Artificial Pastures Research Articles

Heavy metal changes related to land use changes in a karst area: a case study in Changshun, Guizhou Province, China

Karst areas are often characterized by fragile ecological systems, and environmental pollution has increased the pressures on people living in such regions. This study aimed to investigate the status of pollution caused by heavy metals (Pb, Cd, Hg, As, and Cu) in soils based on different land uses in Changshun County, a karst area in southwestern China. Soil samples were collected from natural forestlands (NFLs), natural brush lands (NBLs), natural pasture lands (NPLs), artificial forestlands (AFLs), artificial brush lands (ABLs), and artificial pasture lands (APLs) for evaluation. The results suggest that the soil profile characteristics of the heavy metals studied herein vary significantly among different land uses. The heavy metal concentrations in all soil samples collected from NFLs were lower than those in samples from other land uses. Forest trees can protect soil from heavy metal pollution caused by atmospheric deposition; this is especially true for Hg. In cultivated forestlands and brush lands, special attention should be devoted to Cd pollution in the soil, which may be caused by the use of fertilizers. Changing both natural and artificial pastoral lands to forestlands could benefit the local ecosystems as it may reduce Hg contamination.

Chronological dynamics of the gut microbiome in response to the pasture grazing system in geese.

It is commonly accepted that dietary fibers are good for gut health. The effect of fibers on the diversity and metabolic activities of the cecal microflora, however, differ with the passage of time. Therefore, we investigated the time-series impacts of the pasture grazing system (a high dietary fiber source) on the cecal microbiome and short-chain fatty acids in Wanpu geese, comparing it to commercial feeding (a low dietary fiber source). The cecal microbiota composition and SCFA concentrations were evaluated by 16S rRNA gene sequencing and gas chromatography, respectively. We found that pasture produced a generally quick positive response to Bacteroidales, Lactobacillales, Gastranaerophilales (at 45 days), Lachnospirales, and Oscillospirales (at 60 days and 90 days) irrespective of Erysipelotrichales (at 45 days), Clostridia_UCG-014, RF39 (at 60 days), Christensenellales, and Peptostreptococcales-Tissierellales (at 90 days) in geese. Meanwhile, we found that Lactobacillales, Gastranaerophilales, Lachnospirales, and Oscillospirales were significantly correlated with short-chain fatty acids in pasture grazing geese. Indeed, the correlation of cecal microbiota with SCFAs led to altered microbial functions evinced by COG; KEGG pathway levels 1, 2, and 3; BugBase; and FAPROTAX databases. This study emphasizes the importance of dietary fiber sources in influencing beneficial impacts in regulating geese microbiota homeostasis and metabolic functions such as energy and lipid metabolism.IMPORTANCELow dietary fiber diet sources cause gut microbial and short-chain fatty acid alterations that lead to compromised animal health. The establishment of an artificial pasture grazing system at the expense of ryegrass is a good source of dietary fiber for geese. Our results described the importance of pasture in maintaining the gut microbiota, SCFAs, and potential microbial functions reported by COG; KEGG pathway levels 1, 2, and 3; BugBase; and FAPROTAX databases.

Integrated transcriptome and metabolome profiles reveal the regulatory molecular mechanisms of meat quality in pasture-fed goose

Goose meat is rich in amino acids with unique taste and aroma traits that are targeted by housing and feeding systems. This study aimed to investigate the impacts of in-house feeding (IHF) and artificial pasture grazing (AGF) systems on nutrient composition, flavor, and taste of thigh muscles of goose. The proximate analysis showed that, compared to IHF group, AGF group contained significantly higher contents of moisture and crude protein than ash and intramuscular fat. The findings of transcriptome analysis revealed that 139 differentially expressed genes (DEGs) displayed differential expression (102 genes downregulated and 37 genes upregulated), and only 13 DEGs were involved in fatty acid metabolic process, protein binding, and calcium ion binding. Together, 79 and 16 significantly differential metabolites (SDMs) were identified through LC-MS/MS and GC-TOF-MS, respectively. Furthermore, we performed KEGG enrichment analysis of DEGs and related them with enriched signaling pathways attained from SDMs. Collectively, we detected 4 common KEGG pathways involved in the development of flavor and taste in AGF geese, namely sphingolipid metabolism, arginine and proline metabolism, alanine, aspartate and glutamate metabolism, and valine, leucine and isoleucine degradation. In these pathways, the upregulated uridine diphosphate (UDP)-glycosyltransferase 8 (UGT8), glycine amidinotransferase (GATM), and aldehyde dehydrogenase (ALDH) and downregulated ceramide synthase 6 (CERS6) genes may regulate the synthesis of metabolites including l-serine, phosphatidylethanolamine, l-arginine, l-glutamate, lysyl-proline, d-ornithine, putrescine, and alpha-ketoisocaproic acid 2 in pasture-fed group. These genes and metabolites may play a key role in regulating protein accumulation, IMF deposition, meat flavor, and taste development in pasture-fed group.

