Grass Mixtures Research Articles

Evaluation of meadow fescue grass cultivars seeded with alfalfa in New York state

AbstractAlfalfa–grass mixtures sown in the northeastern United States provide high‐quality dairy forage, and meadow fescue (Festuca pratensis Huds.) may improve the quality of these mixtures. Our objectives were to evaluate competitiveness and nutritive value of nine meadow fescue (MF) cultivars in New York State at spring harvest. Three farms, two in central New York State and one in northern New York state, were used. Conventional alfalfa (Medicago sativa L.) was sown (15 lb acre−1) to nine MF cultivars (three tetraploid and six diploid) and one tall fescue Lolium arundinaceum (Schreb.) ‘Darbysh’ cultivar in a randomized complete block design with four field replicates at each field site at three seeding rates (1, 2, and 3 lb acre−1). Grass proportion in mixtures was estimated visually. Grass samples were collected shortly before first harvest and analyzed for neutral detergent fiber, neutral detergent fiber digestibility (NDFD), acid detergent fiber, in vitro digestibility, and crude protein. Most meadow fescue cultivars maintained a grass proportion between 20%–45% across farms and growing seasons when seeded at 1lb acre−1. Seeding rates above 1lb acre−1 resulted in grass proportions above the recommended 20–30% grass proportion rate. Drought in early 2022 resulted in an average drop in grass percentage of 16.9% units for meadow fescue in mixtures, compared to 2021. Nutritive value of cultivars varied among farms and over growing seasons. Meadow fescue cultivars averaged 2.7% units higher NDFD than tall fescue, and cultivars with consistently high NDFD were Hidden Valley, SW Revansch, SW Minto, and Schwetra. Tetraploid cultivars averaged 4.0% units lower NDF compared to diploid cultivars, which is very advantageous for grass in alfalfa–grass mixtures.

ACCUMULATION OF SYMBIOTIC NITROGEN BY PERENNIAL LEGUMINOUS CROPS IN THE SOUTHERN STEPPE OF UKRAINE

The use of perennial leguminous crops is an energetically and economically beneficial and ecologically safe measure for improving the nitrogen balance of soils, which implementation requires specification and additional research of certain soil and climatic conditions and farming systems. The work aimed at studying the accumulation of biologically bound nitrogen by alfalfa and Hungarian sainfoin in single-species crops, as well as in wheatgrass-alfalfa and wheatgrass-sainfoin grass mixtures on the dark-chestnut soil of southern Ukraine. Laboratory, field, and statistical research methods were applied. The obtained results showed that the accumulation of nitrogen in the biomass of leguminous perennial grasses in single-species crops of blue hybrid alfalfa, Hungarian sainfoin, and intermediate wheatgrass and their grass mixtures depended on the hydrothermal conditions of the growing season, changes in species botanical composition by the years of grass stand used. During the first and second years of use, the nitrogen content in the biomass of alfalfa was 3,54-3,75%, sainfoin – 3,49-3,65%, and was significantly higher than in single-species crops of intermediate wheatgrass – 2,62-2,77% to dry matter. The removal of total nitrogen by intermediate wheatgrass during this period did not exceed 90 kg/ha; by alfalfa and sainfoin, it was 125-134 kg/ha, including symbiotic nitrogen removed by the alfalfa crop – 35-39 kg/ha and Hungarian sainfoin – 37-44 kg /ha. In the fractional composition of nitrogen in the soil of the experimental field after three years of using alfalfa when inoculating seeds with the complex microbial preparation Ecovital, the nitrogen content was the highest compared to other types of crop rotation, including total nitrogen – 1006,3-1428,8, mineral nitrogen – 24,9-46,3; alkaline hydrolyzed nitrogen – 113,8-186,0 mg/kg of soil. The obtained results allow us to conclude that the creation of highly productive symbiotic systems when using the latest biological preparations will contribute to improving soil nitrogen balance, eliminate the catastrophic decrease in fertility and soil degradation, improve the fodder base for animal production, and reduce the ecological burden on agricultural lands.

Параметри на зависимостта „добив – евапотранспирация по подрасти“ при тревна смеска от английски райграс (Lolium perenne L.) и червена власатка (Festuca rubra L.)

