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[Objective] The study aimed to explore the effects of four weed populations on apple photosynthetic characteristics and fruit quality formation, and screen out suitable grass for planting in Zhaotong orchards. [Method] We conducted a field experiment with Fuji apples and set orchard clear-cutting as the control, and explored the effects of Artemisia absinthium(Artemisia lavandulaefolia DC), Artemisia stellate (Stellaria vestita Kurz.), Ryegrass (Lolium perenne L.) and White-flowered cheatgrass (Trifolium repens Linn) on the leaf chlorophyll content, photosynthetic characteristics and fruit quality of the fruit trees. [Result] White-flowered cheatgrass treatment could increase leaf total chlorophyll content, net photosynthetic rate (P), intercellular CO₂ concentration (C₁), stomatal conductance(G) and carboxylation efficiency (CE), while the water use efficiency (WUE) of the fruit trees was significantly reduced. The Artemisia absinthium treatment could increase leaf G, and improve C, to a certain extent, but it would reduce the total chlorophyll content and leaf CE. Artemisia stellate treatment could increase C, and the total chlorophyll content as well as leaf transpiration rate (T,) were reduced. Ryegrass treatment significantly increased WUE and CE, but significantly reduced T. Quality aspect, the various raw grass treatments increased fruit solids content by 0.88% 13.87%, reduced reducing sugar content by 2.30% 15.71%, increased total antioxidant capacity by 10.03%-40.92%, and the ryegrass treatment reduced hydrogen peroxide content by 41.80% and superoxide anion scavenging capacity by 12.92%, as compared to clear tillage. Using fuzzy membership function analysis, the comprehensive evaluation value of clear tillage, white clover, mugwort, stellaria and ryegrass were 0.4858, 0.6044, 0.5548, 0.4894 and 0.6059, respectively. [Conclusion] Different weed populations can improve the photosynthetic capacity of fruit leaves and improve fruit quality to a certain extent. Scientific evaluation of four weed populations is beneficial to screen out more reasonable grass types in orchards. [ABSTRACT FROM AUTHOR]

Aims: To develop a methodology to study uptake and redistribution by plants of NH4+ from deep soil, applying it to investigate deep root N uptake by cultivated grassland species. Methods: A slow-release 15NH4+ label adsorbed to clinoptilolite was placed into soil (depth 42 cm) well below the densest root zone in well-established monospecific stands of five grass and two clover species. Species showing a variety of deep rooting patterns, N acquisition strategy, forage qualities, and persistence in hemiboreal conditions were chosen. The label was placed in early spring and tracked throughout one or two growing seasons in two repeated experiments. Results: After two growing seasons ~ 90% of the label was tracked in the soil and harvested herbage of grasses, less in clovers. Deep N uptake was limited in spring, increased during mid-season, and was strongest in autumn in all species, despite lower herbage yield in autumn. Species differed in ability to recover and maintain 15N in the soil–plant system. In one growing season, Lolium perenne L., Phleum pratense L., Schedonorus pratensis (Huds.) P.Beauv. and Schedonorus arundinaceus (Schreb.) Dumort herbage recovered ~ 65% of the label, Poa pratensis L. 54%, and Trifolium pratense L. and Trifolium repens L. 36–48%. Label transport to topsoil was observed, mainly attributable to plant nutrient redistribution rather than physical diffusion. Conclusions: The innovative slow-release 15N label enabled tracing species differences and seasonal changes in uptake of NH4+ from deep soil. Among the tall-growing grasses, growth vigor appeared as important for deep N uptake as expected root depth. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify the farm gate nitrogen (N) offset potential of perennial ryegrass (Lolium perenne L.; PRG) white clover (Trifolium repens L.; WC) swards by comparing the herbage and milk production from dairy farmlets that were simulations of full farming systems. A study was established where 120 cows were randomly assigned to 4 farmlets of 10.9 ha (stocking rate: 2.75 cow/ha), composed of 20 paddocks each. Cows were fed 526 kg of DM of concentrate on average each year. The 4 grazing treatments were PRG-only at 150 or 250 kg of N/ha and PRG-WC at 150 or 250 kg of N/ha. Cows remained in their treatment group for an entire grazing season and were re-randomized as they calved across treatments each year. As cows calved in the spring as standard practice in Ireland, they were rotationally grazed from early February both day and night (weather permitting) to mid-November, to a target postgrazing sward height of 4.0 cm. Mean sward WC content was 18.1% and 15.4% for the 150 and 250 kg of N/ha PRG-WC treatments, respectively over the 3-yr period. When WC was included, lowering the N rate did not reduce pregrazing yield, pregrazing height, or herbage removed, but those factors decreased significantly when WC was absent. Total annual herbage DM production was 13,771, 15,242, 14,721, and 15,667 kg of DM/ha for PRG-only swards receiving 150 or 250 kg of N/ha and PRG-WC swards receiving 150 or 250 kg of N/ha, respectively. In addition, when WC was present, compressed postgrazing sward heights were lower (4.10 vs. 4.21 cm) and herbage allowance (approximately 17 kg/cow feed allocation per cow per day) higher than the high-N control (+ 0.7 kg of DM/cow per day). There was a significant increase in milk production, both per cow and per hectare, when WC was included in PRG swards. Over the 3-yr study, cows grazing PRG-WC had greater milk (+304 kg) and milk solids (+31 kg of fat + protein) yields than cows grazing PRG-only swards. This significant increase in milk production suggests that the inclusion of WC in grazing systems can be effectively used to increase milk production per cow and per hectare and help offset nitrogen use. This result shows the potential to increase farm gate N use efficiency and reduce the N surplus compared with PRG-dominant sward grazing systems receiving 250 kg of N/ha, without negatively affecting milk solids yield or herbage production, thus increasing farm profit by €478/ha. [ABSTRACT FROM AUTHOR]

Aim. Develop a Life Cycle Analysis (LCA) in livestock farms with rotational management of the pasture according to botanical composition. Materials and methods: Dairy farms from Cotopaxi, at 2800-3590 meters above sea level, were compared. Farm 1: load of 1 and 1.2 AU/ha, with 50% Plantain (Plantago lanceolata), 50% White Clover (Trifolium repens). Farm 2: Load of 1 and 1.2 AU/ha, 85% Ryegrass (Lolium perenne)-15% White clover (Trifolium repens). Farm 3: Load of 1 and 2.1 AU/ha, 33% Ryegrass-33% Plantain-34% White Clover. Fertilization, balancing and crossbred, New Zealand and North American type Holstein animals and grass rest were used. Results: There were differences in land use, coinciding in farms 1 and 3, in family labor. On Farm 1, rest was 15 to 28 days and NDF from 47.38 to 28.03 and 1.96 to 2.45 Mcal of energy and in 3, Metabolizable Energy values from 1.99 to 40 days and 2 .11 to 35 days, less milk/cow than 3 and higher than 1. In milk production/ha, farms 1 and 3 higher with 24 kg vs 19 kg. This was positive for ACV on those farms. There was potential to convert more of the system's energy into products. Conclusion: In the LCA, a coincidence was found with indicators of specialized systems in milk production, nitrogen balances, energy and their relationships with the environment and emissions, although efficiency can be recovered with improvements in management and without extra inputs to the farm. [ABSTRACT FROM AUTHOR]

Aims: Mixed communities of plant species with different functional traits or microbial associations can more fully utilize soil nutrient pools. However, there is a gap in our understanding of the synergistic influences of arbuscular mycorrhizal (AM) fungi in nutrient capture and resource partitioning across different soil depths in mixed plant communities, as well as their possible effects on plant coexistence. To address these knowledge gaps, we assessed the effect of AM fungi on nutrient uptake and competition between shallow- and deep-rooted pairs of grass and legume species. Methods: To quantify the mycorrhizal mediation of N uptake at different soil depths, 15N tracer was injected into soil at 3- and 25-cm depths of microcosms planted with monoculture or bi-species mixtures, with or without AM fungi. Results: AM symbioses reduced plant competition by equalizing access to N and subsequently increasing shoot N and P concentrations of plant species on mixed communities. Niche differentiation had minimal effects on grass and legume competitive interactions. Both deep-rooted plant species, i.e., Medicago sativa and Dactylis glomerata, and shallow-rooted species, i.e., Lolium perenne and Trifolium repens, primarily acquired nutrients from shallow soil layers. However, AM fungi significantly enhanced nutrient uptake and facilitated N2 fixation in legumes at 3 and 25 cm soil depths. Conclusion: Our results suggest AM fungi strongly influence host-plant competitiveness and vertical nutrient capture in mixed plant communities, underscoring that microbial mutualist-mediated nutrient acquisition is a key driver of gains in productivity of grass–legume mixtures. [ABSTRACT FROM AUTHOR]

