Grass-legume Mixtures Research Articles

Effects of legumes and fertiliser on nitrogen balance and nitrate leaching from intact leys and after tilling for subsequent crop

Grass-legume leys combine multiple agronomic benefits, several of which are associated with symbiotic nitrogen (N) fixation. However, the best combinations of legume abundance and N fertilisation to achieve high productivity at low nitrate leaching are not yet established. Nitrate leaching risk of pure grass swards (Grs), grass-legume mixtures (Mix) and pure legume swards (Leg) at a fertiliser level of either 50, 150 or 450 kg N ha−1 yr−1 (N50, N150 and N450) was studied during two key periods: the intact ley for forage production and after tilling for subsequent winter wheat in crop rotation. The risk of nitrate leaching was determined from (i) monitoring of the nitrate concentration in the soil solution (NCSS) and (ii) the soil mineral N (SMN) content. Furthermore, the soil surface N balance was assessed by measuring N input from fertiliser and symbiosis, and N output with harvested biomass. During the period of intact plant cover, soil surface N balance of Grs swards was strongly negative at N50 and N150 with negligible NCSS and SMN. At N450, the positive N balance of Grs swards resulted in a high leaching risk after three years of cultivation (NCSS ≤ 13 mg NO3-N L−1 and SMN ≤ 20 kg N ha−1). For Mix swards, the N balance was close to zero at N50 and N150, which led to similarly low NCSS and SMN. At N450, the N balance of Mix swards was beyond zero, resulting in significantly increased NCSS and SMN (≤ 30 mg NO3-N L−1 and ≤ 35 kg N ha−1). For Leg swards, the N balance was far beyond zero at all fertilisation levels, resulting in a leaching risk even at N50 (≤ 8 mg NO3-N L−1 and ≤ 23 kg N ha−1). During the period following tilling the leys, SMN was similar or lower for Mix compared to Grs swards (≤ 43 vs. ≤ 62 kg N ha−1 at N50 and N150, 72 vs. 68 kg N ha−1 at N450), while it was significantly higher for Leg swards (SMN ≤ 95 kg N ha−1). We conclude that grass-legume mixtures combine high yields, low fertiliser requirements, and low nitrate leaching better than either pure grass or pure legume swards. This holds true both during the period with intact plant cover and after tillage for the subsequent crop.

Grass-legume mixtures maintain forage biomass under microbial diversity loss via gathering Pseudomonas in root zone soil.

Grass-legume mixtures are a common practice for establishing artificial grasslands, directly or indirectly contributing to the improvement of yield. In addition, this method helps maintain soil and plant health by reducing the use of chemical fertilizers. The impact of grass-legume mixtures on yield and its underlying microbial mechanisms have been a focus of scientific investigation. However, the benefits of mixtures in the context of soil microbial diversity loss remain a problem worthy of exploration. In this study, we examined different aboveground and belowground diversity combinations to elucidate the mechanisms by which grass-legume mixtures help maintain stable yields in the face of diversity loss. We identified the significantly enriched Pseudomonas genus microbial ASV53, which was gathered through homogeneous selection and served as a keystone in the co-occurrence network. ASV53 showed a strong positive correlation with biomass and the abundance of nitrogen-fixing genes. These findings provide a new theoretical foundation for utilizing grass-legume mixtures to enhance grass yields and address the challenges posed by diversity loss.

Legume-grass mixtures increase forage yield by improving soil quality in different ecological regions of the Qinghai-Tibet Plateau.