Effects of nitrogen fertilization rate and seeding density on the forage yield and quality of autumn‐sown triticale in an alpine grazing area of the Qinghai‐Tibetan Plateau, China

Abstract‘Gannong No. 2’ triticale (×Triticosecale Wittmack) is a cold‐resistant annual forage crop variety, which can be planted as artificial pasture to solve the problem of forage shortage in the Gannan alpine grazing area of the Qinghai‐Tibetan Plateau. However, the optimal nitrogen fertilization rate and seeding density for obtaining high yield and quality forage are still unknown. In this study, the effects of nitrogen fertilization rate and seeding density on the forage yield and quality of autumn‐sown ‘Gannong No. 2’ triticale were studied. We used a split‐plot design, with five nitrogen fertilization rates assigned to the main plots, namely 0 (A1), 120 (A2), 240 (A3), 360 (A4), and 480 kg N ha−1 (A5), and five seeding densities assigned to subplots: 506 × 104 (B1), 675 × 104 (B2), 843 × 104 (B3), 1011 × 104 (B4), and 1180 × 104 seeds ha−1 (B5). Significant differences in lodging rate, tiller number, hay yield, crude protein content, neutral detergent fibre, and relative feed value were observed at different fertilization levels. Significant differences were found in lodging rate, plant height, tiller number, hay yield, contents of neutral detergent fibre and acid detergent fibre, dry matter digestibility, and relative feed value among the seeding density treatments. The interaction of nitrogen fertilization rate and seeding density significantly affected forage yield and quality, with the A3B3 treatment having the highest comprehensive evaluation value. In alpine grazing areas of the Qinghai‐Tibetan Plateau, 240 kg N ha−1 and 843 × 104 seeds ha−1 should therefore be used for autumn‐sown triticale.

Comparisons of the Grazing Type Population with Hay-Type Cultivars of Alfalfa (Medicago sativa L.) and Determination of Their Yield-Related Characteristics under Rainfed Conditions

Alfalfa (Medicago sativa L.) is one of the most important forage legume crops for increasing the quantity and quality of degraded rangelands. Although rangelands in Türkiye have a great diversity of species in terms of vegetation composition, no cultivar has been developed for grassland rehabilitation. For this reason, improvement for grazing type cultivars is one of the priorities of alfalfa breeding studies. In this alfalfa study, the advanced grazing type population (L-1739), and hay type cultivars (Bilensoy-80, Savaş, Gözlü, and Plato) were evaluated for agro-morphological, and quality traits under the rainfed condition in 2012-2014 and compared in terms of the measured traits. The L-1739 had the highest number of stems, with 22.54 stems per plant in two years. However, the hay-type cultivars had a higher plant height and stem diameter than L-1739. In addition, it produced similar quality but had a lower forage yield. The general yields were 4.46 and 1.37 t ha-1 for green and dry forage, respectively, as a two-year mean. The quality traits of all genotypes tested in the study were similar. As a result, the L-1739 should be used for rangeland rehabilitation by over-seeding and hay-type cultivars (except Gözlü) may be used for establishing artificial pasture on cropland under rainfed conditions. Moreover, hay yield was found to be strongly correlated with plant height and stem diameter. Similar traits and their degree of similarity were determined by the method of cluster analysis.

A RESEARCH ON THE HAY YIELD AND QUALITY OF ALFALFA CULTIVARS WITH DIFFERENT FALL DORMANCY RATES UNDER MEDITERRANEAN CLIMATE CONDITIONS

This research was carried out as two separate trials established in two different years to determine the effects
 of different seed ratios and harvest stages of different annual companion crop species on the hay yield and
 botanical composition of a pasture mixture under Mediterranean climate conditions. The field trials were
 established in a randomized complete block with a split-plot arrangement in three replications. The research
 results showed that barley, annual ryegrass, and berseem clover can be utilized as companion crops in
 artificial pasture systems. The inclusion of these companion crop species in the pasture mixture resulted in an
 increase in forage yield and a significant decrease in weed infestation. While delaying the harvest stage of the
 companion crop does not have a notable effect on the proportion of legumes and weeds in the total biomass, it
 significantly enhances the dry forage yield and the proportion of grasses in the overall biomass of the mixture.

