Legume Mixtures Research Articles

Yield and Nutritive Value of Cool‐Season Annual Forages and Mixtures Seeded into Pearl Millet Stubble

Core Ideas Annual cool‐season forages with high biomass yields may be stockpiled for fall grazing. Species composition was affected by the seeding rates of individual species used within the bulk seeding rate. Controlling millet regrowth with herbicide prior to seeding resulted in greater establishment, yield, and nutritive value of the seeded cool‐season forages. Annual forages can meet the requirements of beef cattle grazing during the fall and early winter. Cool‐season annual forages can provide grazing for beef cattle during fall and early winter. The objective of this study was to evaluate yield and nutritive value of nine forage combinations seeded in early August into pearl millet (Pennisetum glaucum L.) hay stubble that was either sprayed or allowed to regrow. Grass species included spring triticale (×Triticosecale Wittmack), winter wheat (Triticum aestivum L.), and winter barley (Hordeum vulgare L.). Each grass was then combined with a brassica mixture {turnip [Brassicas rapa L. var. rapa], rape [Brassica napus L. var. napus], radish [Raphanus sativus var. oleifer Strokes], and hybrid Chinese cabbage [Brassica rapa L. chinensis) × Turnip]}. A legume mixture (hairy vetch [Vicia villosa Roth] and Austrian winter pea [Pisum sativum subsp. arvense L.]) was then added to the grass–brassica mixtures. All species and mixtures produced sufficient forage (3080–5580 kg dry matter [DM] ha−1) to be stockpiled for fall grazing. The millet and brassicas dominated yield and nutritive value of the unsprayed and sprayed mixtures, respectively. The concentration of neutral detergent fiber (aNDF) was greater in unsprayed than sprayed mixtures (510–579 and 229–246 g kg−1, respectively), but the concentrations of crude protein (CP) (169–180 and 185–202 g kg−1, respectively) and in vitro true digestibility (IVTD) (755–799 and 909–922 g kg−1, respectively) were less. The lesser nutritive value and yield potential associated with letting the millet regrow must be weighed against the extra inputs but greater yield potential and nutritive value when the regrowth is controlled prior to seeding.

The impacts of different management practices on botanical composition, quality, colour and growth of urban lawns

Mulching has increasingly become a standard method used in maintaining low-input lawns. This can be attributed to cost-savings, as these maintenance systems do not require loading and hauling of grass clippings. It is also possible to reduce the amount of nitrogen (N) fertilization and thus save on fertilizer costs. The effects of mowing management and rate of nitrogen fertilization on quality and growth of urban lawns were studied in a field trial during 2007–2012 on lawns newly sown in autumn 2006 and consisting of a grass–legume mixture (Lolium perenne 25%, Poa pratensis 25%, Festuca rubra 30%, Festuca ovina 5%, Anthoxanthum odoratum 5%, Cynosurus cristatus 5%, Trifolium repens 3%, Lotus corniculatus 2%). Nitrogen was used at three application levels: 0, 50 and 100kg of N ha−1year−1. Swards were cut to a height of 40mm five times annually and mulched to the same height. Mulching significantly affected the botanical composition of lawns, wherein a decrease in the portion of legumes (from 32% to 19.1%) was observed. The returned grass matter supported a significant increase in the grass component in the lawns (from 57.8% to 69.7% of total). When the clippings were returned, quality remained the same. Returned clippings had a positive impact on colour and increased the height of cut swards significantly. Application of nitrogen decreased the share of legumes, supported the grass component, statistically increased quality, improved colour, and increased sward height. The results show that returning grass clippings through mulching is beneficial. In any case, it is necessary to apply at least a basal amount of mineral fertilizer in order to preserve the quality of urban lawns over the long term.