The aim of the study is to establish the parameters of the relationship „Yield-ET by swaths” in a grass mixture of English ryegrass (Lolium perenne L.) and Red fescue (Festuca rubra L.). Data from an experiment with the application of a regulated water deficit, conducted at the Forestry University - Sofia, were used. The output data included the relative values of yield and evapotranspiration (ET) for each of the sub-crops separately. Two types of formulas were used: for the relationship „Yield-seasonal ET” and for the relationship „Yield-ET by phenophases”. From the first group, the two-power equation is recommended, according to which the first three swaths have greater requirements for ET, which can form some yield when providing at least 40-50% of the maximum ET. The fourth and fifth swaths show smaller requirements, but the differences compared to the first three swaths are in the range of 10-30%. Of the second group of equations, Steward’s linear formula, modified for use in swath crops, is recommended. It presents the relationship most realistically with R=0.983 and minimal difference between different swaths in terms of their sensitivity.

Green Roof Substrate Microbes Compose a Core Community of Stress-Tolerant Taxa.

Extensive green roofs provide for many ecosystem services in urban environments. The efficacy of these services is influenced by the vegetation structure. Despite their key role in plant performance and productivity, but also their contribution to nitrogen fixation or carbon sequestration, green roof microbial communities have received little attention so far. No study included a spatiotemporal aspect to investigate the core microbiota residing in the substrates of extensive green roofs, although these key taxa are hypothesized to be amongst the most ecologically important taxa. Here, we identified the core microbiota residing in extensive green roof substrates and investigated whether microbial community composition is affected by the vegetation that is planted on extensive green roofs. Eleven green roofs from three different cities in Flanders (Belgium), planted either with a mixture of grasses, wildflowers and succulents (Sedum spp.; Sedum-herbs-grasses roofs) or solely species of Sedum (Sedum-moss roofs), were seasonally sampled to investigate prokaryotic and fungal communities via metabarcoding. Identifying the key microbial taxa revealed that most taxa are dominant phylotypes in soils worldwide. Many bacterial core taxa are capable of nitrogen fixation, and most fungal key taxa are stress-tolerant saprotrophs, endophytes, or both. Considering that soil microbes adapted to the local edaphic conditions have been found to improve plant fitness, further investigation of the core microbiome is warranted to determine the extent to which these stress-tolerant microbes are beneficial for the vegetational layer. Although Sedum-herbs-grasses roofs contained more plant species than Sedum-moss roofs, we observed no discriminant microbial communities between both roof types, likely due to sharing the same substrate textures and the vegetational layers that became more similar throughout time. Future studies are recommended to comprehensively characterize the vegetational layer and composition to examine the primary drivers of microbial community assembly processes.

A short-term effect of multi-species pastures and the plant’s physiological response on pasture growth

Multi-species pastures that include species with dissimilar physiological responses to water restriction (i.e., dehydration avoidance) and species that have a greater soil water access (i.e., deep-rooted species), can buffer the reduction in summer growth experienced by more shallow-rooted species and can out-yield pastures with less capacity to access soil water. The aim of the present study was to evaluate the performance of multi-species pastures comprising both deep-rooted and shallow-rooted species, under grazing by sheep, in relation to pasture growth, the seasonal changes in pasture botanical composition, and the plants’ physiological responses to field conditions across the year. The evaluated pastures were: Bromus valdivianus (Bv); Lolium perenne + Trifolium repens (Lp); Plantago lanceolata (Pl); B. valdivianus + L. perenne + T. repens (grass mixture pasture, GM); and B. valdivianus + L. perenne + T. repens + P. lanceolata (complex mixture pasture, CM). Herbage mass, net photosynthesis, leaf water relations and soil water content (SWC) at 10, 40 and 70 cm soil depths were evaluated. The SWC fluctuation through the year was related to rainfall within each season, and differences between the treatments were taken as an indirect indicator of soil water access and soil water uptake by the roots. During the soil water restriction period, mixed pastures based on species that differed in their soil water access buffered the reduced growth rate of the sensitive species, due to a decrease in competition for water uptake within the deeper soil layer (CM pasture). A shift of dominance between species, as measured in the CM pasture, buffered the reduction in pasture growth rate seen in the monocultures. The Bv pasture, which is tolerant of water restriction, had a similar annual yield to the multi-species pastures (both GM and CM). The present study highlighted the capacity of the deep-rooted species (B. valdivianus and P. lanceolata) to avoid periods of soil water restriction by extracting water from deeper soil layers.