The local abiotic and environmental conditions of a grass‐based farming system may influence the agricultural benefits of mixtures in comparison to pure stands. We investigated the effects of species identities and interactions between grass, legume, and herb species on dry matter yield and sward digestibility and explored how contrasting environments may affect these relationships. We established experimental plots across 11 mixtures and 4 monocultures of perennial ryegrass (Lolium perenne L.), chicory (Cichorium intybus L.), white clover (Trifolium repens L.), and red clover (Trifolium pratense L.) established at two seeding densities in two sites Brody and Szelejewo (Poland) and managed them over a 3‐year period. The two sites were close geographically and had similar climates, but differed in soil types (Luvisols and Cambisols, respectively). We confirmed that the annual DM yields were generally higher on Cambisols soil as compared to Luvisols soil; both individual species effects and species interaction strengths differed across the two contrasting environments. The predicted annual DM yield for the 4‐species mixtures in general gave comparable or higher yields compared to monocultures across the 3 years, with the mixtures giving around 10%–30% higher yields than the weighted average of the monocultures of the constituent species. Analysing the transgressive overyielding it turned out that there was no significant difference between the 4‐species mixtures and best performing monoculture. The benefits of species diversity in our study was greater on less productive site because we found larger overyielding of the 4‐species sward on the Luvisols soil than on the Cambisols soil. Additionally, the effect of mixtures composed by 4‐species increased the yield stability compared to monocultures in the 3‐year period of our study, particularly on Cambisols soil. Sward digestibility applied to average values did not differ much between sites with mixtures performing similarly to monocultures. The reason for that could have been the dynamics of sward botanical composition during study years shifted towards increased perennial ryegrass and decreased proportions of chicory in the sward as well as the observed phenomenon that the species in mixed swards progressed to successive growth stages more slowly than in pure sowing. [ABSTRACT FROM AUTHOR]

Context: Tagasaste (Cytisus proliferus), a fast-growing leguminous tree, has potential to supplement pasture production in steep-hill country and to increase pasture resilience. Aims: In the companion paper, we quantified tagasaste production characteristics. Here, we determine the effect of proximity of 10-year-old tagasaste trees on productivity of eight pasture species including grasses (perennial ryegrass, Lolium perenne ; cocksfoot, Dactylis glomerata ; prairie grass, Bromus willdenowii ; microlaena, Microlaena stipoides), perennial legumes (white clover, Trifolium repens ; red clover, T. pratense ; lotus, Lotus pedunculatus), and an annual legume (subterranean clover, T. subterraneum). Methods: A site was established in the East Coast region of the North Island of New Zealand on steep-hill country (>20° slope). Herbage production, nutritive value and survival of pasture species established as spaced transplants were measured over 3 years. Results: Cocksfoot had high survival, herbage production and metabolisable energy content but was negatively affected by proximity to tagasaste. Microlaena was not significantly affected by proximity to tagasaste; however, it was much less productive and had lower nutritive values than the other grasses. Only 40% of perennial ryegrass transplants survived 3 years, and survival of perennial legumes was negligible. Subterranean clover was able to set seed in the open and in shade. Conclusions: Cocksfoot was the most productive grass species, and microlaena was least affected by proximity to tagasaste. Given the poor persistence of perennial clovers, annual clovers may be better suited to a tagasaste silvopasture on steep, dry hillsides. Implications: Mixtures of cocksfoot and subterranean clover may be well suited to summer-dry hillsides, between and under trees in a tagasaste silvopasture. Microlaena may provide some forage and can maintain groundcover despite shade. Growth and survival of eight pasture species in proximity to the forage shrub tagasaste were quantified in drought-prone hill country. Cocksfoot and subterranean clover were highly productive only in lightly shaded areas, whereas microlaena, although less productive than other grasses, was not significantly affected by shade treatment, and perennial legumes showed negligible survival. Cocksfoot and subterranean clover could be established between trees in a tagasaste silvopasture, with naturalised microlaena maintained beneath the canopy to provide groundcover. [ABSTRACT FROM AUTHOR]

International seed trading provides a significant introductory pathway for weed seeds, and many globally established weeds originated as contaminants in agricultural seed lots. Management of these trade systems helps minimize agricultural losses and is an important means of preventing future biological incursions. Forage crop seed lots could be considered higher risk than seed lots of arable and vegetable crops, as they have been found to have a higher percentage of contaminated seed lots. Two of the most commonly used temperate forage crops worldwide are perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). New Zealand is one of the top producers of these crop seeds globally, and both species are commonly used in New Zealand pastures. Using historical and current seed lot analytical purity test results, we examined the frequency, identity and temporal changes of weed seeds found within agricultural seed lots of perennial ryegrass and white clover grown in New Zealand from 1912 to 2019. Overall, the percentage of contaminated forage seed lots decreased between approximately three to sixfold over the study period, indicating that herbicide availability, seed certification and improved crop management have been effective for weed control. However, we identified a handful of annual weed species that could become more problematic in the future, either because they showed an increasing presence trend in seed lots or were identified as the most common contaminants. In 2019, Vulpia bromoides was the most common contaminant in perennial ryegrass seed lots, and Chenopodium album was the most common in white clover seed lots. Sherardia arvensis and Poa annua, both significant species with an increasing presence trend, had the largest increases in perennial ryegrass seed lots over the study period. Conversely, Rumex acetosella had the largest presence decline for both crop species. There was a significant difference between the percentage of contaminant species that were grass weeds between study crops, where perennial ryegrass seed lots had approximately four times more grass species than white clover. Considering New Zealand trades crop seed with approximately half of the world's countries and contributes substantially to the global supply of forage seed, our study provides a unique insight into changes of the weed spectrum throughout the seed for sowing system over the last century. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Simple Summary: We observed a forage allowance by forage type effect on improvements in the daily milk yield of dairy cows grazing swards sown with perennial ryegrass, white clover and plantain relative to those sown to perennial ryegrass only. Improvements in milk yield were evident at lower forage allowances of 14 to 20 kg of dry matter/cow per day (inclusive), diminishing at the highest allowance of 25 kg of dry matter/cow per day. At the lower forage allowances, energy intake would have been a limiting factor for milk production, potentially highlighting the nutritive advantages of plantain and white clover. Increasing species diversity is a possible strategy for overcoming seasonal nutritive challenges present in perennial ryegrass monocultures. We tested for a forage allowance effect on the milk yield of early lactation dairy cow herds grazing swards sown with perennial ryegrass (Lolium perenne L.), white clover (Trifolium repens L.) and plantain (Plantago lanceolata L.) relative to perennial ryegrass alone. The examined allowances consisted of offering 12, 14, 16, 18, 20 or 25 kg of dry matter (DM)/cow per day of grazeable herbage, with diverse swards sown as mixtures and spatially adjacent monocultures. After adapting cows to their assigned forage type for 8 days, treatment effects on milk yield and composition, blood metabolites (beta-hydroxybutyrate, non-esterified fatty acids and urea concentrations), body weight change, forage intake and selection differentials for forage species and certain nutrients were monitored over 7 days. We confirmed a forage allowance effect on milk yield improvements in dairy cows grazing diverse swards relative to perennial ryegrass monocultures. Improvements in milk yield were evident at forage allowances of 14 to 20 kg of DM/cow per day, diminishing at the highest allowance of 25 kg of DM/cow per day. Improvements in milk yield for the mixture and spatially adjacent monocultures peaked at forage allowances of 18 and 16 kg of DM/cow per day, equalling increases of 1.3 and 1.2 kg of milk/cow per day, respectively. [ABSTRACT FROM AUTHOR]

Trifolium repens (white trefoil) is an important perennial leguminous species from permanent and artificial pastures. White trefoil is usually cultivated in mixture with a grass species, respectively Lolium perenne because they are forming together a balanced source of forage from nutritional point of view. The research analyses the variation of the seasonal growth of Trifolium repens and Lolium perenne in pure stands and as mixture in the conditions of grazing with sheep and cutting. The research was performed at Research and Development Station for Sheep and Goats Breeding Caransebeș on an albic luvisol, pseudo-gleyic, low acid, moderate provisioned with phosphorus and potassium. The formation, growth and development of Trifolium repens stolons was assessed at every grazing cycle and after every cut. Also, there was assessed the plant height before every cutting or grazing cycle. The experimental factors considered were exploitation mode (cutting, grazing 2 LU/ha and 4 LU / ha) and distance between rows at seeding (12.5 and 25 cm). The assessed features for Trifolium repens were: length of the stolons per plant, number of nodes per stolon and the distance between two nodes per 10 plants from each replicate. Distance between rows hasn’t been influenced by the analysed stolons features. Also, once with the increase of the nodes number decreases the length of an internode, these two features of the stolons being corelated negatively. [ABSTRACT FROM AUTHOR]