Multifunctional benefits of sainfoin mixtures: Effects of partner species, sowing density and cutting regime

AbstractGrass–legume mixtures have proven successful at improving the sustainability of grasslands. Their ability to suppress unsown species is particularly important for sainfoin (Onobrychis viciifolia), a forage crop with valuable bioactive compounds, yet low competitiveness. In this 3‐year study, the suitability of six partner species cultivated in mixtures with sainfoin at different annual numbers of cuts and partner sowing densities were evaluated. Mixture yields outperformed average monoculture yields by 31%, reduced the ratio of unsown species by 65% and increased the symbiotic N2 fixation up to 158 kg ha−1. A key finding of the study was the highly differential patterns of development of the partner grass species over the 3 years. These patterns of development had a large effect on the persistency of the proportion of sainfoin in the mixtures, which varied in the third year between 17% (when grown with Dactylis glomerata) and 38% (with Lolium perenne). These findings contribute to the further development of sustainable grass–legume systems, as evidence for the successful cultivation of sainfoin as an alternative legume species can help diversification, and knowledge of mixture development supports more persistent legume proportions.

Effects of vineyard floor cover crops on grapevine vigor, yield, and fruit quality, and the development of the vine mealybug under a Mediterranean climate

The influence of complete cover cropping (inter- and intra-row) on grapevine growth, yield and must quality was evaluated in a three-year field trial in a commercial vineyard in northwestern Sardinia (Italy). Effects on developmental and reproductive parameters of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), were also investigated. The cover crop treatments were: natural covering, legume mixture, grass mixture, and conventional soil tillage, which was included as the reference treatment. Relative to soil tillage, cover crops reduced grape production by modifying yield components in different ways: legume mixture reduced the cluster weight, whereas grass mixture led to a lower number of clusters per vine coupled with a lower cluster weight. Cover crops also altered the must qualities relative to soil tillage. Grass mixture increased the content of sugar, anthocyanins and polyphenols, whereas legume mixture and natural covering reduced total polyphenols and anthocyanin content, respectively. All the P. ficus biological parameters examined were affected by the floor management practices. Mealybugs reared on grapevines subjected to soil tillage and legume covering showed a faster development time and higher survival, fecundity and fertility than those developed on natural covering and grass plots. The vine mealybug showed a higher performance on grapevines with a higher nitrogen content and vigor. Effects of cover crop treatments appear to be mediated through nutrient availability and content in grape plants. Consequently, utilizing competitive cover crops, while reducing yields, would improve must quality and reduce pest development.

Survival and Habitat Use of Wild Pheasant Broods on Farmland in Lower Austria

Wild pheasants (Phasianus colchicus) have declined throughoutmuch of their European distribution. The influence of habitat composition on survival and habitat use of wild pheasant broods is not well understood, but is important for population management. We studied the brood-rearing ecology of pheasants using radio-tagged hens on a 2,400 ha farming estate in Lower Austria during 2001-2003. Brood survival , ≥ 1 chick surviving to 3 weeks, (n = 36) were: 74.4% (15.6 SE), 91.9% (7.8 SE), and 65.7% (13.8 SE), during 2001-2003, respectively. Complete brood loss (n = 7) occurred between 2 -17 days after hatching with predation (n = 5) accounting for 71.4% of losses. Survival of broods was influenced by composition of habitats within fixed kernel home ranges. Proportion of planted game crop, mixture of legumes and grasses, within the home range had a positive effect on survival, whereas age and condition of females did not influence brood survival. To improve brood survival rates of pheasants in agricultural landscapes farmers and game managers should consider planting specialist brood rearing mixtures in areas close to nesting habitat.