Legume–grass mixtures improve biological nitrogen fixation and nitrogen transfer by promoting nodulation and altering root conformation in different ecological regions of the Qinghai–Tibet Plateau

Legume–grass mixtures improve biological nitrogen fixation and nitrogen transfer by promoting nodulation and altering root conformation in different ecological regions of the Qinghai–Tibet Plateau

Effects of kinds of additives on fermentation quality, nutrient content, aerobic stability, and microbial community of the mixed silage of king grass and rice straw.

To investigate the effects of kinds of additives on silage quality, the mixture of king grass and rice straw was ensiled with addition of sucrose, citric acid and malic acid at the levels of 0, 1 and 2%, being blank control (CK), citric acid groups (CA1, CA2), malic acid groups (MA1, MA2), citric acid + malic acid groups (CM1, CM2), sucrose groups (SU1, SU2), mainly focusing on fermentation quality, nutrient content, aerobic stability and microbial community of the silages. The results showed that the addition of sucrose decreased (p < 0.05) pH and increased the content of water soluble carbohydrate (p < 0.05). The sucrose groups and mixed acid groups also had a lower (p < 0.01) neutral detergent fiber content. The addition of citric acid and the mixed acid increased (p < 0.01) the aerobic stability of the silage, reduced the abundance of Acinetobacter, and the addition of citric acid also increased the abundance of Lactiplantibacillus. It is inferred that citric acid and malic acid could influence fermentation quality by inhibiting harmful bacteria and improve aerobic stability, while sucrose influenced fermentation quality by by promoting the generation of lactic acid. It is suggested that the application of citric acid, malic acid and sucrose would achieve an improvement effect on fermentation quality of the mixed silage.

Effects of forages on the microbiota of crossed sheep on cold Plateau

Diet is an important component to influence microbiota, there are less data available about the microbiome of Suffolk cross with Tibetan (SCT) animals with different fodders. The current study was conducted for comparing the fungi microbiota in SCT sheep fed with different forages. Sequencing of ileum samples from sheep groups of AH (alfalfa and oat grass), BH (mixture of grass and concentrated feeds), CH (concentrated feed I), DH (concentrated feed II) and EH (concentrated feed III) achieved 3,171,271 raw and 2,719,649 filtered sequences. Concentrated feeds changed fungi microbiota in SCT sheep with three phyla and 47 genera significantly different among the groups. Genera include positive genus of Scytalidium and negative fungi of Sarocladium, Kazachstania, Gibberella, Scytalidium, Candida, Wickerhamomyces. The findings of our study will contribute to efficient feeding of SCT sheep at cold plateau areas.

Design Analysis and Production of Biogas Using Local Feedstock “Elephant Grass”

The study was aimed at constructing a biodigester and determining the efficiency of using a mixture of cow dung and elephant grass as feedstock for biogas production. The volume of the biodigester was 126 litres (0.126m3) and it was constructed using mild steel with a thickness of 5mm and a maximum allowable stress of 1.74 N/mm2 to withstand high pressures that could be generated within the digester. 6 kg of elephant grass was mixed with 6 kg of cow dung and 12 litres of water and poured in the biodigester and left for a period of 21 days with a temperature range of 35°C - 44°C. Graphs of temperature (°C) against retention period (days) and daily biogas produced (litres) against retention period (days) were obtained. The daily biogas yield was measured by calculating the volume increase of the storage device which is a car tyre tube in this case. Elephant grass serves as an effective substrate for biogas production. To enhance its efficiency in the digester, it is recommended to mechanically pre-treat the grass by breaking it into smaller particles.

A comparative analysis of perennial grass–legume mixtures for biomethane production