EFFECTS OF COMPANION CROP ON THE HAY YIELD AND BOTANICAL COMPOSITION OF PASTURE UNDER MEDITERRANEAN CLIMATE CONDITIONS

This research was carried out as two separate trials established in two different years to determine the effects of different seed ratios and harvest times of different annual companion crop species on the hay yield and botanical composition of a pasture mixture under Mediterranean climate conditions. The field trials were established in a randomized complete block with a split-plot arrangement in three replications. The research results showed that barley, annual ryegrass, and berseem clover can be utilized as companion crops in artificial pasture systems. The inclusion of these companion crop species in the pasture mixture resulted in an increase in forage yield and a significant decrease in weed infestation. While delaying the harvest time of the companion crop does not have a notable effect on the proportion of legumes and weeds in the total biomass, it significantly enhances the dry forage yield and the proportion of grasses in the overall biomass of the mixture.

MORPHOLOGICAL, AGRONOMIC, AND QUALITY PROPERTIES OF THE TWO DEVELOPED POPULATIONS OF ALFALFA (Medicago sativa L.) UNDER NON-IRRIGATED CONDITIONS OF SEMIARID REGIONS

Alfalfa is the most important crop in Turkey but there is no alfalfa cultivar developed for rainfed conditions under the semiarid regions in Turkey. For this reason, new cultivars are needed for using of rangeland improvement, artificial pasture establishment, and hay production. For this reason, the two alfalfa populations were developed by the mass selection method in the breeding project. These two advanced populations (L-533, and L-1739) were examined with the three control cultivars of alfalfa (Bilensoy-80, Savaş and Kayseri) for morphological, yield and quality traits in two various regions of Turkey in three experimental years. The present study results demonstrated that there were significant differences in terms of the plant height, but no differences in stem diameter, and stem number among the study genotypes. When evaluating all genotypes, the L-533 and Kayseri had the highest yield value, but the Savaş cultivar was the lowest. As compared to Bilensoy-80 cultivar, the L-533, and L-1739 populations gave higher at 22.27 and 11.57% in green forage yield; 18.30 and 10.13% in dry forage yields, respectively.
 In addition, statistically significant differences were found for ADF, NDF, and digestible dry matter yield among the study genotypes, except crude protein contents. Moreover, the highest crude protein content and digestible dry matter yield were obtained from the L-533 and L-1739, but the L-533 had also the lowest NDF content. The present study result showed that the L-533, and L-1739 had high adaptation capability, excellent yield, and good quality performance in dry conditions under semi-arid regions and could be used as commercial cultivars.

Bird species responses to rangeland management in relation to their traits: Rio de la Plata Grasslands as a case study.

Areas used for livestock production and dominated by native grasses represent a unique opportunity to reconcile biodiversity conservation and livestock production. However, limited knowledge of individual species' responses to rangeland management restricts our capacity to design grazing practices that favor endangered species and other priority birds. In this work, we applied Hierarchical Modelling of Species Communities (HMSC) to study individual species responses, as well as the influence of traits on such responses, to variables related to rangeland management using birds of the Rio de la Plata Grasslands as a case study. Based on presence-absence data collected in 454 paddocks across 46 ranches we inferred the response of 69 species considering imperfect detection. This degree of detail fills a major gap in rangeland management, as species-level responses can be used to achieve targeted conservation goals other than maximizing richness or abundance. We found that artificial pastures had an overall negative impact on many bird species, whereas the presence of tussocks had a positive effect, including all threatened species. Grassland specialists were in general sensitive to grass height and tended to respond positively to tussocks but negatively to tree cover. Controlling grass height via adjustments in stocking rate can be a useful tool to favor grassland specialists. To favor a wide range of bird species in ranches, a mosaic of short and tall native grasslands with patches of tussocks and trees is desirable. We also found that species-specific responses were modulated by their traits: small-sized birds responded positively to tussocks and tree cover while large species responded negatively to increasing grass height. Ground foragers preferred short grass while birds that scarcely use this stratum were not affected by grass height. Results on the influence of traits on bird responses are an important novelty in relation to previous work in rangelands and potentially increase our predicting capacity and model transferability across grassland regions.