Incidencia de variables biológicas y edáficas en el establecimiento de mezclas forrajeras

With the aim of evaluating the incidence of biological and edaphic factors on the establishment of forage mixtures, a trial was set consisting in 180 sites in the states of Florida, Durazno and Lavalleja, Uruguay. The percentage of establishment was measured 90 days after seeding through the percentage of emergency, in three types of mixtures: a) perennial grass and legumes; b) perennial grass and legumes, and annual ryegrass; c) perennial grass and legumes, and wheat. Biological (predecessor crop, predecessor crop stubble, date of seeding, species sown) and edaphic (organic matter, pH, phosphorus) factors were quantified to determine their effects on the establishment period of the sowed seeds. This period was 29.2% for all the sites and species. Type of predecessor crop and species sowed (Festuca arundinacea Schreb., Dactylis glomerata L., Trifolium repens L., Trifolium pratense L., Lotus corniculatus L., Medicago sativa L., Lolium multiflorum Lam., Triticum aestivum L.) in the mixtures were determinant in the establishment percentage of the mixtures (perennial grass and legumes). Annual grasses reached the highest establishment percentage (50%) but supressed perennial grasses. Setaria italica (L.) P. Beauv., was the best predecessor crop allowing an establishment of 40% in a mixture of perennial grass and legumes. On the other hand, Lotus corniculatus achieved the lowest establishment (14%). A negative correlation was found between legume establishment and a pH lower than 5.9.

Performance of lucerne genotypes for biomass production and nitrogen content differs in monoculture and in mixture with grasses and is partly predicted from traits recorded on isolated plants

Grass–legume mixtures are key crops to improve agricultural sustainability. Despite their significant use in mixture, lucerne (Medicago sativa L.) varieties are mostly tested and bred for monocultures. This study was performed to evaluate whether the ranking of lucerne genotypes for biomass components and quality was similar in monoculture and mixture, and whether traits recorded on isolated plants could help to predict performance in monoculture and mixture. For 46 genotypes planted in the three competition conditions, plant biomass, shoot height, shoot number and protein content were recorded. In addition, maximum leaf size, internode length, stem diameter, growth habit, specific leaf area and leaf dry-matter content were measured on isolated plants. A general positive correlation was observed between the performance of genotypes in monoculture and in mixture. However, significant changes in genotype ranking indicated that the species of its neighbours could modify the relative performance of a genotype. The traits that minimised competition intensity also changed according to the neighbour species. In mixture, competition intensity was highest for plants with long internodes, a high shoot number and a non-erect growth habit. In monoculture, plants with long internodes and larges leaves suffered less from competition. The agronomic performance of lucerne varieties differing in their architecture should be compared in monoculture and mixture to finally identify the traits to be phenotyped to improve lucerne variety performance in both cultivation modes.

Effect of Barley, Italian ryegrass and Legume Mixture on Nitrogen Fixation and Transfer to Grasses on Spring Paddy Field using Isotope Dilution and Difference Method

Effect of Barley, Italian ryegrass and Legume Mixture on Nitrogen Fixation and Transfer to Grasses on Spring Paddy Field using Isotope Dilution and Difference Method

Nitrogen status of functionally different forage species explains resistance to severe drought and post-drought overcompensation