Information on the relationship between soil quality and forage yield of legume-grass mixtures in different ecological regions can guide decision-making to achieve eco-friendly and sustainable pasture production. This study's objective was to assess the effects of different cropping systems on soil physical properties, nitrogen fractions, enzyme activities, and forage yield and determine suitable legume-grass mixtures for different ecoregions. Oats (Avena sativa L.), forage peas (Pisum sativum L.), common vetch (Vicia sativa L.), and fava beans (Vicia faba L.) were grown in monocultures and mixtures (YS: oats and forage peas; YJ: oats and common vetch; YC: oats and fava beans) in three ecological regions (HZ: Huangshui Valley; GN: Sanjiangyuan District; MY: Qilian Mountains Basin) in a split-plot design. The results showed that the forage yield decreased with increasing altitude, with an order of GN (3203 m a.s.l.; YH 8.89 t·ha-1) < HZ (2661 m; YH 9.38 t·ha-1) < MY (2513m; YH 9.78 t·ha-1). Meanwhile, the forage yield was higher for mixed crops than for single crops in all ecological regions. In the 0-10 cm soil layer, the contents of total nitrogen (TN), microbial biomass nitrogen (MBN), soil organic matter (SOM), soluble organic nitrogen (SON), urease (UE), nitrate reductase (NR), sucrase (SC), and bacterial community alpha diversity, as well as relative abundance of dominant bacteria, were higher for mixed crops than for oats unicast. In addition, soil physical properties, nitrogen fractions, and enzyme activities varied in a wider range in the 0-10 cm soil layer than in the 10-20 cm layer, with larger values in the surface layer than in the subsurface layer. MBN, SON, UE, SC and catalase (CAT) were significantly and positively correlated with forage yield (P < 0.05). Ammonium nitrogen (ANN), nitrate nitrogen (NN), SOM and cropping systems (R) were significantly and positively correlated with Shannon and bacterial community (P < 0.05). The highest yields in the three ecological regions were 13.00 t·ha-1 for YS in MY, 10.59 t·ha-1 for YC in GN, and 10.63 t·ha-1 for YS in HZ. We recommend planting oats and forage peas in the Qilian Mountains Basin, oats and fava beans in the Sanjiangyuan District, and oats and forage peas in Huangshui valley. Our results provide new insights into eco-friendly, sustainable, and cost-effective forage production in the Qinghai Alpine Region in China.

The effects of functional trait diversity on productivity of grass-legume swards across multiple sites and two levels of nitrogen fertiliser

Productive and stable forage yields are essential for the sustainability of ruminal livestock production. Grassland seed mixtures composed of species of diverse functional groups have previously been demonstrated to increase yield performance and stability compared to monocultures. In this study we conducted field trials with five grass and two legume species either grown in monocultures or a range of mixtures from two-species to seven-species mixtures sown in a simplex design. The species represented different functional groups regarding ability to fixate atmospheric nitrogen (N), rate of establishment and temporal persistence.The experiments were established with the same cultivars of species at five locations in Norway with climatically contrasting environments – from mild humid, mountainous continental to sub-arctic. The experimental plots were harvested for three years at four of the sites and two years at one of the sites, and they were fertilised according to normal practise in intensive silage grass production in the respective regions (regular N). At three of the sites, a treatment with low mineral N supply rate was also included.We found that crops sown as mixtures returned higher yields and contained less weeds than the average of monoculture crops, and these effects were consistent over all sites and study years. The grass-legume mixtures managed at low N supply rate performed equally well or better than monocultures or grass-only mixtures managed at regular N supply. We found no effects of the functional groups categorised as temporal persistence or rate of establishment on the yield performance, and there were no apparent benefits of increasing the number of species beyond the species P. pratense, F. pratensis and T. pratense over the three production years the experiments lasted.The results suggest that by using grass-clover mixtures, farmers can reduce N fertiliser rates, without compromising productivity of temporary grassland under northern conditions over the first three years of production.

Effect of Biochar Application and Mineral Fertilization on Biomass Production and Structural Carbohydrate Content in Forage Plant Mixture

Biochar, a fine-grained porous material, exhibits properties that improve soil quality on agricultural land. Biochar, in combination with mineral fertilizers in perennial mixed crops, has so far not been studied for its effect on biomass production and feed value. The study, conducted in 2021 and 2022, aims to investigate the impact of different biochar application rates (alone and in combination with high and low NPK (nitrogen, phosphorus, potassium) fertilizer dosages) on the yield and structural carbohydrate content in grass–legume mixtures. Thus, a two-factorial pot study consisting of 36 pots was established in 2021. The study was set up in a randomized block design with nine fertilization treatments in four replicates. The factors studied were the rate of biochar (0, 5, and 10 Mg ha−1) and the rate of NPK mineral fertilizer application (0, 105, and 185 kg ha−1). First, biochar was applied and then the grass–legume mixture was sown, consisting of Lolium perenne L., Festuca arundinacea Schreb., Dectylis glomerata L., Lolium multiflorum Lam., Phleum pratense L., Festuca rubra L., Festuca ovina L., Poa pratensis L., Trifolium repens L., and Medicago sativa L. In both years of the study, during the growing season, plant biomass was harvested three times to assess biomass production and structural carbohydrate content. In the collected samples, neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) were examined, and, based on these, dry matter digestibility (DDM), dry matter intake (DMI), and relative feed value (RFV) were calculated. Compared to the control, the biochar addition increased the biomass production by 6.7–14.4% in the first year and by 49–59% in the second year after application. The addition of biochar in combination with NPK fertilization caused an increase in biomass production—22–45% in the first year and 71–136% in the second year after application. The structural carbohydrate content in the mixture depended neither on the biochar dose nor on fertilization. On the other hand, the most significant differences for the studied parameters were observed due to different harvest dates.