Stall-Feeding of Sheep on Restricted Grazing: Effects on Performance and Serum Metabolites, Ruminal Fermentation, and Fecal Microbiota.

This study investigated the effects of three feeding systems, indoor feeding (CONT), indoor feeding with time-restricted grazing artificial pasture (4 h/day, G4H), and indoor feeding with an eight-hour daily grazing artificial pasture (G8H), on the growth performance, serum metabolites, ruminal fermentation, and fecal microbiota composition of lambs. Average daily gain showed a tendency (p = 0.081) to be higher for the G4H group compared with the CONT group. Moreover, feeding systems did not have a significant effect on most of the serum biochemical indicators in lambs. Concentrations of serum glutathione peroxidase and immunoglobulins (IgA, gG, and IgM) were significantly lower (p < 0.01) in the CONT group. Additionally, a tendency towards higher levels of volatile fatty acids, acetate, and butyrate was found in animals of the G4H group compared to the CONT group. Furthermore, fecal microbiota composition was altered in G4H and G8H groups, resulting in the increased relative abundance of Firmicutes and Ruminococcaceae UCG-005, as well as the decreased relative abundance of Ruminobacter compared with the CONT group. Overall, these results suggest that indoor feeding with restricted grazing time does not significantly affect fattening performance or rumen fermentation but enhances antioxidation and immune function activity and also alters fecal microbiota composition.

Trade-offs between passive and trophic rewilding for biodiversity and ecosystem functioning

Trophic rewilding that reintroduces large animals into landscapes to re-establish food web interactions and restore biodiverse ecosystems has gained widespread attention. Despite this attention, few empirical studies have assessed the effectiveness of trophic rewilding for promoting biodiversity and its wider ecological benefits. Here we tested if trophic rewilding that introduced functional analogues for extinct large herbivores into former farmland of lowland England delivered additional benefits to biodiversity and ecosystems functioning. We predicted that these benefits would exceed those achieved through passive rewilding, that is, unassisted habitat succession after the cessation of agricultural activity. Using a 9-year exclosure experiment, we found trophic rewilding reduced woody plant diversity and total carbon storage by 73% and 23%, respectively, compared to passive rewilding plots that excluded mammalian herbivores. However, trophic rewilding likely increased plant diversity and carbon storage compared to if land was left under continued agricultural production, e.g. artificial pastures associated with intensive livestock production. The vegetation changes accompanying trophic rewilding were further linked to a greater diversity and biomass of ground-dwelling arthropods by 21% and 167%, respectively, relative to passive rewilding, partly by creating more structurally complex vegetation. Given the trade-offs in biodiversity and ecosystem functions between trophic and passive rewilding, our study highlights that trophic rewilding will need to be applied alongside other interventions to tackle biodiversity loss while combatting climate change. Ultimately, the utility of trophic rewilding as a restoration tool will depend on the conservation outcomes valued by society.

Pasture intake protects against commercial diet-induced lipopolysaccharide production facilitated by gut microbiota through activating intestinal alkaline phosphatase enzyme in meat geese.

Diet strongly affects gut microbiota composition, and gut bacteria can influence the intestinal barrier functions and systemic inflammation through metabolic endotoxemia. In-house feeding system (IHF, a low dietary fiber source) may cause altered cecal microbiota composition and inflammatory responses in meat geese via increased endotoxemia (lipopolysaccharides) with reduced intestinal alkaline phosphatase (ALP) production. The effects of artificial pasture grazing system (AGF, a high dietary fiber source) on modulating gut microbiota architecture and gut barrier functions have not been investigated in meat geese. Therefore, this study aimed to investigate whether intestinal ALP could play a critical role in attenuating reactive oxygen species (ROS) generation and ROS facilitating NF-κB pathway-induced systemic inflammation in meat geese. The impacts of IHF and AGF systems on gut microbial composition via 16 sRNA sequencing were assessed in meat geese. The host markers analysis through protein expression of serum and cecal tissues, hematoxylin and eosin (H&E) staining, localization of NF-қB and Nrf2 by immunofluorescence analysis, western blotting analysis of ALP, and quantitative PCR of cecal tissues was evaluated. In the gut microbiota analysis, meat geese supplemented with pasture showed a significant increase in commensal microbial richness and diversity compared to IHF meat geese demonstrating the antimicrobial, antioxidant, and anti-inflammatory ability of the AGF system. A significant increase in intestinal ALP-induced Nrf2 signaling pathway was confirmed representing LPS dephosphorylation mediated TLR4/MyD88 induced ROS reduction mechanisms in AGF meat geese. Further, the correlation analysis of top 44 host markers with gut microbiota showed that artificial pasture intake protected gut barrier functions via reducing ROS-mediated NF-κB pathway-induced gut permeability, systemic inflammation, and aging phenotypes. In conclusion, the intestinal ALP functions to regulate gut microbial homeostasis and barrier function appear to inhibit pro-inflammatory cytokines by reducing LPS-induced ROS production in AGF meat geese. The AGF system may represent a novel therapy to counteract the chronic inflammatory state leading to low dietary fiber-related diseases in animals.