Examining the case of Lithuania, this study comparatively analyzed five perennial grass–legume mixtures in terms of biomethane production. Every mixture was divided into two parts: long (during the fifth year or beyond) and short (during the first four years) time periods. The analysis includes three types of perennial bell grass: Timothy, P. Ryegrass, C. Cocksfoot, and one legume grass Red clover. With this study, we aimed to evaluate how perennial grass–legume mixtures can promote biomethane uptake in Lithuania. Through analyzing the efficiency and consequences of government subsidy measures, this study aimed to address the question of how governmental assistance can promote the growth of the biomethane industry, specifically focusing on the utilization of perennial grass–legume mixtures. This study used seven financial indicators, including subsiding policy, in order to gain a deeper understanding of mixtures for biomethane production. The analysis revealed that the best mixtures for biomethane production with subsidies were the second (Red clover 35 % + Timothy 45 % + Ryegrass 20 % grass mixture) and fourth scenarios (Red clover 55 % + Ryegrass 45 % grass mixture). The first (Red clover 35 %. + Timothy 25 % + Ryegrass 20 % + Cocksfoot 20 % grass mixture), third (Red clover 55 % + Timothy 45 % grass mixture), and fifth scenarios (Red clover 55 % + Cocksfoot 45 % grass mixture) had the smallest positive effects. The results showed that, in Lithuania, in order to encourage farmers to produce biomethane, subsidy policies are needed. Incentives for engaging with this activity are necessary, as the income earned does not cover the costs incurred; unfortunately, biomethane production is unprofitable without subsidy. As such, our recommendation is to develop a long-term subsidy policy to promote biomethane production, focusing on the effectiveness, particularly in the Lithuanian context, of utilizing mixtures of perennial grasses. Further research and policy interventions are needed to address the opportunities associated with scaling synergy between perennial energy cops and environmental sustainability in bioenergy crop cultivation.

Reducing industrial inputs – a prerequisite for the transition to sustainable agriculture

This article provides the results of a long-term field experiment carried out at the ICC "Selectia" with the aim of studying the influence of irrigation and fertilisation on the production capacity and productivity of the soil and, at the same time, on soil fertility. Another long-term field experiment aimed to study the action and interaction of crop rotation, tillage, and fertilisation systems in the absence of chemical means of disease, pest and weed control. As a result, it was found that winter wheat responds to irrigation, unlike sugar beet, which responds more to soil fertilisation. Grain maize does not react to crop rotation and fertilisation. Irrigation reduces organic matter content throughout the soil profile. By following the crop rotation with the inclusion of perennial grass mixtures it is possible to reduce the costs of tillage and the use of mineral fertilisers. The additional use of mineral fertilisers as a result of the action or the effect of manure management in the soil is not agronomically and economically justified.

Bacteria, Fungi, and Protists Exhibit Distinct Responses to Managed Vegetation Restoration in the Karst Region.

Bacteria, fungi, and protists occupy a pivotal position in maintaining soil ecology. Despite limited knowledge on their responses to managed vegetation restoration strategies in karst regions, we aimed to study the essential microbial communities involved in the process of vegetation restoration. We compared microbial characteristics in four land use types: planted forests (PF), forage grass (FG), a mixture of plantation forest and forage grass (FF), and cropland (CR) as a reference. Our findings revealed that the richness of bacteria and protists was higher in FF compared to PF, while fungal richness was lower in both PF and FF than in CR. Additionally, the bacterial Shannon index in FF was higher than that in CR and PF, while the fungal and protist Shannon indices were similar across all four land use types. Significant differences were observed in the compositions of bacterial, fungal, and protist communities between FF and the other three land use types, whereas bacterial, fungal, and protist communities were relatively similar in PF and FG. In FF, the relative abundance of bacterial taxa Acidobacteria, Firmicutes, and Gemmatimonadetes was significantly higher than in PF and CR. Fungal communities were dominated by Ascomycota and Basidiomycota, with the relative abundance of Ascomycota significantly higher in FF compared to other land use types. Regarding protistan taxa, the relative abundance of Chlorophyta was higher in FF compared to CR, PF, and FG, while the relative abundance of Apicomplexa was higher in CR compared to FF. Importantly, ammonium nitrogen, total phosphorus, and microbial biomass nitrogen were identified as key soil properties predicting changes in the diversity of bacteria, fungi, and protists. Our results suggest that the microbial community under FF exhibits greater sensitivity to vegetation restoration compared to PF and FG. This sensitivity may stem from differences in soil properties, the formation of biological crusts and root systems, and management activities, resulting in variations in bacterial, fungal, and protist diversity and taxa in PF. As a result, employing a combination restoration strategy involving plantation forest and forage grass proves to be an effective approach to enhance the microbial community and thereby improve ecosystem functionality in ecologically fragile areas.