Management impacts on organic carbon under continuous perennial grass, perennial grass-legume mixture, and annual cereals on a thick Black Chernozemic soil

Impacts of annual and perennial pasture management on soil organic carbon (SOC) and equivalent SOC stocks (equal soil mass basis) were investigated in two trials [CAESA (1994–1997) and BMP (2008–2012) trials] conducted on the same experimental paddocks at Lacombe, AB. The original site was broken from perennial grass in 1992, and the CAESA trial established in 1993. Between 1994 and 1997, half of the paddocks included winter triticale and a mixture of triticale and spring barley; half included smooth and meadow bromegrass; and each paddock was light, medium, or heavily grazed. The BMP trial (2008–2012) on the same paddocks included fertilized, direct seeded barley as silage; grazing and haying of unfertilized meadow bromegrass, fertilized meadow bromegrass, and meadow bromegrass and alfalfa mixture; and unfertilized oldgrass that was continuous since 1994. Between trials (1998–2007), all paddocks received no fertilizer. In the 0–15 cm depth, SOC under oldgrass was constant between 1994 and 2012 and averaged 88 Mg C ha−1. Under barley silage, SOC decreased from 89 to 72 Mg C ha−1 by 2012. Between 1994 and 2012, SOC decreased in all treatments re-established on original annual forage (1994–1998) but not to the level of barley silage. Light fraction carbon was the highest under oldgrass and the lowest under barley silage. Overall, oldgrass with no fertilizer inputs maintained a constant SOC, although annuals reduced SOC stocks. Re-establishment of perennial grass with grazing may therefore reduce SOC loss, whereas haying perennial grass may not reduce SOC loss.

Effect of preparation based on the bacteria &lt;i&gt;Lactobacillus buchneri&lt;/i&gt; on the productivity of clover and timothy mixture

Relevance and methodology. Legume-grass mixtures are a source of complete feed for dairy cattle due to good digestibility and balance of protein, carbohydrates, amino acids and vitamins. We studied the effect of a microbiological fertilizer («Naturost-Aktiv») based on live microorganisms Lactobacillus buchneri on the productivity and nutritive value of clover and timothy grass mixture. The study was carried out by small-scale field experience in the FSBI «VolSC RAS» (Vologda region) in 2019–2022, as well as in 2021–2022 in the production conditions in the fields of LLC «Zazerkalie» (Vologda region).Results. In the small-plot experiment we showed that under the influence of the microbiological fertilizer treatment, the productivity of clover and timothy grass mixture increased by 7–39% depending on the year of vegetation; the total dry biomass collection for 4 years of the study in the experimental version exceeded the control by 16%. Evaluation of the nutritive value of the grass mixture showed that the fertilizer increased the content of fodder units in dry matter up to 10%, also the content of metabolizable energy, crude and digestible protein, sugars increased slightly and the content of fiber decreased. In the conditions of the production experiment under the influence of the microbiological fertilizer the herbafe collection increased by 10–17%, dry mass — by 9–22%. The nutritive value of the total content of fodder units in 1 kg of biomass in the experiment exceeded the control by 6%. The gross yield of fodder units from 1 hectare of the field increased by 9.6 cwt/ha under the effect of «Naturost-Aktiv».

Yield of lucerne-grass mixtures did not differ from lucerne pure stands in a multi-site field experiment

Changing climatic conditions in north-western Europe require adaptations in management of ley grassland, requiring new grass-legume mixture designs in response to increased variability in precipitation and warmer summers. Evaluation of lucerne (Medicago sativa L.)-grass swards with the grasses cocksfoot (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.), which are potentially more tolerant to summer water shortage, have yet to be evaluated under the agro-climatic conditions of north-western Europe. We tested these grasses in three-species swards and binary lucerne grass swards and compared them against pure stands and a standard lucerne-grass mixture. The study was conducted in eight environments resulting from the combination of four soil sites during the two full main production years 2020 and 2021 with an annual precipitation range of 416–839 mm. Swards were harvested three to five times annually and the accumulated herbage dry matter (DM) and nitrogen (N) yields, as well as species proportions were recorded. We found an average yield of 11.1 t DM ha-1 and no significant differences in herbage DM yields between lucerne pure stands and the different mixture swards. This pattern was stable irrespective of environmental conditions, but in general herbage yield and aboveground N yield were affected by precipitation amount. Swards with cocksfoot had a greater grass proportion than those with tall fescue. The N yield of lucerne-grass swards was lower and declined as the grass proportion increased, and reached on average 353 kg N ha-1. The maximum N yield of lucerne pure stands was 547 kg N ha-1. Species mixtures yielded higher than expected from the pure stands (net mixture effect, NE) pointing at overyielding. Consequently, synergistic interspecific interactions occurred but did not lead to transgressive overyielding. The results indicate that the inclusion of grass species with tolerance to water shortage into lucerne-based swards offers the potential to diversify grasslands without losses of agronomic potential, at least during the first two main production years.