Drought can induce phenotypic plasticity in a range of plant root and shoot traits. These traits have been shown to explain differences in root and shoot litter decomposability between species. However, it is unknown how drought‐induced plasticity of root and shoot traits alters their decomposability.To investigate this issue across a range of species, we grew a grass Lolium perenne, a forb Plantago lanceolata and a legume Trifolium repens common to European temperate grasslands and subjected them to a 5‐week moderate drought treatment. We compared morphological and chemical root and shoot traits of the droughted plants to well‐watered controls. We then conducted a decomposition assay of the senesced root and shoot material over 16 weeks, with mass loss measurements at five timepoints.Drought had significant and sometimes strong effects on morphological and chemical root and shoot traits of all three species, sometimes similar to differences between species and generally in line with a shift to a more resource‐conservative strategy. Drought also increased the labile litter fraction in roots of Lolium perenne, which was associated with a substantial increase in non‐structural carbohydrates. Drought decreased the labile litter fraction in shoots of Plantago lanceolata, but this could not be explained by the traits we measured. Drought effects on litter decomposability were weaker than on plant traits.Our results suggest that plant trait‐mediated effects of drought on litter decomposability can either increase or decrease vegetation feedbacks to climate change. They also show that drought‐induced plasticity in root and shoot traits does not automatically translate into equivalent changes in litter decomposability. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The expanded usage of white clover has increased the importance of understanding white clover dynamics in pastures. It is assumed that clover plants have a higher tolerance for moisture and nutrient deficiencies when the taproot is still present. Therefore, the survival of the seminal taproot can influence the dynamics of clover. Past breeding efforts in countries like New Zealand have focussed on increasing the taproot longevity through hybridisation with a close relative of white clover. However, there is no direct evidence whether increased survival of the taproot results in increased performance of white clover. In this study, we aimed to (i) assess the relationship between taproot volume and taproot survival, and (ii) whether the timing of death of the seminal taproot influences the population dynamics of white clover varieties. In a two‐year field experiment with 18 white clover varieties grown in monoculture and in mixture with Lolium perenne L, the taproot characteristics and population dynamics were studied. It was shown that taproot volume was positively correlated to both leaf size and taproot presence during autumn 2017, 1 year after sowing. The combination of the timing of death of the seminal tap root and the development of stolons seems to play a more important role in increasing the persistence of white clover than the absolute survival of the seminal taproot. Future research should focus on understanding the transition from a taprooted white clover to a stolonous white clover plant in relation to specific weather events such as winter frost conditions. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (PRG, Lolium perenne L.) breeding effort in New Zealand (NZ) has increased since c. 1990, resulting in greater functional trait diversity (e.g. heading date, ploidy, and associated Epichloë endophyte strain) in commercial products. This study quantified the variation, associations and interactions in dry matter (DM) yield, nutritive value and persistence‐related traits among commercial cultivar‐endophyte combinations released between 1973 and 2012, as a basis for assessing gains in value being delivered to the pasture‐based livestock industries. Twenty‐four or 28 combinations were compared over 3 years in two trials in each of two regions: Waikato in northern NZ (dryland), and Canterbury in central eastern South Island (irrigated). Cultivar‐endophyte combinations were sown in mixtures with white clover, and pastures were intensively grazed 8–11 times per year by dairy cows. Principal Component Analysis identified 4 distinct clusters for the DM yield variables and for metabolisable energy (ME) content in each of the four trials. A broadly‐adapted group of three late‐season flowering, AR37‐infected diploids with NZ and Spanish breeding backgrounds dominated the highest‐yielding clusters. Tetraploids dominated the high ME content clusters. Interactions with region were observed throughout the data set: the strongest of these was driven by endophyte strain effects in Waikato. High‐yielding cultivar‐endophyte combinations in these trials were also generally high‐yielding in the standard cultivar merit testing system operated in New Zealand, as interpreted via the DairyNZ Forage Value Index. However, alignment was poorer for medium‐ and lower‐yielding cultivar‐endophyte combinations. Several implications for forage evaluation methods and end‐user industries are identified. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the amount of crude protein yield and the yield of feed units in the fodder biomass of six variants of two-component legume-grass mixtures (Lotus corniculatus- Festuca rubra; Trifolium repens - Lolium perenne; Trifolium repens - Poa pratensis; Trifolium pretense - Phleum pretense; Medicago sativa - Dactylis glomerata; Trifolium pretense - Festuca pratensis) that would provide high-quality fodder in the conditions of the Central Balkan Mountain. The highest crude protein yield is for the mixtures Tr. pratense L. + F. pratensis L. and Tr. repens L. + P. pratensis L. The legume crop predominated in the regrowths of both variants during the entire experimental period from 7.4% to 48.4%, respectively, and the ratio of legume:grass in the mixed grass stands was 47.7:40.3% (Tr. pratense L. - F. pratensis L.) and 62.3:13.9% (Tr. repens L.- P. pratensis L.). A proven difference in crude protein yield was found between Tr. repens L. - P. pratensis L. and M. sativa L. - D. glomerata L. mixtures. The highest yield of feed units for milk and growth was found in the forage mixture of Tr. pratense L. with Ph. pratense L. [ABSTRACT FROM AUTHOR]

Purpose: Belowground carbon (C) allocation for nitrogen (N) acquisition plays a crucial role in determining primary productivity and plant competitiveness in legume-grass mixtures, but beyond modeling and qualitative assessments, this remains poorly understood, especially with regard to drought stress and interspecific interactions. Methods: We grew a legume (Trifolium repens) and a grass (Lolium perenne) in monocultures and as a 50:50 mixture (with same plant density), at 70% and 50% soil water holding capacity representing non-drought and drought conditions, for 104 days in a growth chamber experiment. By using continuous 13CO2 labelling and 15N pulse soil-labelling, we analyzed how drought and interspecific interaction affected belowground C allocation (including root biomass, root respiration and rhizodeposition) and N acquisition through soil N uptake and biological N fixation. Results: Drought increased belowground C allocation per unit of N acquisition in the legume, but not in the grass. Drought significantly reduced biological N fixation in the legume, so that the legume allocated relatively more C to take up soil N. Interspecific competition increased belowground C allocation per unit of N acquisition, which could be attributed to a reduction in biological N fixation by the legume and an increased abundance of the grass. Conclusions: We highlight that drought and interspecific competition for N strongly alter C allocation towards biological N fixation and soil N uptake. Our measurements provide important process-based information to improve modeling drought effects on productivity and composition in legume-grass mixtures. [ABSTRACT FROM AUTHOR]

Purpose : Nitrogen (N) transfer from white clover (Trifolium repens cv.) to ryegrass (Lolium perenne cv.) has the potential to meet ryegrass N requirements. This study aimed to quantify N transfer in a mixed pasture and investigate the influence of the microbial community and land management on N transfer. Methods: Split root 15N-labelling of clover quantified N transfer to ryegrass via exudation, microbial assimilation, decomposition, defoliation and soil biota. Incorporation into the microbial protein pool was determined using compound-specific 15N-stable isotope probing approaches. Results: N transfer to ryegrass and soil microbial protein in the model system was relatively small, with one-third arising from root exudation. N transfer to ryegrass increased with no microbial competition but soil microbes also increased N transfer via shoot decomposition. Addition of mycorrhizal fungi did not alter N transfer, due to the source-sink nature of this pathway, whilst weevil grazing on roots decreased microbial N transfer. N transfer was bidirectional, and comparable on a short-term scale. Conclusions: N transfer was low in a model young pasture established from soil from a permanent grassland with long-term N fertilisation. Root exudation and decomposition were major N transfer pathways. N transfer was influenced by soil biota (weevils, mycorrhizae) and land management (e.g. grazing). Previous land management and the role of the microbial community in N transfer must be considered when determining the potential for N transfer to ryegrass. [ABSTRACT FROM AUTHOR]