Amphibian richness along modified riparian areas of central Mexico: conservation priorities

BackgroundLand-use change frequently affects faunistic populations and communities. To achieve successful conservation strategies, we need suitable information about species distribution and the causes of extinction risk. Many amphibian species depend on riparian vegetation to complete their life cycles. About 41% of amphibian species are globally threatened, and accurate estimations of population size, species richness and the identification of critical habitats are urgently needed worldwide. To evaluate the magnitude of changes in species richness and demography, estimations that include detection probability are necessary. In this study, we employed multi-species occupancy models to estimate detection probability and the effect of land cover type (i.e., cropland, artificial pasture, secondary and mature forest) in a 500-m radius on the occupancy probability and richness of diurnal amphibians in 60 riparian zones in the state of Michoacán in central Mexico. Furthermore, we evaluated the potential of the endemic salamander Ambystoma ordinarium as a flagship species for the conservation of other native amphibian species.ResultsWe registered a total of 20 amphibian species in the diurnal assemblage, of which 10 species are considered at risk of extinction. We found that cropland was the most important land-use type for explaining amphibian distribution in riparian zones, with negative effects on most amphibian species. We found no differences in species richness between zones with and without A. ordinarium. In riparian zones occupied by A. ordinarium, however, we found a higher number of species at risk of extinction.ConclusionsOur findings showed negative effects of croplands on the distribution of most amphibian species. The riparian zones are important for the maintenance of native diurnal amphibian communities and A. ordinarium can act as a flagship species for the conservation of threatened amphibian species.

Reciprocity of grassland conservation and pastoralist livelihoods: Evidence from comparison between developed and developing regions

Grasslands provide important livestock products such as beef and milk, the main source of daily nutrients for human beings. However, ecological degradation has occurred in nearly 50% of global grasslands, which seriously restricts livestock product supply and impairs human well-beings. Sustainable management measures are explored both in developed and developing regions to curb grassland degradation trend and achieve economic-ecological coordination. We focused on the differences of grassland management measures and their economic-ecological effects between developed regions (US, New Zealand and Western Europe) and developing regions (Inner Mongolia, China) along the “global gold pastures” in middle-latitude zone, by analyzing human-induced grassland productivity changes based on satellite remote sensing, and livestock carrying pressure based on forage-livestock relationship. The results showed the human-induced GPP on grasslands were higher in those developed regions than Inner Mongolia, while the livestock carrying pressures of grasslands were lower, which indicated that the ecological effect of grassland management measures was more positive in the developed regions. Although strict grassland-livestock balance policies had effectively altered the degradation trends in Inner Mongolia grassland, the economic growth still strongly relies on increasing livestock quantity within the grazing limitation, while those developed regions increased the economic benefits and also reduce the ecological pressure caused by livestock grazing in the meantime. Artificial pastures construction together with improved production efficiency effectively mitigated the ecological pressure on grasslands and also brought more economic benefits in those developed regions, which could also enlighten other developing regions to promoting sustainable utilization of grasslands and development of animal husbandry.