Mixed legume-grass seeding and nitrogen fertilizer input enhance forage yield and nutritional quality by improving the soil enzyme activities in Sichuan, China.

Information regarding relationships between forage yield and soil enzymes of legume-grass mixtures under nitrogen (N) fertilization can guide the decision-making during sustainable forage production. The objective was to evaluate the responses of forage yield, nutritional quality, soil nutrients, and soil enzyme activities of different cropping systems under various N inputs. Alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), orchardgrass (Dactylis glomerata L.), and tall fescue (Festuca arundinacea Schreb.) were grown in monocultures and mixtures (A1: alfalfa, orchardgrass, and tall fescue; A2: alfalfa, white clover, orchardgrass, and tall fescue) under three N inputs (N1: 150kg ha-1; N2, 300kg ha-1; and N3: 450kg ha-1) in a split plot arrangement. The results highlight that A1 mixture under N2 input had a greater forage yield of 13.88t ha-1 year-1 than the other N inputs, whereas A2 mixture under N3 input had a greater forage of 14.39t ha-1 year-1 than N1 input, but it was not substantially greater than N2 input (13.80t ha-1 year-1). The crude protein (CP) content of grass monocultures and mixtures significantly (P < 0.05) increased with an increase in the rate of N input, and A1 and A2 mixtures under N3 input had a greater CP content of 18.91% and 18.94% dry matter, respectively, than those of grass monocultures under various N inputs. The A1 mixture under N2 and N3 inputs had a substantially greater (P < 0.05) ammonium N content of 16.01 and 16.75 mg kg-1, respectively, whereas A2 mixture under N3 had a greater nitrate N content of 4.20 mg kg-1 than the other cropping systems under various N inputs. The A1 and A2 mixtures under N2 input had a substantial higher (P < 0.05) urease enzyme activity of 0.39 and 0.39 mg g-1 24 h-1 and hydroxylamine oxidoreductase enzyme activity of 0.45 and 0.46 mg g-1 5 h-1, respectively, than the other cropping systems under various N inputs. Taken together, growing legume-grass mixtures under N2 input is cost-effective, sustainable, and eco-friendly, which provide greater forage yield and improved nutritional quality by the better utilization of resources.

111 Forage Mass and Nutritive Value of Cool-Season Grass-Legume Mixtures Overseeded into Bahiagrass Pastures

Abstract Warm-season perennial pastures are the base of livestock production systems in lower Alabama. To overcome the shortage in forage production during the late fall and winter months, during bahiagrass dormancy, overseeding pastures with cool-season annuals can be used as an option for providing forage during this period. Diverse forage mixtures of multiple species and functional groups have gained popularity in use among forage-livestock producers, but few evaluations have been conducted in overseeded sods. The objective of the study was to evaluate forage mass and nutritive value of cool-season forage mixtures overseeded into bahiagrass pastures. Six, 0.40-ha paddocks of ‘Pensacola’ bahiagrass were overseeded with one of three cool-season forage mixtures (n = 2 paddocks/treatment) on November2, 2021: 1) oat (Avena sativa), wheat (Triticum aestivum), and balansa (Trifolium michelianum), red (Trifolium pratense), and white clover (Trifolium repens; ‘clovers’); 2) oat, cereal rye (Secale cereale), and clovers; and 3) cereal rye, annual ryegrass (Lolium multiflorum), and clovers. When forage mixtures reached a target grazing height of 20 cm, paddocks were managed using flash mob stocking with beef cow-calf pairs to graze to a target height of0 cm. Herbage mass, nutritive value, botanical composition and height samples were collected pre- and post-grazing events. There was no treatment (P = 0.240) or treatment × harvest (P = 0.4239) effect on forage mass. Harvest date affected (P = 0.029) forage mass, with greater forage mass at late harvest (1,903.33 kg DM·ha-1) than at early (1,253.33 kg DM·ha-1) in the growing season. There were no treatment effects observed for species components (P &amp;gt; 0.05), although grasses dominated the forage mixtures with an average of 80% grass presence. Legume establishment was poor (less than%) and the remaining species composition consisted of weed species (19%). There was a treatment effect (P = 0.003) on CP, where oat-rye-clovers had the greatest CP and rye-ryegrass-clover had the least CP. Oat-wheat-clover mixtures had greater TDN (79.2%), less NDF (39.8%), and ADF (18.7%) than cereal rye-ryegrass-clover (75.4%, 46.1%, and 22.2% for TDN, NDF, and ADF, respectively), but did not differ from oat-cereal rye-clover mixtures (76.6%, 45.7%, 21.0% for TDN, NDF, and ADF, respectively). In year of this study, overseeding bahiagrass supported forage production over a 2-month period and can be a management tool used to reduce the need for supplementing in the dormancy periods of warm season perennial grasses.