The current study investigated the influence of mixture composition on the biomass yield and early establishment of legume–grass mixtures. The legume species alfalfa (Medicago sativa L. (A)), white clover (Trifolium repens L. (WC)), and red clover (Trifolium pratense L. (RC)) and grass species orchardgrass (Dactylis glomerata L. (O)), tall fescue (Festuca arundinacea Schreb. (TF)), and perennial ryegrass (Lolium perenne L. (PR)) were grown in monocultures and in different legume–grass mixtures. Legume–grass mixtures (M1: WC + O + TF; M2: A + O + TF; M3: A + WC + O + TF; M4: RC + WC + O + TF; M5: A + WC + O + TF + PR; M6: RC + WC + O + TF + PR; and M7: A + RC + WC + O + TF + PR) were sown in a legume–grass seeding ratio of 3:7. The results showed that M2 had the greatest two-year average biomass yield (12.92 t ha−1), which was significantly (p < 0.05), 4.7%, 5.4%, 15.8%, and 29.1% greater than that of WC monoculture, M7, M4, and M1, respectively. The grass biomass yield proportions of all mixtures significantly decreased, while legume biomass yield proportions significantly increased in the second year compared to the first year of establishment. The land-equivalent ratio values of M2 and M4 were greater than 1 in each cutting period. The competition rate of grasses gradually decreased with prolonged establishment time. Overall, the biomass yield, legume and grass biomass yield proportions, land equivalent ratio, and competition rate data highlighted that M2 is the best choice to achieve greater productivity and early establishment in southwest China. [ABSTRACT FROM AUTHOR]

The aim of the research was to determine the factors defining the growth and development of Lolium perenne and Trifolium repens upon petroleum contamination. The top layer of clay soil contaminated with petroleum products resulting from an oil pipeline failure was collected for the tests. The control was the same type of uncontaminated soil with the addition of, under laboratory conditions, tissue paper. The research was conducted in two stages. The first concerned the germination process and seedlings parameters (Petri dishes). The germination energy (GE) and the germination capacity (GC) of seeds were determined. The seedling's development was also evaluated based on 'WinRhizo PRO 2009' software. Then, in the second stage, pot tests were carried out, where the growth and development of species in the first year after sowing were temporarily measured. The parameters studied were the number, height, green and dry masses of the plants. A Gompertz regression model describing seed species germination and number species as time dependent dynamic was applied. The data were analysed statistically using variance analysis (ANOVA) and the PCA (principal component analysis) method. The results of our study indicated that admixture of petroleum into the soil does not seriously affect the development dynamics of Lolium perenne seedlings. The diesel oil contamination mostly affects the germination of the Trifolium repens by a statistically significant increase of the maximum value of germination and increasing the maximum growth rate. [ABSTRACT FROM AUTHOR]

The purpose of the experiment is to determine the composition and energy value of fodder from monoculture and mixed grass stands of perennial ryegrass with legume fodder crops under mountain conditions. It was found that the concentration of the fiber components of the cell walls in the monoculture grass stands of perennial ryegrass was significantly higher compared to the mixed ones, which affected the forage mass digestibility. The highest dry matter digestibility was registered in the biomass of Lolium perenne L. + Trifolium repens L. mixture (642.54 g kg-1 DM) followed by Lolium perenne L. + Lotus corniculatus L. (636.28 g kg-1 DM) and Lolium perenne L. + Trifolium pratense L. (622.18 g kg-1 DM). The monoculture grass stands with red clover had the highest content of neutral detergent fibers (418.03 g kg-1 DM), whereas the bird's-foot-trefoil biomass had the highest concentration of acid detergent fibers (291.98 g kg-1 DM), acid-detergent lignin (70.72 g kg-1 DM) and cellulose (221.27 g kg-1 DM). The forage mass of pasture ryegrass registered lower values for all the investigated parameters compared to its mixtures with leguminous forage crops. The highest caloric content is the harvested grass stands of Lolium perenne L. with Lotus corniculatus L. (17.48 MJ/kg DM). Biomass also has the highest average value of energy useful for the normal course of physiological needs in the animal organism (7.45 MJ/kg DM), as well as in terms of the number of feed units for milk (0.68 in kg DM) and growth (0.62 in kg DM). [ABSTRACT FROM AUTHOR]

Photosynthetically derived carbon (C) is allocated belowground, allowing plants to obtain nutrients. However, less is known about the amount of nutrients acquired relative to the C allocated belowground, which is referred to as C efficiency for nutrient acquisition (CENA). Here, we examined how C efficiency for nitrogen (N) and phosphorus (P) acquisition varied between ryegrass (Lolium perenne) and clover (Trifolium repens) with and without P fertilization. A continuous 13C-labeling method was applied to track belowground C allocation. Both species allocated nearly half of belowground C to rhizosphere respiration (49%), followed by root biomass (37%), and rhizodeposition (14%). With regard to N and P, CENA was higher for clover than for ryegrass, which remained higher after accounting for relatively low C costs associated with biological N2 fixation. Phosphorus fertilization increased the C efficiency for P acquisition but decreased the C efficiency for N acquisition. A higher CENA for N and P in clover may be attributed to the greater rhizosphere priming on soil organic matter decomposition. Increased P availability with P fertilization could induce lower C allocation for P uptake but exacerbate soil N limitation, thereby making N uptake less C efficient. Overall, our study revealed that species-specific belowground C allocation and nutrient uptake efficiency depend on which nutrient is limited. [ABSTRACT FROM AUTHOR]

Carbon (C) cycling is crucial to agroecosystem functioning. Important determinants for the belowground C flow are soil food webs, with microorganisms and microfaunal grazers, i.e., nematodes, as key biota. The present study investigates the incorporation of plant-derived C into the nematode micro-food web under two different cropping systems, grassland (ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.)) and agroforest (willow (Salix schwerinii Wolf and Salix viminalis L)). To quantify the C flux from the plant into the soil micro-food web, grass and willow were pulse-labeled with 13CO2 and the incorporation of 13C into the nematode trophic groups was monitored 3, 7, 14 and 28 days after labeling. The natural stable isotope signals (13C/12C, 15N/14N) were analyzed to determine the structure of the nematode micro-food web. The natural isotopic δ15N signal revealed different trophic levels for omnivores and predators in grassland and agroforest soils. The incorporation of plant C into nematode tissue was detectable three days after 13CO2 labeling with the highest and fastest C allocation in plant feeders in grassland, and in fungal feeders in agroforest soil. C flux dynamics between the aboveground vegetation and belowground micro-food web varied with cropping system. This demonstrates that crop-specific translocation of C affects the multitrophic interactions in the root environment, which in turn can alter soil nutrient cycling. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine fluctuations in white clover (Trifolium repens L.) content in perennial ryegrass (Lolium perenne L.) swards within a high nitrogen (250 kg N/ha) input grazing dairy system. The data came from a larger, overall system experiment within which all management and growing condition variables were categorised each year for the 40 paddocks that contained perennial ryegrass-white clover swards, over four growing years. Within that study, eight perennial ryegrass cultivars were examined, each sown individually with two white clover cultivars in a 50:50 mix of 'Chieftain' and 'Crusader'. To determine management associations and meteorological patterns with white clover content and rate/direction of change, separate generalised linear models were used to analyse each individual management or meteorological variable. Paddocks with high white clover contents were associated with lower pre- and post-grazing sward heights, lower pasture cover over the winter period and shorter over-winter period. Perennial ryegrass cultivars with lower pre- and post-grazing height, lower pre-grazing pasture mass and pasture yield removed, all retained more white clover in their swards. Soil fertility remained a key factor that affected white clover persistence influencing the degree of responses in all treatments, particularly soil phosphorus (P) levels. Beyond this, higher white clover contents and lower rates of white clover decline were associated with paddocks that received lower rainfall, had higher soil moisture deficits and received more radiation into the base of the sward, particularly around the time of grazing. [ABSTRACT FROM AUTHOR]

Understanding the determinants of early invasion resistance is a major challenge for designing plant communities that efficiently repel invaders. Recent evidence highlighted the significant role of priority effects in early community assembly as they affect species composition, structure and functional properties, but the consequences of native community assembly history on the success of subsequent invasions has not been elucidated yet. In a greenhouse experiment, we investigated how (1) the identity of the first native colonizing species (one of two grasses: Dactylis glomerata and Lolium perenne , or two legumes: Onobrychis viciifolia and Trifolium repens), each introduced four weeks before the rest of the native community, and (2) timing of species establishment (synchronous vs. sequential sowing), influenced early establishment success of Ambrosia artemisiifolia , an annual noxious weed in Europe. First colonizer identity and establishment timing both affected early biomass production and composition of the community, and had implications for A. artemisiifolia early invasion success. Invasion success decreased when all native individuals were sown simultaneously, quickly generating a high biomass production, while it increased when the productive N-fixing legume T. repens was sown first. These findings support that native species assembly history matters to invasion resistance in the early growth stages, thus opening the way to more effective invasive species management strategies in restoration. [ABSTRACT FROM AUTHOR]