Forage species of intensively managed temperate grassland differ substantially in their drought responses. We investigated whether differences in resistance and resilience, based on biomass yield, are related to species nitrogen (N) acquisition and drought-induced N deficiency.A three-factorial field experiment was established with monocultures of four species (first factor) that differed in functional traits regarding N acquisition and rooting depth: Lolium perenne L. (shallow-rooted non-legume), Cichorium intybus L. (deep-rooted non-legume), Trifolium repens L. (shallow-rooted legume), and Trifolium pratense L. (deep-rooted legume). A ten-week summer drought was simulated (second factor) and compared to a rainfed control during two regrowths under drought and one regrowth during a subsequent six-week post-drought period. The distribution of applied fertiliser N (200kgha−1year−1 in total) was manipulated (third factor) with plots receiving no N during drought or 60kgNha−1.Soil water availability during drought became increasingly restricted over time. Plant-available soil N was reduced up to 4- and 12-fold during the first and second regrowths under drought, respectively, but was increased up to 4-fold during the post-drought regrowth, compared to rainfed control conditions. Legumes were consistently less N-limited than non-legumes (P<0.001). Nitrogen derived from the atmosphere (Ndfa) in the legume T. repens was 72% under severe drought (first regrowth under drought). Here, legumes were rather drought-resistant (biomass yield under drought was −22% compared to the rainfed control), while non-legumes were not (−41%). Further, N fertilisation mitigated the negative drought effect on biomass yield of non-legumes from −41% (no N under drought) to 23% (N under drought). Under extreme drought (second regrowth under drought), all species were strongly impaired, irrespective of N fertilisation (−75% on average); yet, Ndfa in T. repens was still 56%. During the post-drought regrowth, former drought-stressed non-legumes overcompensated and revealed +53% higher yield than the control.The interspecific differences in plant species responses to drought suggest a shift from N limitation under severe drought to water limitation under extreme drought. Because legumes were able to compensate for drought-induced restrictions in yield through symbiotic N2 fixation, and non-legumes overcompensated during post-drought, cropping selected legumes in mixtures with non-legumes could improve resistance and resilience of forage swards against severe drought events.

Ecological Restoration of Coal Mine‐Degraded Lands in Dry Tropical Climate: What Has Been Done and What Needs to Be Done?

In developed countries, ecological restoration is a widely accepted practice to restore the productivity of degraded coal mine spoils and prevent mine‐degraded sites from acting as sources of pollution. During the past decade, ecologists realized the global need for ecological restoration, and the benefit of restoration is now assessed on the basis of ecosystem services that the restored lands can provide. In this article, the knowledge gap between crude reclamation and ecological restoration is examined, the steps crucial to ecological restoration in tropical conditions are identified, and simple guidelines are given for easy understanding. Restoration issues, such as modification of the forestry restoration approach, reestablishment of biodiversity, removal and reuse of topsoil during progressive and final stages of ecological restoration, drainage, promotion of a plant‐succession‐based approach, use of a grass–legume mixture as an initial colonizer, stabilization of steep slopes, and soil blanketing, are discussed. Those attributes of a degraded ecosystem that are responsible for the success of any restoration project are critically examined, and the opportunities provided by ecological restoration are explored.

Estimation of glycemic carbohydrate and glycemic index/load of commonly consumed cereals, legumes and mixture of cereals and legumes

Aim of the present study is to estimate glycemic carbohydrates and develop data base on glycemic index and glycemic load (GI and GL) of commonly consumed cereals and legumes by using Food and Agriculture Organization (FAO) or World Health Organization (WHO) methods. The results of glycemic carbohydrates in rice was 79.22 %, wheat 63.26 % and pulses in the range from 51.24 % (green gram) to 56.22 %, (chana dhal), mixed dhal 40.09 %, wheat + chana dhal (60:40) 49.94 %, wheat + chana dhal + barley (40:30:30) was 46.89 %, respectively. The results of GI and GL of rice were the highest (GI–78.23, GL–49.38), followed by wheat chapatti (GI–65.66, GL–32.83). The pulses tested were showing lower values ranging from (GI–37.95 to 43.01 and GL–18.97 to 21.50), mixed dhal (GI–43.64, GL–21.82), wheat + chana dhal (60: 40) (GI–32.37, GL–16.18), wheat + chana dhal + barley (40:30:30) GI–39.27, GL–19.63, respectively. The results of the study indicated that pulses have low glycemic indices and glycemic loads, hence, could be safely used in the diet of diabetic patients.

