazing limited pony bodyweight gains and upward changes in morphometric parameters.