The Influence of Nitrogen Applications and Low Rainfall Conditions on Yield of Mixed Grass-Legume Grassland for 2 Years

Mixed-species grassland containing legumes were suggested to increase yield compared to monocultures. Furthermore, some legumes were suggested to be able to sustain growth, even under drought conditions. The first aim of the current study was to measure if multispecies grassland with legumes is also more productive when their N input due to symbiotic N2 fixation is taken into account. Our second aim was to determine the benefit of grass–legume mixtures in terms of dry matter production under naturally occurring drought conditions. Mixed-species grasslands, consisting of monocultures and variable mixtures of (a) Trifolium pratense, (b) Trifolium. repens, (c) Lolium perenne, and (d) a mixture of drought-tolerant grasses (GSWT based), were assessed for their dry matter production over two years with contrasting weather patterns. The legume–grass seeding mixtures received either a fixed (180 kg N ha−1) or adapted N-fertilizer application (0–180 kg N ha−1), with the latter taking the assumed symbiotic N2 fixation by legumes into account. Mixed-species grassland showed improved yield compared to monocultures both in comparably humid and drought-affected years. The benefits of multispecies grass–legume mixtures were considerably more obvious under a fixed but still measurable under an adapted N-fertilizer regime. The species diversity effect appears to be significantly dependent on the additional N supply enabled by legumes’ symbiotic N2-fixation. Legumes and drought-tolerant grasses yielded equally well under drought conditions, although legumes showed major advantages during moderate drought and humid conditions. White and red clover, although both legumes, differed significantly in their persistence under elevated-N and their dry matter production under low-N fertilizer application, but were equal in their tolerance towards drought.

Grass-Legume Mixture with Rhizobium Inoculation Enhanced the Restoration Effects of Organic Fertilizer.

The establishment of artificial grassland is crucial in restoring degraded grassland and resolving the forage-livestock conflict, and the application of organic fertilizer and complementary seeding of grass-legume mixture are effective methods to enhance grass growth in practice. However, its mechanism behind the underground is largely unclear. Here, by utilizing organic fertilizer in the alpine region of the Qinghai-Tibet Plateau, this study assessed the potential of grass-legume mixtures with and without the inoculation of Rhizobium for the restoration of degraded grassland. The results demonstrated that the application of organic fertilizer can increase the forage yield and soil nutrient contents of degraded grassland, and they were 0.59 times and 0.28 times higher than that of the control check (CK), respectively. The community composition and structure of soil bacteria and fungi were also changed by applying organic fertilizer. Based on this, the grass-legume mixture inoculated with Rhizobium can further increase the contribution of organic fertilizer to soil nutrients and thus enhance the restoration effects for degraded artificial grassland. Moreover, the application of organic fertilizer significantly increased the colonization of gramineous plant by native mycorrhizal fungi, which was ~1.5-2.0 times higher than CK. This study offers a basis for the application of organic fertilizer and grass-legume mixture in the ecological restoration of degraded grassland.

Impacts of two years of autumn cover crops in northwestern Washington on winter annual weed populations

AbstractCover cropping is a suggested soil conservation practice widely investigated in cropping systems. Cover crops suppress weeds and often are part of an integrated weed management plan that could lead to reduced herbicide use and possibly reduce the weed seedbank. Winter brassica cover crops are popular in the eastern Washington potato (Solanum tuberosum L.) production region, but in western Washington, the production of brassica seed crops presents disease issues along with the risk of cross-pollination, which limits the use of brassica cover crops. Research for this article was conducted in two trials from 2018 to 2020 and 2019 to 2021in Mount Vernon, Washington, to identify winter cover crops compatible with regional restrictions and climatic challenges in western Washington cropping systems. Treatments including a no-cover control, eight single species (including brassicas, grasses, and legumes), and a grass–legume mixture were investigated. Cover crop and weed biomass production were measured, and percent ground cover for cover crops and weeds by species was estimated. Cover crop biomass and weed suppression varied by year due to variable environments, but annual ryegrass (Lolium multiflorum Lam.) and the mixture were most consistent in producing large amounts of biomass and reducing weed biomass and cover in all years. The variability of percent weed cover response to environment was ameliorated when weed cover was normalized within each year’s control.