Background: The nitrogen (N) response in grass-clover is influenced by quantity and timing of N-fertilizer, but less is known about the effect of fertilizer type (animal manure vs. mineral N) and N form (ammonium vs. nitrate). Method: A field trial was established in a mixture of white clover (Trifolium repens L.), red clover (Trifolium pratense L.) and perennial ryegrass (Lolium. perenne L.) with mineral N and slurry. DM yield in grass and clover and N2-fixation activity (%Ndfa) was determined in four cuts during the season. Results: Fertilization resulted in a peak in soil mineral N within 1-2 weeks of application and decreased to background rate prior to plant harvest. No differences in white clover N2-fixation activity were found between fertilizer types within each N level. Conclusions: The experiment showed that mineral N form does not affect the regulation of N2-fixation activity. The fertilizer N level was the only factor affecting white clover N2-fixation activity. Further, the results demonstrated an N threshold below which annual %Ndfa was always high (~90%). This was controlled by the companion grass' ability to deplete the soil mineral N pool. When N fertilization exceeded this threshold (above 180 kg N ha-1 yr-1 in our case) annual %Ndfa significantly decreased as did qBNF in the harvested biomass. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of cow genotype and parity on dry matter intake (DMI) and production efficiencies in pasture-based systems. Three dairy cow genotypes were evaluated over 3 yr; 40 Holstein-Friesian (HF), 40 Jersey × HF (JEX), and 40 Norwegian Red × JEX (3WAY) each year, with each genotype grazed in equal numbers on 1 of 4 grazing treatments in a 2 × 2 factorial arrangement of treatments [diploid or tetraploid perennial ryegrass (Lolium perenne L.) with or without white clover (Trifolium repens L.)]. A total of 208 individual cows were used during the experiment. The effect of parity (lactation 1, 2, and 3+) was also evaluated. Individual DMI was estimated 8 times during the study, 3 times in 2015 and in 2017, and twice in 2016, using the n-alkane technique. Days in milk at each DMI measurement period were 64, 110, and 189, corresponding to spring, summer, and autumn. Measures of milk production efficiency calculated were total DMI/100 kg of body weight (BW), milk solids (kg fat + protein; MSo)/100 kg of BW, solids-corrected milk (SCM)/100 kg of BW, and unité fourragère lait (net energy requirements for lactation equivalent of 1 kg of standard air-dry barley; UFL) available for standard (4.0% fat and 3.1% protein content) milk production after accounting for maintenance. During the DMI measurement periods HF had a greater milk yield (23.2 kg/cow per d) compared with JEX and 3WAY (22.0 and 21.9 kg/cow per d, respectively) but there was no difference in MSo yield. Holstein-Friesian and JEX, and JEX and 3WAY had similar DMI, but HF had greater total DMI than 3WAY (DMI was 17.2, 17.0, and 16.7 kg/cow per d for HF, JEX, and 3WAY, respectively). Jersey × Holstein-Friesian cows were the most efficient for total DMI/100 kg of BW, SCM/100 kg of BW, and MSo/100 kg of BW (3.63, 4.96, and 0.39 kg/kg of BW) compared with HF (3.36, 4.51, and 0.35 kg/kg of BW) and 3WAY (3.45, 4.63, and 0.37 kg/kg of BW), respectively. Unité fourragère lait available for standard milk production after accounting for maintenance was not different among genotypes. As expected, DMI differed significantly among parities with greater parity cows having higher DMI and subsequently higher milk and MSo yield. Although all 3 genotypes achieved high levels of DMI and production efficiency, JEX achieved the highest production efficiency. Some of the efficiency gains (SCM/100 kg of BW, MSo/100 kg of BW, and total DMI/100 kg of BW) achieved with JEX decreased when the third breed (Norwegian Red) was introduced. [ABSTRACT FROM AUTHOR]

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The effect of soil environment on cultivars compatibility was evaluated in a cutting field experiment during two growing seasons. A factorial combination of four perennial ryegrass (Lolium perenne L.; PR) and three white clover (Trifolium repens L.; WC) cultivars were grown on deep (DSS) and shallow (SSS) soils under irrigated conditions. Measurements included herbage accumulation (HA), root attributes, leaf chlorophyll content, and interception of photosynthetic radiation. The PR–WC compatibility was affected by soil environment. In both soil sites and growing seasons, the WC + PR herbage accumulations were similar but with different PR and WC partial accumulation. In DSS, the partial PR HA was 22% less than that observed in SSS; the partial WC HA was almost twice in DSS relative to SSS. In SSS, the WC stolon growing point numbers, stolon length, and stolon biomass increased 60, 88, and 94% relative to DSS, respectively. In the same way, the mixed sward increased root biomass and root length density, which was considered as a mechanism for improving plant resources capture from the soil. At cultivar level, the PR–WC compatibility was affected mainly by WC cultivar, and the effect of PR cultivar was fairly weak. The medium‐leaved WC cultivar 'Will' showed the greatest compatibility with PR, particularly with cultivar 'Bealey'. These results are valuable when designing new management strategies for mixed sward production in marginal environments. Modern cultivars of PR have capacity for adapting to marginal environments; however, it is necessary to improve the competitive ability of WC to capture soil resources under marginal soil conditions. Core Ideas: Understanding compatibility of perennial ryegrass and white clover cultivars allows for optimized mixed sward herbage accumulation.Modern cultivars of perennial ryegrass have capacity for adapting to marginal environments.Mixed sward changes its phenotypic expression in marginal environments. [ABSTRACT FROM AUTHOR]

The nutrient use efficiency of perennial ryegrass (Lolium perenne L.) (PR) and white clover (Trifolium repens L.) (WC) cultivars can affect the grass-legume compatibility of different cultivar combinations, thus impacting the sustainability of animal production systems, especially on marginal soils. The objective of this work was to evaluate N, P, and K absorption efficiency (NAE, PAE, and KAE) and use efficiency (NUE, PUE, and KUE). This study included two experiments with the same full factorial treatment structure (4 PR cultivars x 3 WC cultivars) in a randomized complete block design under field conditions and a completely randomized pot design. The field cutting experiment was carried out on sites with two contrasting soil depths and the pot experiment was conducted under shade conditions. Results showed nonsignificant (P > 0.05) factor interactions for DM yield and both nutrient absorption and use efficiency. The NAE and PAE of PR 'Extreme' and 'Bealey' were higher under field conditions than pot conditions. In the field experiment, NAE of WC 'Will' (2.33 kg DM ha-1)/mg N kg-1)) tended to be similar (P < 0.05) to other cultivars in deep soil, but was significantly higher (P < 0.001) than 'Ladino' and 'Bounty' in shallow soil (0.70 kg DM ha-1)/mg kg-1). The evaluation of NUE and PUE under field conditions and KUE under pot conditions showed that PR 'Bealey' and WC 'Ladino' reached higher values. In conclusion, results showed a cultivar effect on nutrient use efficiency in PR/WC mixtures, which had an impact on PRWC compatibility, mainly due to the higher absorption efficiency of PR 'Bealey' and WC 'Will', both of which exhibited the highest degree of compatibility for total DM yield. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is cultivated in many countries for its high yield and good quality forage. Its cultivars have specific functional traits, such as phenology, growth habit and rate, which affect the competitiveness and productivity of mixtures. The cultivation of new cultivars of perennial ryegrass or mixtures of cultivars in swards is one of the complementary measures to improve the condition of swards. The study was aimed to determine the productivity potential of three newer, less investigated Lithuanian perennial ryegrass (Lolium perenne L.) cultivars 'Elena DS', 'Raminta', 'Verseka', and cultivar mixtures in single-species swards and in mixtures with legumes - white and red clover. The experiment was set up in the central part of Lithuania in the Nemoral climate zone. Mineral fertilisers were not used for the mixtures with legumes, singlespecies crops were fertilised with N150 kg ha-1 yr-1. Over the two experimental years, the average dry matter yield of perennial ryegrass was 8.00 t ha-1 for the 'Elena DS', 7.4 t ha-1 for 'Verseka', 6.9 t ha-1 for 'Raminta' and 7.4 t ha-1 for the cultivar mixture. In the 1st year of sward use, the productivity of the perennial ryegrass cultivars did not differ significantly. In the 2nd year, the productivity of 'Elena DS' was significantly higher compared with that of the other cultivars cultivated in single-species crops. The influence of functional traits of the cultivars was significant in the first year of cultivation and persisted in single-species swards but not in mixtures from the second year onwards. The plants of the cultivar 'Elena DS' allowed the development of clover in the mixture, resulting in an increase in herbage productivity and crude protein content. The results of the experiment suggest that a mixture of perennial ryegrass cultivars can be used in swards, as a similar dry matter yield was recorded compared to a single-cultivar swards. However, the benefits of swards may vary from season to season, and more research is needed to assess the impact of a mixture of cultivars on grass productivity and quality with ageing of swards and accumulation in different environmental conditions. [ABSTRACT FROM AUTHOR]