Systems management strategies for increasing alfalfa use in warm‐humid regions

AbstractAlfalfa use (Medicago sativa L.; “lucerne”) in warm, humid regions of the world represents a potential area of expansion for the alfalfa industry. The objective of this review paper is to demonstrate how alfalfa forage breeding and systems research efforts have identified opportunities for increasing alfalfa contributions in these regions, along with potential pathways for seed industry and farming operations to increase adoption. Our review draws primarily on reports from the Southeast United States and Argentina. Significant technological advancements in plant screening and selection have identified alfalfa plant populations that are more adapted to the growing conditions experienced in these regions, which are often characterized by mild temperature, long growing seasons, and multiple other abiotic and biotic stressors. Management systems research conducted in the United States and Argentina has demonstrated the use of alfalfa for conserved forage, grazing, or dual‐purpose use in monoculture or mixtures with warm‐season grasses such as bermudagrass (Cynodon spp.). These trials report increased forage production, nutritive value, and ecosystem services of alfalfa–grass mixtures when compared with traditionally N‐fertilized warm‐season grass‐based systems. Grazing‐based alfalfa systems in Argentina have demonstrated methods for utilizing alfalfa as part of beef, dairy, and finishing systems. Some approaches for expanding alfalfa production in the region include targeted marketing efforts for adapted varieties and demonstrating alfalfa applications within existing farming frameworks. This includes educational programming efforts and on‐farm demonstrations to promote alfalfa use as a component of the livestock diets, integration into grass‐based systems, crop rotations, and wildlife use. Continued emphasis on a systems approach to alfalfa inclusion represents an opportunity for improved forage and livestock production in warm, humid regions of the world.

Evaluation of strategies to improve the quality of Tanzania grass (Megathyrsus maximum) silage with increasing levels of mata-pasto hay (Senna obtusifolia)

Context Seasonal variations between the rain and dry seasons are the main obstacle to agricultural productivity in tropical regions, making it essential to conserve surplus for periods of scarcity. One of the limiting factors in ensiling grasses is moisture, requiring the use of additives or withering. Using a mixture of grasses and legumes can be an alternative to balance the advantages and disadvantages of both in the ensiling process, and mata-pasto hay (MPH) can be an option. Aims This study evaluated different forms of Tanzania grass (Megathyrsus maximum) and MPH silages, as well as silages with increasing levels of MPH. Methods Silages of Tanzania grass and MPH in their natural form, as well as silages with increasing doses of MPH, were evaluated for nutritional value, degradability in situ. The microbiology was also evaluated. Key results Among the types of silages, natural MPH and wilted MPH were superior to natural Tanzania grass silage. The use of MPH in Tanzania grass silages improves fermentation processes, the population of beneficial microorganisms, resulting in better nutritional value of these silages. Conclusions Natural and wilted MPH hay silages are qualitatively better compared to natural Tanzania grass silage. Increasing doses of MPH improve the quality of the silage. A recommended dose is 30% of MPH hay. Implications Adding MPH to silages is a way to reduce the negative impacts of this weed on pastures. However, further studies with the use of complementary additives are needed.

Changing pasture management practices on the Greek island of Samothraki: Obstacles and opportunities

ContextOn the Greek island of Samothraki, decades of overgrazing by the large domestic population of small ruminants accelerated soil degradation and surface erosion, with direct consequences for ecosystem functioning and the delivery of ecosystem services. ObjectiveThis manuscript reports on a 5-year research project to achieve more sustainable pasture management practices among small ruminant farmers on the island, through the introduction of Sown Biodiverse Pastures (SBP). This practice, based on sowing a seed mixture of legumes and grasses that increase pasture productivity, has proven to be a successful tool to overcome degradation of ruminant pastures in Portugal. MethodsLocal small ruminant farmers on Samothraki, a difficult group when it comes to the acceptance of new practices and ideas, were engaged in the transdisciplinary research process, and trained in appropriate management practices of SBP. This led to the adoption and implementation of SBP by nine farmers on 13 parcels. Results and conclusionsQuantitative data on species composition and productivity shows that the performance and persistence of SBP on Samothraki is favourable, if soil preparation and sowing is practiced as recommended, and relevant management practices are adopted. Comparing with conventional agricultural practices, i.e. annual crop – fallow rotation, productivity in SBP outperformed the forage quantity in fallow land, while yield in the annual crop was approximately equal as compared to SBP. The increasing forage capacity of SBP instigates several environmental and economic benefits, such as a reduction of grazing pressure in vulnerable areas, and less expenditure on supplementary feed requirements. However, lack of will and trust in these new practices and seed mixtures among local farmers resulted in discontinuation in almost half of the parcels. The adoption of new management practices by the farming community on Samothraki required continuous efforts, and the short-term framework of the research project did not favour long-term success. SignificanceIt is recommended for any programs aiming at changing farming practices to engage with local stakeholders, especially farmers, and to closely collaborate with local institutional partners who can carry the work forward after scientific researchers have left.