Anaerobic co‐digestion of perennials: Methane potential and digestate nitrogen fertilizer value

AbstractCo‐digestion of crop biomass improves the traditional manure‐based biogas yield due to an increased content of easily degradable carbon compounds. In this study, the methane potential of three perennials (grass, legumes, and grass+legume) was determined using various amounts together with animal manure. The nitrogen (N) mineralization dynamics in soil and the N‐fertilizer value of the derived digestates were subsequently tested in both a soil incubation study and a pot experiment with spring barley. Digestion of all tested perennials together with a manure‐based inoculum increased the cumulative methane yield four to five times compared to digestion of the inoculum alone, with the highest increases observed with pure grass. However, the methane potential decreased along with increasing grass biomass concentration. In the plant pot experiment, all tested digestates increased barley shoot biomass by 40–170%, to an extent statistically comparable to mineral N fertilizer. However, the application of the digestate originating from fermentation with pure grass resulted in lower plant growth and a more fluctuating soil mineral N content throughout the incubation study compared to the other digestates. Considering the high dry matter and methane yield ha−1, the possibility to substitute mineral N fertilizer inputs by leguminous biological N2 fixation capacity, and the digestate fertilizer value, the integration of grass–legume mixtures or sole legumes into anaerobic digestion systems as co‐substrate for manure seems to be promising. This could furthermore contribute to the diversification of cropping systems for bioenergy production.

A meta-analysis of relative crop yields in cereal/legume mixtures suggests options for management

Intercrops of cereals and legumes are grown worldwide, both in smallholder agriculture in developing countries and in organic farming systems in developed countries. The competitive balance between species is a key factor determining productivity in mixtures. Management factors, e.g. sowing time, sowing density and rate of N fertilizer, affect the relative competitiveness and performance of intercropped species. There is a need for an overarching analysis to elucidate general principles governing the relative performance of legumes and cereals in mixtures. We therefore conducted a meta-analysis of published studies to explore how the relative yield of legumes and cereals in mixtures responds to relative sowing time, relative density and nitrogen fertilizer.An index for relative sowing time, RST, was developed to quantify the relative difference in sowing time between the intercropped species. RST is defined as the amount of time that a species is sown earlier or later than its companion species, relative to the length of its own growing period. RST is smaller than zero if a species is sown earlier than its companion species and greater than zero if it is sown later. Relative performance of a species was characterized by its relative yield (or partial land equivalent ratio, PLER) in the intercrop compared to the yield in the sole crop.In 409 out of 552 cases, the cereal had a greater relative yield than the legume. Sowing a species earlier than its companion increased its relative yield, and vice versa. An increase in density of a species increased its relative yield and decreased the relative yield of the companion species. The relative yield of cereals increased and that of legumes decreased with the amount of N fertilizer. The negative effect of N on the relative yield of legumes was mitigated if the legume was sown before the cereal.The study shows how the performance of cereals and legumes in an intercrop is affected by sowing densities, relative sowing times, and nitrogen fertilizer. Growers can exploit these relationships to manage competition between cereals and legumes in mixtures and enhance species complementarity, total productivity and economic profit.

Effects of including forage herbs in grass–legume mixtures on persistence of intensively managed pastures sampled across three age categories and five regions

ABSTRACTTo test the hypothesis that the inclusion of the forage herbs chicory (Cichorium intybus L.) or plantain (Plantago lanceolata L.) or both in a grass–legume pasture mix improves persistence of sown vegetation and reduces weed and invertebrate pest ingress, a study was undertaken in 31–44 intensively managed pastures in each of five regions in New Zealand (Northland, Waikato, Bay of Plenty, Taranaki and Canterbury). The regions were stratified according to farm type (dairy or sheep and beef), pasture type (sown with grasses, legumes and herbs or grasses and legumes) and pasture age (young: 1–2 years old; medium: 3–4 years old; and old: 5+ years since sowing, n = 171). Sown species ground cover and emergence from the soil seed bank was greater, and unsown species ground cover and emergence lower, in sheep and beef pastures sown with herbs than without herbs (78% vs 68% ground cover, respectively, averaged over all pasture ages), but there was no difference between pasture types on dairy farms. Invertebrate predator and parasitoid abundance was 65% greater under pastures sown with herbs than without herbs. The number and % dry matter contribution of sown species decreased, and that of unsown species increased, as pastures aged. Unsown species comprised 90% (sheep and beef) and 98% (dairy) of total seedling emergence. The inclusion of forage herbs increased persistence of sown species and reduced weed ingress, but only on sheep and beef farms.