Background and Aims The drivers of white clover (Trifolium repens) architecture and productivity are still imperfectly understood. Our aim here was to investigate the impact of genetic background, neighbourhood and season on different architectural traits, clover and total biomass yield, as well as the relationship between those traits and yield. Methods We grew eight white clover populations in pure stands and in mixed stands with contrasting mixture partners. Over four consecutive regrowth periods within 1 year, we measured trait sizes and determined clover and total yield amounts. Key Results The size of the architectural traits differed between populations and changed in response to neighbourhood and season. Population did not affect the sign or degree of those changes. Among the tested factors, season was by far the most important driver of white clover architecture, with the seasonal pattern notably differing between architectural traits. Clover and total yield were positively related to the architectural traits leaf area, petiole length, internode length and specific leaf area. Whereas the direction of the relationship was widely unaffected, its magnitude was clearly altered by neighbourhood and season. Conclusions Our results show that seasonal effects are the key for a deeper understanding of the architecture of white clover individuals and to improve the productivity of white clover communities. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of perennial ryegrass (Lolium perenne L.; PRG) ploidy and white clover (Trifolium repens L.) inclusion on milk production, dry matter intake (DMI), and milk production efficiencies. Four separate grazing treatments were evaluated: tetraploid PRG only, diploid PRG only, tetraploid PRG with white clover, and diploid PRG with white clover. Individual DMI was estimated 8 times during the study (3 times in 2015, 2 times in 2016, and 3 times in 2017) using the n -alkane technique. Cows were, on average, 64, 110, and 189 d in milk during the DMI measurement period, corresponding to spring, summer, and autumn, respectively. Measures of milk production efficiency were total DMI/100 kg of body weight (BW), milk solids (kg of fat + protein; MSo)/100 kg of BW, solids-corrected milk/100 kg of BW, and MSo/kg of total DMI. Perennial ryegrass ploidy had no effect on DMI; however, a significant increase in DMI (+0.5 kg/cow per day) was observed from cows grazing PRG-white clover swards compared with PRG-only swards. Sward white clover content influenced DMI as there was no increase in DMI in spring (9% sward white cover content), whereas DMI was greater in summer and autumn for cows grazing PRG-white clover swards (+0.8 kg/cow per day) compared with PRG-only swards (14 and 23% sward white clover content, respectively). The greater DMI of cows grazing PRG-white clover swards led to increased milk (+1.3 kg/cow per day) and MSo (+0.10 kg/cow per day) yields. Cows grazing PRG-white clover swards were also more efficient for total DMI/100 kg of BW, solids-corrected milk/100 kg of BW, and MSo/100 kg of BW compared with cows grazing PRG-only swards due to their similar BW but higher milk and MSo yields. The results highlight the potential of PRG-white clover swards to increase DMI at grazing and to improve milk production efficiency in pasture-based systems. [ABSTRACT FROM AUTHOR]

White clover (Trifolium repens L.) is at a disadvantage to perennial ryegrass (Lolium perenne L.; PRG) due to its limited cold tolerance and low growth rates at colder temperatures, which can affect subsequent spring herbage dry matter (DM) availability. The effect of PRG ploidy on white clover morphology and growth over winter, and its subsequent recovery in spring and the following growing season, is poorly understood. The objective of this study was to compare the effect of white clover inclusion and PRG ploidy on sward structure, plant morphology and growth of PRG--white clover swards over winter. Four swards (diploid PRG only, tetraploid PRG only, diploid PRG--white clover and tetraploid PRG--white clover) were evaluated over a full winter period (November-February) at a farmlet scale. The PRG ploidy had no effect on herbage DM production, white clover content or tissue turnover (P > 0.05) over winter. However, white clover inclusion caused a significant decrease in herbage DM production (P < 0.001; -254 kg DM/ha) and tiller density (P < 0.001; -1,953 tillers/m2) over winter. Stolon mass was not affected by PRG ploidy (P > 0.05); however, stolon length and number of leaves per stolon were affected by PRG ploidy (P < 0.05). Including white clover in PRG swards can alter winter sward dynamics, potentially causing difficulties in subsequent spring management and performance due to the reduced over-winter growth rate when compared with PRG. [ABSTRACT FROM AUTHOR]

The aim of the paper is to highlight the role of natural germoplasm resource of the species Lolium perenne by adapting it to a wide variety of abiotic conditions. The impact of the presence of the species together with other legume species such as Trifolium repens in the construction of multifunctional temperate climate associations is also studied. The concept of meadow multifunctionality has developed with the reconsideration of their sustainability character in terms of an emphasis on the negative impact on the environment. Land use change in recent decades, the abandonment of grazing and the decline of traditional agricultural practices or afforestation are a major threat to biodiversity. Often the bispecific dominance between Lolium perenne and Trifolium repens is improve both feed quality and soil quality due to the added value of fixing atmospheric nitrogen. The species of Lolium perenne due to its high ecological plasticity is thus considered to be particularly important especially due to the fact that it covers a wide range of environmental conditions thus developing models of great genetic diversity which leads to a development of genomic resources. Lolium perenne is thus adapted to defoliation, fertilization and growth cycles, which is particularly important because defoliation through animal grazing can have major effects on the structure and functioning of grassland ecosystems affecting the production of shoots and root rotation of communities. of plants, but also photosynthetic rates and carbon allocation in plants: energy flow in the plant-soil system. Thus, the highlighting of the qualities of Lolium perenne species are important premises for the genetic progress of this species but especially for understanding the natural functioning of plant associations dominated by it, which leads to environmentally friendly management practices. [ABSTRACT FROM AUTHOR]

The sustainability of small-scale dairy systems in the highlands of Central Mexico is limited by the economic scale due to a high dependence of external inputs, particularly commercial concentrates, as well as the use of low-quality straws that result in high feeding costs which result in low profitability. Grazing of irrigated cultivated pastures based on temperate grasses reduces feeding costs, improves profitability and hence the sustainability of these systems. However, pasture species must be assessed for their adaptation to the agroecological and management conditions of small-scale dairy farms. Therefore, the objective was to evaluate bromegrass (Bromus catharticus Vahl cv Matua) as a pasture resource in comparison with two varieties of perennial ryegrass (Lolium perenne L cv Bargala and cv Payday) and Festulolium (cv Spring Green), in two participatory on-farm experiments in spring and autumn. The first experiment (EXP 1) compared Matua bromegrass (MBRG) with Bargala perennial ryegrass (BPRG), on their own or as a 50:50 mixture of the two grasses. The second experiment (EXP 2) compared Matua bromegrass (MBRG) with Pay Day perennial ryegrass (PDRG) and Festulolium cv Spring green (SGFL). All pastures in both experiments were associated with white clover (Trifolium repens cv Ladino). There were no statistically significant differences found in EXP 1 (P>0.05) for animal production variables with a mean milk yield of 19.41±0.14 kg/cow/day. On the other hand the second experiment showed significant differences (P<0.05) in milk yield for Matua bromegrass (16.7 kg cow/day), 9% less tan for Pay Day perennial ryegrass and Spring Green festulolium. It was concluded that Matua bromegrass showed similar performance to Bargala perennial ryegrass in spring but less than Pay Day perennial ryegrass and Spring Green festulolium in autumn. It is necessary to further investigate if differences were due to a season effect in order to fully establish the value and role of bromegrass as a viable pasture grass species for irrigated pastures in small-scale dairy systems. [ABSTRACT FROM AUTHOR]

In urban landscaping, lawns are one of the main components of landscape compositions. They have important functions - biological, ecological, aesthetic, architectural, etc. The publication presents a literature analysis of seven species of grasses - Poa pratensis, Festuca rubra, Lolium perenne, Аgrostis tenius, Arrhenatherum elatius, Cynodon dactylon, and Trifolium repens, which are basic in creating lawns. Their botanical characteristics and ecological requirements, their resistance to trampling and their decorative qualities have been assessed. For the creation of quality grass carpets is important and good agricultural techniques, including - tillage, fertilizing, watering, sowing, mowing, aeration and cleaning and weed protection, which is the subject of analysis in the article. [ABSTRACT FROM AUTHOR]