Predicting grass proportion in fresh alfalfa: Grass mixtures using a hand‐held near‐infrared spectrometer

AbstractTechnological advancements have made hand‐held near infrared (NIR) spectrometers more affordable and more accurate, creating interest in on‐farm application for forage management. The objective of this study was to evaluate the ability of a hand‐held NIR spectrometer to predict grass percentage within fresh alfalfa (Medicago sativa L.):grass mixtures. Forage samples were collected at a range of maturities and varieties during the 2021 and 2022 growing seasons from multiple locations in New York. Fresh forage samples were chopped, and pure species were combined into known proportions on a dry matter basis, resulting in 534 samples. Analysis was carried out on NIR spectra collected from a hand‐held NeoSpectra spectrometer using stationary and sliding scanning techniques. Development of calibration models was completed using partial least squares regression with cross validation. The best performing calibration model using absorbance was from the sliding scanning technique with preprocessing consisting of mean‐centering (R2 = 0.89, root mean square error of prediction [RMSEP] = 13.7%, and ratio of prediction to deviation = 2.53). A total of 84% of the samples were correctly classified when the grass component was lower than 40%. For samples with the grass component above 40%, a total of 94% of the samples were correctly classified. Correct sample classification is critical considering that the extension recommendation in New York is to reseed alfalfa fields when the grass component exceeds 40% of the sward on a botanical composition basis. This research demonstrates that NIR technology has potential to provide the agricultural industry with rapid, non‐destructive, and affordable information to allow farmers and consultants to predict grass proportion within alfalfa:grass fresh forage mixtures in real time.

Effectiveness of sod and humus soil maintenance and biologized protection in intensive apple orchards (Malus domestica Borkh.) in the south of Russia

Application of intensive technologies in horticulture with a high mechanical and chemical load on soils and fruit plants leads to deterioration of soil properties, environmental pollution, and development of resistance among pathogens and phytophages. In this study, we aim to developing a biologized technology for apple tree cultivation using a sod and humus system of inter-row maintenance and biopreparations based on active strains of microorganisms, entomoacariphages, and pheromones. The research was conducted in 2019-2023 in intensive apple orchards of the central plain-steppe region of Crimea by the methods conventionally used in soil science, agrochemistry, horticulture, and plant protection. The use of a mixture of cereal-legume grasses in combination with microbiological fertilizers based on nitrogen-fixing microorganisms was found to increase apple yields by 11–12 t/ha, or 64 % compared to the control, by increasing the number of fruits and the average weight of one fruit. A positive balance of nutrition elements in soil with an intensity of 135-270 % was established. The efficiency of controlling the number of phytophages and pathogen harmfulness through the integrated use of biological and biotechnical methods was shown. Thus, the “attract-and-kill” method for Cydia pomonella L. pheromones demonstrated a 98 % efficiency along with a reduction in pesticide load to 7.7 kg/ha season by the preparation. Release of phitoseiid mites for control of tetranychus mites by the method of seasonal colonization provides for a reduction and retention of phytophagous population at the economic threshold of harmfulness during the entire vegetation period. The use of fungicides based on pathogenic bacteria of the Bacillus genus and antagonist fungi of the Trichoderma genus against scab is eff ective only in the years unfavorable for the development of the disease. The results obtained form the basis for a biologized resource-saving technology for exploitation of intensive apple orchards. This technology contributes to increased soil fertility, reduced chemical and pesticide load, and increased productivity of horticultural agrocenosis under the conditions of the Crimea and southern Russia.

Impacts of Managed Vegetation Restoration on Arbuscular Mycorrhizal Fungi and Diazotrophs in Karst Ecosystems.