The Effect of Molybdenum Fertilizer on the Growth of Grass–Legume Mixtures Related to Symbiotic Rhizobium

Molybdenum (Mo) is required by the enzymes involved in many metabolic processes related to plant growth and development. However, the effects of Mo addition on plant growth and beneficial microorganisms in mixed grasslands are unclear. We conducted a greenhouse experiment to examine the effects of different Mo addition levels (10 and 20 mg Mo kg−1 soil in the form of Na2MoO4) on the growth of perennial ryegrass–white clover in two low-Mo soils, as well as their symbiotic microorganisms. Our results showed that the addition of Mo had a significant impact on plant growth in limestone soil but not in yellow loam soil (p &lt; 0.05). Compared with no addition of Mo fertilizer in limestone soil, an addition of 10 mg Mo kg−1 significantly increased the plant community shoot and root biomass (p &lt; 0.05). However, this improvement was not observed with an addition of 20 mg Mo kg−1. The shoot nitrogen and phosphorus content in both soil types was unaffected by the Mo addition (p &gt; 0.05), whereas the 10 mg Mo kg−1 addition significantly increased the shoot nitrogen and phosphorus uptake in limestone soil (p &lt; 0.05). This increase in plant community productivity was primarily due to the increased growth of both species, caused by the enhanced activation of the symbiotic rhizobium. We conclude that Mo supply may promote N utilization and uptake in mixed grassland by increasing the activity of symbiotic rhizobium, resulting in a higher yield of mixed grassland, which is critical for sustainable agricultural development in low-Mo soils.

Response of Organic Fertilizer Application to Soil Microorganisms and Forage Biomass in Grass–Legume Mixtures

It has been widely recognized that organic fertilizer (OF) application under monoculture and continuous cropping can change the microbial community and increase forage biomass in the Qinghai–Tibet Plateau. However, as a commonly used grassland planting pattern, the way in which grass–legume mixtures respond to OF application remains unclear. To clarify application effects of organic fertilizer in the grass–legume mixtures, we conducted a field experiment at the Qinghai–Tibet Plateau and collected the rhizospheric and bulk soils to reveal their microbial community by using high-throughput sequencing and molecular ecological networks. It was found that OF application changed the microbial community and increased the forage biomass under monoculture. However, in grass–legume mixtures, we found that OF application did not promote the increase of forage (Gramineae) biomass (Student t-test: p &gt; 0.05). By analyzing both prokaryote and fungal communities, it was found that OF application had a greater impact on bulk soil microorganisms than on those of the rhizosphere in grass–legume mixtures. Co-occurrence network analysis showed that the rhizosphere and bulk soil networks of grass–legume mixtures were significantly more vulnerable under OF treatment (vulnerability of prokaryotes in grass: 0.1222; vulnerability of prokaryotes in legumes: 0.1730; fungal vulnerability in grass: 0.0116; fungal vulnerability in legumes: 0.0223) than non-OF treatment (vulnerability of prokaryotes in grass: 0.1015; vulnerability of prokaryotes in legumes: 0.1337; fungal vulnerability in grass: 0.0046; fungal vulnerability in legumes: 0.0126), which indicated that OF application did not provide favorable conditions for microbial interactions in grass–legume mixtures. In addition, structural equation modeling showed that OF application had some significant negative impacts on soil physicochemical properties and the robustness of the prokaryote community. The robustness of fungi had a significant negative (p &lt; 0.001) impact on forage biomass, but OF application had no significant (p &gt; 0.05) direct impact on the forage biomass, which indicated that the OF did not promote forage biomass in grass–legume mixtures. These results suggest that the application of organic fertilizer is unnecessary for grass–legume mixtures, because it does not promote the interactions between rhizospheric microbes and forage.