Responses of Land-Use Changes to Drought and its Disparate Impact on Livelihoods of Farmers and Herders in the Agro-Pastoral Ecotone of Northwestern China

The agro-pastoral ecotone is an ecologically fragile region where drought is the main factor influencing land use and livelihoods. In this paper, we took two farmer villages and two herder villages in Ar Horqin Banner, located in the agro-pastoral ecotone of northwestern China, as the research areas, and where we conducted participatory rural appraisal and questionnaire survey to analyze the responses of land-use changes to drought and its disparate impact on the livelihoods of farmers and herders. Results show that: 1) Under drought, farmers tended to abandon rain-fed land, and herders tended to abandon grassland. 2) The livelihood activities of farmers were more stable than those of herders under drought. Farmers abandoned rain-fed farming, and herders just retained cattle rearing. The per capita net income of each farmer in Pingandi and Fenghuangling in the drought year of 2016 was only 9.27% and 12.52% lower than those in 2012, respectively, which was 132.88% and 128.25% lower than those in 2012 of each herder in Wuriduhubu and Haolibao. 3) Diversified livelihoods, especially non-agricultural ones, are the key to ensuring the sustainable livelihoods of farmers and herders. It is an effective way for farmers to encourage more labor force to emigrate to non-agricultural sectors. Regarding herders, it is urgent to develop artificial pastures and animal products processing industry with the support of government.

Soil Characteristics and Arbuscular Mycorrhizal Fungi from Different Pasture Types: A Case Study in the Western Black Sea Region, Turkey.

This research was conducted to compare the soil characteristics and arbuscular mycorrhizal fungi (AMF) spore density from different types of pastures. To this purpose, four different areas were selected including an artificial pasture (AP), a fertilized artificial pasture (FAP), a natural pasture (NP), and a fertilized natural pasture (FNP). From the spring period of 2008, urea has been used as a fertilizer at an annual rate of 5kg/da. Different numbers of AMF spores were found in all soil samples taken from the artificial and natural pastures. The average numbers of AMF spores in 50g of soil from the AP, the FAP, the NP, and the FNP were determined as 266.9, 125.3, 117.0, and 59.6, respectively. Both the number of AMF spores and the number of species were found to be lower in the fertilized pastures, and consequently, it was concluded that the urea fertilizer had reduced the number of AMF spores and species. Spores were identified according to their morphological characteristics. In all pastures, the study identified 25 different AMF species belonging to 11 genera from 7 families. Rhizoglomus aggregatum was classified as the dominant species in FNP soils. Acaulospora dilatata, A. laevis, Dentiscutata heterogama, Diversispora eburnea, Gigaspora albida, G. margarita, Claroideoglomus etunicatum, C. lamellosum, Funneliformis caledonium, Glomus hoi, Rhizoglomus clarum, R. irregulare, Sclerocystis sinuosa, and Ambispora gerdemannii were classified as rare species in all pastures. This study demonstrated a negative correlation between the AMF spore density and the soil organic carbon, total nitrogen, and available potassium.

Application of Organic Fertilizer Changes the Rhizosphere Microbial Communities of a Gramineous Grass on Qinghai-Tibet Plateau.

The effects of organic fertilizer application on the soil microbial community in grassland systems have been extensively studied. However, the effects of organic fertilizers on the structure of rhizosphere microbial communities are still limited. In this study, the diversity and composition of rhizosphere microbial communities of a gramineous grass Elymus nutans under organic fertilizer treatment were studied in an artificial pasture on Qinghai–Tibet Plateau. After a growing season, the application of organic fertilizer not only increased the height and biomass of Elymus nutans, but also changed the rhizosphere microbial compositions. In particular, organic fertilizer increased the diversity of rhizosphere bacterial community and inhibited the growth of pathogenic bacteria such as Acinetobacter, but the opposite trend was observed for the diversity of fungal community. The assembly process of fungal community was changed from a stochastic process to a deterministic process, indicating that selection was strengthened. Additionally, both the infection rate of arbuscular mycorrhizal fungi (AMF) toward host plants and the development of AMF-related structures were significantly increased after the application of organic fertilizer. Our study demonstrated that the addition of organic fertilizer to artificial pasture could improve the growth of grass through the alteration of the rhizosphere microbial communities. Organic fertilizer had a greater selectivity for the bacterial and the fungal communities that enhanced the niche filtration in this community, further benefiting the yield of forages.