The crucial functional arbuscular mycorrhizal fungi (AMF) and diazotrophs play pivotal roles in nutrient cycling during vegetation restoration. However, the impact of managed vegetation restoration strategies on AMF and diazotroph communities remains unclear. In this study, we investigated the community structure and diversity of AMF and diazotrophs in a karst region undergoing managed vegetation restoration from cropland. Soil samples were collected from soils under three vegetation restoration strategies, plantation forest (PF), forage grass (FG), and a mixture of plantation forest and forage grass (FF), along with a control for cropland rotation (CR). The diversity of both AMF and diazotrophs was impacted by managed vegetation restoration. Specifically, the AMF Shannon index was higher in CR and PF compared to FF. Conversely, diazotroph richness was lower in CR, PF, and FG than in FF. Furthermore, both AMF and diazotroph community compositions differed between CR and FF. The relative abundance of AMF taxa, such as Glomus, was lower in FF compared to the other three land-use types, while Racocetra showed the opposite trend. Among diazotroph taxa, the relative abundance of Anabaena, Nostoc, and Rhizobium was higher in FF than in CR. Soil properties such as total potassium, available potassium, pH, and total nitrogen were identified as the main factors influencing AMF and diazotroph diversity. These findings suggest that AMF and diazotroph communities were more sensitive to FF rather than PF and FG after managed vegetation restoration from cropland, despite similar levels of soil nutrients among PF, FG, and FF. Consequently, the integration of diverse economic tree species and forage grasses in mixed plantations notably altered the diversity and species composition of AMF and diazotrophs, primarily through the promotion of biocrust formation and root establishment.

Состояние почвенного покрова и фитомелиорация пастбищ в районах Восточного Предкавказья

Introduction. The arid zone of the Eastern Ciscaucasia, and specifically the extremely arid and arid areas of the Stavropol Territory, with low-fertile pasture soil cover, are subject to degradation associated with both soil and climatic conditions and anthropogenic technological load on the soil. Materials and methods. The manifestation and areas occupied by soil degradation factors (the presence of salt marshes, salt marshes, erosion and deflation) in each of the districts are different, therefore, for a comprehensive assessment of the level of degradation in a particular area, calculations of the generalized indicator of degradation of the soil cover of pastures are carried out. Results and discussion. Based on a systematic analysis, with an assessment of the desirability and weight of each of the degradation factors, it was found that the soil cover of the pastures of the Kursk region is subject to a moderate level of degradation (Dp=0.95), Ipatovsky district with Dp=0.90 – increased, and Apanasenkovsky Turkmen, Arzgir, Levokumsky, Neftekumsky districts – a high level of degradation with Dp=0.822–0.828. Сonclusion. In an area with a moderate level of degradation of the pasture soil cover, a superficial improvement of the natural herbage is proposed with the addition of perennial grasses to it: Medicagovaria, Melilotusofficinalis, Melilotus album, Agropyron fragile, Kochiaarenaria. With an increased and high level of degradation of pasture soils, it is advisable to radically improve with the use of legume-cereal grass mixtures from Medicagofalcata, Medicagovaria, Onobrychisarenaria, Agropyron fragile, Elytrigiaintermedia, Bromopsisinermis, Kochiaarenaria. On saline soils, it is also effective to use both Medicago falcate and Medicagovaria and Agropyrondesertorum, Agropyroncristatum, Elytrigiaintermedia, Bromopsisinermis, Kochiaarenaria, Bassiaprostrata, Melilotusofficinalis, Melilotus album, Festucavalesiaca, Leymusracemosus. Suggestions for practical application and direction of future research. The developed map-scheme of degradation of the soil cover of pastures of the Stavropol Territory districts, indicating the numerical values of the complex indicator Dp, allows you to make certain technological decisions on carrying out a complex of phyto-meliorative measures on pastures specifically for each district of the Eastern Caucasus.

Влияние различных фитомелиорантов на плодородие и оптические показатели агрогенных почв Приморья

The influence of various phytomeliorants on the content and reserves of humus, the content of microelements, microflora and optical parameters of agrogenic soils of Primorye were studied. Sowing legumes with annual and perennial crops activates the processes of humus accumulation, increases the biogenicity and catalase activity of soils. The most positive effect on the increase in humus content, catalase activity and soil biogenicity in the experiment with annual grasses was noted for the “oats + vetch” guide. Humus reserves reached the level of average values. In the variant of the experiment, “oats + beans”, the amount of humus and its reserves in the 20 cm layer decreased due to waterlogging of the soil and the weakening of the processes of transformation of organic matter by microflora. In the experiment with perennial grasses, the highest humus content and indicators of catalase activity were recorded for the “timothy grass + alfalfa” variant, the “timothy grass + clover + alfalfa” variant differed in the largest reserves of humus and biogenicity. Due to the decrease in the density of soil composition, in the variant with the sowing of the grass mixture of timothy “grass + alfalfa”, the humus reserves in the 20 cm layer decreased slightly (to 108.6 t/ha). A close inverse correlation was established between the addition of humus and the integral reflection. When considering with regional clarke values, an imbalance in the microelement composition of the studied soil samples of the upper horizon was revealed.