To compare lead (Pb) tolerance and accumulation characteristics, 14 herbaceous plants were treated with different concentrations of lead (0 mg·kg-1, 500 mg·kg-1, 1000 mg·kg-1, 1500 mg·kg-1, 2000 mg·kg-1) through an indoor pot experiment. Results indicated that the shoot dry weights (DWs), tolerance index (TI) and root tolerance index (RTI) of 14 herbaceous plants decreased with the increase of lead concentration. After comprehensive evaluation, Campsis grandiflora, Polygonum lapathifolium, Lolium perenne, and Poa annua were confirmed as tolerant plants to be cultivated in lead-zinc mining area. Moreover, shoots of the Rudbeckia hirta could effectively absorb the lead (I I) with the bioconcentration factor (BCF) of 2.29. The translocation factor (TF) of 6 herbaceous plants were larger than 1.0. They are: Polygonum lapathifolium (3.04) > Medicago sativa (2.49) > Rudbeckia hirta (1.72) > Talinum paniculatum (1.44) > Capsicum annuum cv. 276 (1.36) > Trifolium repens (1.21. Finally, after integration the BCF, TF and repair potential indices, we found that Rudbeckia hirta had a good restoration potential and its lead cumulation in the shoot was the highest (2.576 mg per plant) when the concentration was up to 1000 mg·kg-1. Therefore, Rudbeckia hirta could be identified as a pioneer species of Pbhyperaccumulator. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of dolomite amendment on the forage yield in the rainy and dry season in Nariño, Colombia. Materials and Methods: A trial was conducted at the Obonuco research center (AGROSAVIA). A split-plot design in complete randomized blocks was developed, with 18 treatments and three repetitions, for a total of 54 experimental units. The green forage, dry matter and pH, were evaluated. Variance analysis was carried out and Tukey's test was applied to establish significant differences (p = 0,05). The obtained information was analyzed through the program R V.3.6.1. Results: In the rainy season significant differences (p < 0,001) were found for the green forage and dry matter yield, in favor of the association of Dactylis glomerata L. + Trifolium repens L. + Trifolium pratense L., with values of 1 817 and 2 922 kg ha-1, respectively. In the dry season, differences (P < 0,05) were found for the green forage and dry matter yields. The mixture of Lolium perenne L + T. repens showed values of 13 312,2 kg ha-1 and 2501,3 kg ha-1 respectively. In the evaluated period no differences were observed for pH among the treatments. Conclusions: For the rainy and dry seasons, the associations of D. glomerata + T. repens + T. pratense and L. perenne + T. repens favored the yields at the harvest age of 35 days. [ABSTRACT FROM AUTHOR]

In New Zealand, a commonly sown pasture combination is perennial ryegrass with white clover. The hydrothermal time model (HTT) was used to quantify germination under different temperature (T) and water potential (WP) conditions for white clover 'Nomad' and perennial ryegrass 'Stellar AR1'. Seeds were germinated in vitro under a range of T × WP combinations, and HTT models were fitted to germination time course data. Rapid germination of white clover under optimum T and WP was reflected by a much lower value for its HTT constant compared with perennial ryegrass (10.8 vs 80.7 MPa °C d). However, the lower base water potential for perennial ryegrass (−1.29 vs −0.495 MPa) and a higher threshold temperature for thermoinhibition (21.8 vs 18.3°C), meant that predicted perennial ryegrass germination was more resilient in warm dry conditions. HTT models can be used to assist decisions about the timing of perennial ryegrass and white clover sowing. [ABSTRACT FROM AUTHOR]

In mountain regions, the likelihood of mudflows might increase due to climate change. Although mudflows are common worldwide and devastate agricultural land, virtually nothing is known about the revegetation of mudflow deposits for agricultural purposes. To provide recommendations for rapid revegetation of mountain pastures, 52 permanent plots (4 m × 4 m) on 20 revegetated mudflow deposits in the Nature Park Sölktäler were established. We evaluated different revegetation measures (seed addition alone or combined with application of straw, lime or cattle manure) two years after sowing using commercial clover-grass seed mixtures. Furthermore, 27 permanent plots on 15 unsown mudflow deposits were surveyed. Sowing seeds can considerably accelerate revegetation on siliceous mudflow deposits. Festuca rubra, Agrostis capillaris, Lolium perenne, Trifolium repens and Lotus corniculatus are particularly suitable for rapid grassland reestablishment, whereas Poa pratensis is not recommendable. A pure straw application should be avoided because it delays the revegetation success. Lime addition is not recommended because it can lead to an undesirable legume dominance if clover-grass seed mixtures are used for revegetation. The most effective measure for large-scale revegetation seems to be seed addition without additives. To facilitate revegetation on coarse-grained deposits, large rocks should be crushed using a stone mill. [ABSTRACT FROM AUTHOR]

The increasing frequency of extreme weather events, such as floods, requires management strategies that promote resilience of grassland productivity. Mixtures of plant species may better resist and recover from flooding than monocultures, as they could combine species with stress‐coping and resource acquisition traits. This has not yet been tested in intensively managed grasslands despite its relevance for enhancing agroecosystem resilience.Using intact soil cores from an 18‐month‐old field experiment, we tested how 11 plant communities (Festuca arundinacea, Lolium perenne, Poa trivialis and Trifolium repens in monoculture, two‐ and four‐species mixtures) resist and recover from repeated flooding in a 4‐month greenhouse experiment.We found that plant community composition, not whether the community was a mixture or monoculture, influenced the community's resistance to flooding, although most communities were able to resist and recover from both floods.The plant community's position on the leaf economic spectrum in flooded conditions was related to its resistance to and recovery from flooding. Resistance to and recovery from a severe flood were related to flood‐induced intraspecific trait variation, causing a shift in the community's position on the leaf resource economic spectrum. In flooded conditions, resource‐conservative communities (characterized by low specific leaf area, low leaf nitrogen content and high leaf dry matter content) better resisted and recovered from flooding. The community's position on the root resource economic spectrum was less connected to the community's resistance and recovery.Synthesis and applications. Our study shows that in flooded conditions, resource‐conservative plant communities are more resilient to flooding than resource‐acquisitive communities in an intensively managed grassland. This suggests that plant community position on the leaf economic spectrum, as well as species' flood‐induced intraspecific variation, should be considered when designing grasslands to withstand increasing flood frequency and severity. [ABSTRACT FROM AUTHOR]

As the dynamics and magnitude of rhizodeposition vary considerably among cropping systems, we investigated effects of cropping system on the incorporation of root-derived carbon (C) into Collembola, a dominant taxon of soil microarthropods. In the field, we used 13CO2 to pulse label a crop monoculture (oilseed rape, Brassica napus L.), a mixed-grass community (dominated by Lolium perenne L. mixed with clover Trifolium repens L.), and a tree plantation (willow, Salix schwerinii E.L. Wolf and Salix viminalis L.). During 28 days, the incorporation of 13C was traced in nine species of Collembola including epedaphic (surface-dwelling), hemiedaphic (litter-dwelling), and euedaphic (soil-dwelling) functional groups. Incorporation of 13C into Collembola reached a plateau before day 3 after the labeling in grass and willow, but increased up to day 14 in rape. While euedaphic Collembola incorporated less root-derived C than epedaphic and hemiedaphic Collembola in rape and willow, the incorporation of 13C was similar among functional groups in grass. Differential incorporation of 13C in euedaphic species points to niche differentiation within the same functional group. Our findings highlight that cropping system not only affects the flux of root C into soil mesofauna, being slower in rape than in grass and willow, but also the utilization of root-derived resources by functional groups and species of Collembola. The results indicate that pronounced differences in belowground C inputs between cropping systems affect microbivores as basal species and thereby soil food webs and their functioning and services. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the economic performance of 2 sward types [perennial ryegrass (PRG; Lolium perenne L.) sown with or without white clover (Trifolium repens L.)] grazed by 3 cow genotypes. Physical performance data were collected from a 4-yr systems experiment based at Clonakilty Agricultural College, Clonakilty, Co. Cork, Ireland. The experiment compared 2 sward types (PRG-only swards and PRG–white clover swards), with each sward type being grazed by cows from 3 genotypes [Holstein-Friesian (HF), Jersey × HF (JEX), and Norwegian Red × JEX (3-way)]. All systems were stocked at 2.75 cows/ha with fixed fertilizer applications and concentrate supplementation. The data supplied 6 production systems (2 sward types × 3 cow genotypes). The production systems were modeled using the Moorepark Dairy Systems Model (stochastic budgetary simulation model) under 2 scenarios, one in which land area was fixed and one in which cow numbers were fixed. The analysis was completed across a range of milk prices, calf prices, and reseeding programs. The analysis showed that in the fixed-land scenario with a milk price of €0.29/L, adding white clover to PRG swards increased profitability by €305/ha. In the same fixed-land scenario, JEX cows were most profitable (€2,606/ha), followed by 3-way (€2,492/ha) and HF (€2,468/ha) cows. In the fixed-cow scenario, net profit per cow was €128 greater for PRG–white clover swards compared with PRG-only swards. In this scenario, JEX was the most profitable per cow (€877), followed by HF (€855) and 3-way (€831). The system that produced the highest net profit was JEX cows grazing PRG–white clover swards (€2,751/ha). Regardless of reseeding frequency or variations in calf value, JEX cows grazing PRG–white clover swards consistently produced the highest net profit per hectare. [ABSTRACT FROM AUTHOR]