A grass–legume cover crop maintains nitrogen inputs and nitrous oxide fluxes from an organic agroecosystem

AbstractLegume cover crops are central to an ecological nutrient management approach that can reduce nitrogen (N) losses from agriculture. Diversifying cropping systems with a legume–grass cover crop mixture could further reduce N losses by increasing soil N assimilation and synchronizing N mineralization with N uptake by the following crop. We established four winter cover crop treatments (crimson clover, cereal rye, clover–rye mixture, and weedy fallow control) in an organic grain agroecosystem that had been managed for 30 years with a legume cover crop as the only external N source. We hypothesized that the legume–grass mixture would provide similar inputs of biologically fixed N2 compared with the sole legume, while reducing N2O emissions during decomposition following tillage. We measured cover crop aboveground biomass C:N and clover N2 fixation, soil inorganic N and N2O fluxes throughout the corn growing season following cover crop tillage, and corn N assimilation at harvest. Even with a reduced clover seeding rate in mixture, the clover and mixture treatments had similar fixed N inputs, litter N and C:N, and no differences in cumulative N2O emissions. During the first peak flux, N2O emissions were 2–5 times higher in clover and mixture relative to rye and fallow, with no differences between clover and mixture. There were no treatment differences at the second N2O peak, which followed the first major rain event. We contextualized these findings by calculating a 6‐year partial N mass balance for this agroecosystem, which was slightly negative (−6.8 ± 0.8 kg N ha−1 year−1) when accounting for historical mean annual N2O emissions and nitrate leaching. Overall, N inputs and harvested N exports were approximately in balance for this legume‐based crop rotation, suggesting that the legacy of ecological nutrient management has promoted efficient N cycling. However, results from our field experiment indicate that short‐term N2O flux rates following cover crop incorporation can be high even for a legume–grass mixture. Additional strategies to reduce soil disturbance are therefore needed to further tighten N cycling in organic grain agroecosystems.

Grass-legume mixture and nitrogen application improve yield, quality, and water and nitrogen utilization efficiency of grazed pastures in the loess plateau.

Grazing on cultivated grassland is a green agricultural model. However, in China's Loess Plateau, the type of cultivated grassland suitable for grazing and the amount of nitrogen application is still unclear, which has led to the failure of this model to be widely implemented. In this context, we set up an experiment using three grass planting types, including monoculture of alfalfa (Medicago sativa L.), monoculture of brome (Bromus inermis L.), and mixed planting of the two forages. Under each planting type, there were six management measures: grazing and no nitrogen application (GN1), grazing and 80 kg ha-1 nitrogen application (GN2), grazing and 160 kg ha-1 nitrogen application (GN3), cutting and no nitrogen application (MN1), cutting and 80 kg ha-1 nitrogen application (MN2), and cutting and 160 kg ha-1 nitrogen application (MN3). To explore the impacts of these treatments on pastures, we studied the effects on the yield, quality, and water use efficiency of the three cultivated grasslands. Results showed that alfalfa monoculture and alfalfa-brome mixed sowing grassland resulted in significantly higher hay yield, crude protein yield, water use efficiency (WUE), precipitation use efficiency (PUE), nitrogen use efficiency (NUE), and agronomic efficiency of nitrogen (AEN) as compared to brome monoculture grassland. In addition, the crude protein, ether extract, and crude ash content of alfalfa monoculture and alfalfa-brome mixture were increased significantly while the contents of neutral detergent fiber (NDF) were reduced, thereby increasing the relative feed value (RFV) during the two years. The forage hay yield, crude protein yield, ether extract, crude ash content, RFV, PUE, and WUE were significantly higher with GN1, GN2, and GN3 treatments than that with MN1 treatment. In contrast, the NDF and acid detergent fiber (ADF) content was significantly lower than the MN1 treatment. Furthermore, the fresh forage yield, crude protein yield, PUE, and WUE of GN3 treatment were significantly higher than that of GN1 and GN2 treatments in both years, while the NUE and AEN were significantly higher in GN2 and GN3 treatments than that of MN3 treatment. Based on these results, alfalfa-brome mixed cropping with the application of 160 kg ha-1 nitrogen under grazing conditions is an appropriate management practice for improving the forage yield, quality, and water- and nitrogen utilization efficiency of cultivated grassland in the Loess Plateau of China. This integrated management model is applicable to the cultivation and utilization of mixed grassland on nutrient-poor land in the Loess Plateau.