Compositional and structural changes in soil microbial communities in response to straw mulching and plant revegetation in an abandoned artificial pasture in Northeast China

The overgrazing and overutilization of pastures can lead to serious degradation that can be restored through proper management practices. However, little is known about the dynamic changes in soil microbial communities during such restoration processes. Therefore, we investigated the characteristics of changes in soil microbial communities during straw mulching and plant revegetation processes in an abandoned artificial pasture in Northeast China. We used 16S rRNA gene and ITS sequencing to analyze the composition and diversity of soil bacterial and fungal communities under control, straw mulching, Leymus chinensis revegetation, and straw mulching + L. chinensis revegetation treatments. Straw mulching was effective in enhancing the contents of total N, alkali-hydrolyzable N, and available P in soils under plant revegetation. The alpha diversity indexes of both bacterial and fungal communities decreased under all treatments. Plant revegetation and straw mulching had an additive effect on the bacterial community composition; their combination increased the absolute abundances of copiotrophic phyla, including Proteobacteria , Actinobacteria , Gemmatimonadetes , Bacteroidetes , and Acidobacteria . However, the response of the fungal community to these treatments was minimal. Moreover, redundancy analysis showed that the soil total N was the most important soil factor affecting the bacterial and fungal community compositions. Our findings highlight the additive effects of straw mulching and revegetation on soil microhabitats and soil bacterial communities, which enhanced the soil quality in an abandoned artificial pasture in Northeast China. • The change characteristics of soil microbial community during the restoration of an abandoned artificial pasture in Northeast China were studied. • The combination of straw mulching and plant revegetation had an additive effect on the soil microbial community composition and diversity as well as on soil properties. • The bacterial community responded more sensitively than the fungal community to restoration, and the bacterial communities changed from oligotrophic to copiotrophic communities. • Soil total nitrogen mainly contributed to explain the bacterial and fungal community compositions.

Warming reduces the production of a major annual forage crop on the Tibetan Plateau

Climate warming has been proposed to increase primary production of natural grasslands in cold regions. However, how climate warming affects the production of artificial pastures in cold regions remains unknown. To address this question, we used open-top chambers to simulate warming in a major artificial pasture (forage oat) on the cold Tibetan Plateau for three consecutive years. Surprisingly, climate warming decreased aboveground and belowground biomass production by 23.1%–44.8% and 35.0%–46.5%, respectively, without a significant impact on their ratio. The adverse effects on biomass production could be attributed to the adverse effects of high-temperatures on leaf photosynthesis through increases in water vapor pressure deficit (by 0.05–0.10 kPa), damages to the leaf oxidant system, as indicated by a 46.6% increase in leaf malondialdehyde content, as well as reductions in growth duration (by 4.7–6.7 days). The adverse effects were also related to exacerbated phosphorus limitation, as indicated by decreases in soil available phosphorus and plant phosphorus concentrations by 31.9%–40.7% and 14.3%–49.4%, respectively, and increases in the plant nitrogen: phosphorus ratio by 19.2%–108.3%. The decrease in soil available phosphorus concentration could be attributed to reductions in soil phosphatase activities (by 9.6%–18.5%). The findings of this study suggest an urgent need to advance agronomic techniques and cultivate more resilient forage genotypes to meet the increasing demand of forage for feeding livestock and to reduce grazing damage to natural grasslands on the warming-sensitive Tibetan Plateau.

Comparison of AET partitioning and water balance between degraded meadow and artificial pasture in Three‐River Source Region on the Qinghai‐Tibetan Plateau

AbstractActual evapotranspiration (AET) is the main component of water balance and comprises evaporation (E) and transpiration (T). Despite widespread recognition of the importance of water in terrestrial ecosystems, knowledge about key processes in the water balance is surprisingly limited, especially for how water is partitioned between E and T. We used a daily time step soil water model (SOILWAT2) and 10 years of data to describe AET partitioning and water balance of a degraded meadow and an artificial pasture in the Three‐River Source Region on the Qinghai‐Tibetan Plateau. Our results showed that there are two important environmental factors influencing water balance processes: evaporative demand of the atmosphere and precipitation. Due to the same evaporative demand and precipitation regime, the AET between our two sites was similar in seasonal trends and annual amounts. On an annual basis, AET and deep drainage accounted for almost 100% of the precipitation received by both the two sites. Despite the similarity of annual AET between the degraded meadow and the artificial pasture, the AET partitioning between the two sites was substantially different. Mean annual transpiration/actual evapotranspiration (T/AET) was 27% in the degraded meadow and 52% in the artificial pasture. The key controls on AET partitioning were vegetation and soil, and compared to soil, our study emphasized the influence of vegetation, and high amounts of biomass resulted in the highest values of T/AET in the artificial pasture. Additionally, we identified deep drainage as an important and previously overlooked component of water balance accounting for an average of approximately 21% of the annual precipitation in both the two study sites.