The objective of this research was to compare yearling beef calf production (bodyweight – BW gains and carcass characteristics) under organic and conventional (semi-extensive) management. The study comprised three production cycles (from weaning to slaughter) with a total of 67 calves. For the grazing periods, three replicates (1.6-ha paddocks with Lolium perenne – Trifolium repens pasture) per treatment were established, and 4–5 animals per paddock were managed. Conventional paddocks were fertilised with synthetic NPK, whereas manure was used in the organic ones. During finishing, conventional feeding consisted of concentrate ad libitum with straw (CC). Under organic regulation, pasture grazing (PG), herbage silage (HS) and maize silage (MS), all supplemented with organic concentrate, were tested. Results showed similar individual performances before finishing in both treatments. Daily BW gain per unit area during spring was greater in conventional than in organic system (5.62 vs 4.27 kg/ha; P < 0.01), propitiating greater final production in the former, a result of greater herbage production allowing higher stocking rates managed on conventional pastures. During finishing, CC yearlings had greater (P < 0.001) BW gains (1340 g/day) compared with organic feeding systems, although MS feeding enhanced the gains (1116 g/day) over those achieved in PG or HS (average 709 g/day). There were no differences among feeding systems in carcass weight and conformation, while the rib dissection revealed greater fat contents in CC and MS relative to PG and HS (10.2 vs 7.5%; P < 0.05). Feeding with maize silage during finishing could be a good option to achieve organic beef production levels close to the conventional ones. However, the high price of organic concentrate raised feeding costs during finishing in a way that organic beef fattening was 36% less efficient than the conventional system in terms of product sales (applying the same price per kg carcass weight) minus feeding costs per unit of land area. Organic beef production is increasing in interest among farmers and consumers worldwide, but it might present limitations compared with conventional fattening of calves. Comparing both systems, we found greater production per unit area in conventionally fertilised pastures than in organically managed ones (applying only manure) because 27% less animals could be managed in the latter. Under organic regulations, feeding yearlings with maize silage plus concentrate before slaughter provided acceptable gains and carcass traits, close to conventional feeding with concentrates. [ABSTRACT FROM AUTHOR]

To screen out plants with hyperaccumulation of heavy metals and explore the effects of root exudates on the phytoremediation in contaminated soils. The germination rates of five plants including Lolium perenne L. (L. perenne), Sorghum sudanense (Piper) Stapf. (S. sudanense), Pennisetum alopecuroides (L.) Spreng. (P. alopecuroides), Medicago sativa L. (M. sativa), and Trifolium repens L. (T. repens) in different concentrations of cadmium ion solution (0–100 mg/kg) were determined. The growth adaptability of these five plants under conditions of contaminated soils with the above cadmium ion concentrations was also evaluated. S. sudanense and P. alopecuroides had higher germination rates and better growth than the three other plants and were selected as the latter experimental varieties. The activation amounts of cadmium ion in soils were measured using AAS in the presence of three types of root secretions (citric acid, glycine, and maltose) with different concentrations (10–500 mmol/L). The activation amounts decrease in the following order: citric acid > glycine > maltose. The effect of these three root exudates on the removal of cadmium-contaminated soils in combination with S. sudanense and P. alopecuroides was also tested. For S. sudanense and P. alopecuroides, the maximum biomass and removal rate reaches the maximum at 100 mmol/L of citric acid. Conversely, low concentrations (approximately 10–50 mmol/L) of glycine and maltose are more effective for plant growth and phytoremediation. The addition of citric acid at 100 mmol/L and approximately 10–50 mmol/L of glycine and maltose can effectively promote the transfer of cadmium ion from roots to leaves and the accumulation of cadmium ion in leaves. [ABSTRACT FROM AUTHOR]

Grazed grass is considered the cheapest feed available for dairy cows in temperate regions, and to maximise profits, dairy farmers must utilise this high-quality feed where possible. Recent research has reported that including white clover (Trifolium repens L.) in grass swards can have a positive effect on milk production. The aim of the present study was to quantify the effect of tetraploid and diploid perennial ryegrass (Lolium perenne L.; PRG) swards sown with and without white clover on the milk production of grazing dairy cows. Four grazing treatments were used for the study; tetraploid-only PRG swards, diploid-only PRG swards, tetraploid PRG with white clover swards and diploid PRG with white clover swards. Thirty cows were assigned to each treatment and swards were rotationally grazed at a stocking rate of 2.75 cows/ha and a nitrogen-fertiliser application rate of 250 kg/ha annually. There was no significant effect of ploidy on milk production. Over the present 4-year study, cows grazing the PRG–white clover treatments had greater milk yields (+597 kg/cow.year) and milk-solid yield (+48 kg/cow.year) than cows grazing the PRG-only treatments. This significant increase in milk production suggests that the inclusion of white clover in grazing systems can be effectively used to increase milk production of grazing dairy cows. Recent research has reported that perennial ryegrass (PRG) ploidy and white clover inclusion in grazing swards can have a positive effect on milk production. In the present study, cows grazing PRG–white clover swards had greater milk yields than did cows grazing PRG-only swards, while grass ploidy had no effect. This significant increase in milk production from PRG–white clover swards suggests that the inclusion of white clover in grazing systems can be effectively used to increase milk production. [ABSTRACT FROM AUTHOR]

Iron is one of the most abundant elements in agricultural soils, but it is mostly present in non-assimilable forms. The dynamics of Fe is determined by several factors, such as organic matter (OM). Dairy slurry is used to increase total OM content in soils. The objective of this study was to determine the effect of applying dairy slurry over a 12-yr period on the levels of available, amorphous, and total Fe in an Andisol soil as indicators of pedogenic alteration. The contents of available (Fed), amorphous (Feox), and total (Fet) Fe were evaluated by selective extractions. A completely randomized experimental design with repeated measures was used, which consisted of six treatments (2, 4, 6, 8, 10, 12 yr) of slurry application and four replicates. A control treatment (no slurry application) was also included with permanent Lolium perenne L. and Trifolium repens L. grasslands. Dairy slurries were applied at a maximum rate of 150 m3 ha-1. Slurry application in the soil significantly increased Fed and OM contents up to 8 yr in the A (8.2 g kg-1 and 15.7%) and B (7.49 g kg-1 and 10.3%) genetic horizons under study; there was a positive correlation between Fed and OM. This would indicate that increased OM would accelerate the pedogenesis of this soil. In general, Fed-ox values were low and there was a significant decrease (p ≤ 0.05) in the 2-, 4-, and 6-yr treatments with values ranging between 1.0 and 0.7 for the Feox:d ratio, indicating increased pedogenesis. [ABSTRACT FROM AUTHOR]

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This study compared the fertiliser effects of different types of liquid anaerobic digestates on the growth of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), and on soil's primary plant macronutrients and microbial abundance. A factorial design with seven fertilisers and one control (five liquid anaerobic digestates, undigested cattle slurry, calcium ammonium nitrate (CAN) 27% N, and no fertiliser) and four plant schemes (monocultures of perennial ryegrass and white clover, a mix of both, and bare soil) were tested. Plant (forage yield, leaf area index (LAI), canopy height and root mass) and soil (concentrations of total N, Morgan's extracted P and K) responses were measured, as well as soil bacterial/archaeal (16S) and fungal (18S) gene copy numbers (GCN). Digestates and cattle slurry with different chemical compositions, when balanced in terms of the quantity of dry matter applied, had comparable forage yield responses (p > 0.05), with higher yields than CAN mostly observed in ryegrass and mixed vegetation (p < 0.05). The presence of white clover contributed to higher soil N (p < 0.05). Soil available P was increased by biofertiliser applications (p < 0.05). Soil available K was influenced by the interaction between biofertiliser and type of plant (p < 0.05), with ryegrass/mixed swards showing lower K concentrations than white clover and bare soil. Soil bacterial (16S) GCN responded to the interaction between fertiliser/vegetation (p < 0.05), while archaeal (16S) and fungal (18S) GCN only to the type of vegetation (p < 0.05). The application of anaerobic digestates showed low direct impacts on the microbial GCN of the soil, mostly influenced by type of vegetation. The biofertilisers showed comparable performances and effects, despite substantial differences between their chemical compositions, indicating a possible complex matrix of interactions between fertiliser-plant-soil-environment. • Different types of anaerobic digestates drove comparable forage yield responses. • Ryegrass showed better response to anaerobic digestates fertilisation than white clover. • Anaerobic digestate application had low influence on soil microbial numbers. • The type of vegetation had strong influence on soil microbial numbers. [ABSTRACT FROM AUTHOR]