ҚАЗАҚСТАННЫҢ СОЛТҮСТІК ӨҢІРІНДЕГІ ЖАЙЫЛЫМДАРДЫ ЖАҚСАРТУ ҮШІН ДӘНДІ-БҰРШАҚТЫ ШӨП ҚОСПАЛАРЫН ЗЕРТТЕУ

The article shows the data obtained from the study of the productivity of multispecies agrophytocenoses in the conditions of the northern region of Kazakhstan. The research methodology and findings of field experiments dedicated to the utilization of grass-legume grass mixtures to enhance pasture productivity in the northern region are detailed in this paper. It contains the meteorological data for the 2023 growing season in the northern region. The research involved agrochemical soil analyses, monitoring the density and height of the cereal-legume grass mixture, mowing and weighing, classifying the composition of the grass mixture by species, and drying bundles to reach air-dried state in order determine the productivity. The photosynthetic activity of plants was assessed by measuring chlorophyll content using the N-tester SPAD 502 Plus Chlorophyll Meter, a tool designed for on-site evaluation of plant nitrogenous nutrition based on chlorophyll content in leaves. In summary, the study suggests that selecting grass-legume mixtures with high productivity and nutritional value, adapted to the soil and climatic conditions of the northern region of Kazakhstan, is crucial for restoring pasture productivity.

Selection of inter-row herbaceous covers in a sloping, organic, non-irrigated vineyard.

Inter-row vegetation in vineyards is classified as a service crop as it provides many ecosystem services. The vegetation is often removed but maintaining them can mitigate the negative effects on the environment. However, the type of species or mixture choice can affect their success. A field trial was conducted in an organically-managed vineyard of Cabernet sauvignon Vitis vinifera L. cultivars in north-eastern Italy, in which three blends of grass species (Shedonorus arundinaceus, Lolium perenne and Festuca rubra) and two grass-legume mixtures were grown in the inter-rows and compared with resident vegetation and regularly tilled bare soil. Each vegetation type, including resident vegetation, was subjected to mulching and non-mulching treatments. The aim of this study was to evaluate the use of seeded species or mixtures in the inter-row spaces of the vineyard in north-Italy as an alternative management to resident vegetation and tilled soil. The experiment was conducted over two years to monitor the persistence of the sown vegetation and the influence of vegetation types on vine performance and grape composition, and on soil compaction and erosion. The relative abundances of each species, vegetation height, percentage green cover and normalised difference vegetation index (NDVI), vine shoot length, number of leaves per vine shoot, leaf area, bunch weight, vine NDVI, soil compaction and erosion, and depth and width of tractor tyre prints were measured. Over time, weed invasion altered the botanical composition of all vegetation types except for the S. arundinaceus blend, which remained stable throughout the study period. Our results showed that vine parameters were not affected by the type of vegetation in the inter-rows, nor were there differences between the grassed and bare soil inter-rows. Soil compaction and erosion, and tractor tyre prints were not directly affected by the type of vegetation cover, but they were affected by tillage in the plots with bare soil in the inter-rows or where it was used to prepare the soil for sowing. Soil compaction and erosion were related to the percentage vegetation cover. Mulching did not affect any of the parameters measured. Therefore, species selection plays a crucial role in inter-row vegetation management and in minimising environmental impacts. S. arundinaceus gave high protection against soil erosion due to its high persistence throughout the year and had the lowest growth rate thus requiring fewer cuttings.

Integrating Native Plant Mixtures and Arbuscular Mycorrhizal Fungi Inoculation Increases the Productivity of Degraded Grassland

Intense human activities break the grassland–livestock balance and accelerate grassland degradation. We evaluated the use of native dominant species combined with arbuscular mycorrhizal fungi (AMF) in order to recover grassland and restrain grassland degradation. We conducted a full factorial greenhouse experiment to evaluate the interaction effects of native species of distinct traits grass Lolium perenne (L) and legume Trifolium repens (T) with arbuscular mycorrhizal fungi (AMF) inoculation on grass productivity and soil properties across non-degraded, lightly degraded, and severely degraded soils. The grass–legume mixture was manipulated with five ratios (T:L = 1:0, T:L = 1:1, T:L = 3:1, T:L = 1:3, T:L = 0:1). The results showed that L. perenne significantly increased grassland productivity at different grass–legume ratios, regardless of AMF presence or absence. AMF inoculation increased plant N and P content uptake and improved the productivity of degraded grasslands, especially in severely degraded grasslands. The NO3−-N and available P concentrations increased in soil when the legume component increased from T:L = 0:1 (grass monoculture) to T:L = 1:0 (legume monoculture). This may be because the presence of Lolium perenne (L) can promote nitrogen fixation in legumes. Structural equation modeling indicated that grass–legume mixtures directly affected plant biomass, whereas AMF affected plant biomass via providing plant nutrients. A soil quality index based on minimum datasets indicated a significant positive effect of artificial grassland establishment on soil quality. We conclude that planting T:L = 0:1 and T:L = 1:3 combined with AMF inoculation can be used to recover degraded grassland production, and planting T:L = 1:1 and T:L = 1:3 plus AMF inoculation can be applied for grassland nutrient accumulation and stability maintenance.