Evaluation of Alfalfa–Tall Fescue Mixtures across Multiple Environments

Binary grass–legume mixtures can benefit forage production systems in different ways helping growers cope both with increasing input costs (e.g., N fertilizer, herbicides) and potentially more variable weather. The main objective of this study was to evaluate alfalfa (Medicago sativa L.) and tall fescue [Schedonorus phoenix (Scop.) Holub] mixtures across a wide range of environments to assess herbage accumulation, weed suppression and fertilizer nitrogen replacement values (FNRV). A common field experiment was established in 2009 and 2010 at six study sites in the United States: Maryland, Pennsylvania, Utah, Virginia, Wisconsin, and Wyoming. Experimental treatments included an alfalfa monoculture, three alfalfa–fescue mixtures with seed ratios of 75:25, 50:50, and 25:75 of alfalfa/tall fescue, and tall fescue monocultures that received nitrogen applications of 0, 50, 100, 150, 200, and 300 kg N ha–1, respectively. Data were collected over a 2‐yr period. The responses of tall fescue monocultures to N fertilization differed among sites, and this contrasted with mixture yields, which did not exhibit site × treatment interactions (P &gt; 0.05). Herbage accumulation and weed suppression were consistently higher in mixtures compared with alfalfa monocultures and tall fescue monocultures receiving less than 100 kg N ha–1. The FNRVs for alfalfa were within the range reported for other studies and averaged 143 kg N ha–1. The consistent herbage accumulations across these multiple environments suggest binary mixtures of alfalfa–tall fescue may be a good option for many forage–livestock producers although yields could be improved with location specific cultivar selection.

The North Wyke Farm Platform: effect of temperate grassland farming systems on soil moisture contents, runoff and associated water quality dynamics.

SummaryThe North Wyke Farm Platform was established as a United Kingdom national capability for collaborative research, training and knowledge exchange in agro‐environmental sciences. Its remit is to research agricultural productivity and ecosystem responses to different management practices for beef and sheep production in lowland grasslands. A system based on permanent pasture was implemented on three 21‐ha farmlets to obtain baseline data on hydrology, nutrient cycling and productivity for 2 years. Since then two farmlets have been modified by either (i) planned reseeding with grasses that have been bred for enhanced sugar content or deep‐rooting traits or (ii) sowing grass and legume mixtures to reduce nitrogen fertilizer inputs. The quantities of nutrients that enter, cycle within and leave the farmlets were evaluated with data recorded from sensor technologies coupled with more traditional field study methods. We demonstrate the potential of the farm platform approach with a case study in which we investigate the effects of the weather, field topography and farm management activity on surface runoff and associated pollutant or nutrient loss from soil. We have the opportunity to do a full nutrient cycling analysis, taking account of nutrient transformations in soil, and flows to water and losses to air. The NWFP monitoring system is unique in both scale and scope for a managed land‐based capability that brings together several technologies that allow the effect of temperate grassland farming systems on soil moisture levels, runoff and associated water quality dynamics to be studied in detail.Highlights Can meat production systems be developed that are productive yet minimize losses to the environment?The data are from an intensively instrumented capability, which is globally unique and topical.We use sensing technologies and surveys to show the effect of pasture renewal on nutrient losses.Platforms provide evidence of the effect of meteorology, topography and farm activity on nutrient loss.

Perennial species mixtures for multifunctional production of biomass on marginal land

AbstractMultifunctional agriculture provides noncommodity functions and services along with food, feed and bioenergy feedstocks, for example by preserving or promoting biodiversity, improving soil fertility, mitigating climate change and environmental degradation, and contributing to the socio‐economic viability of rural areas. Producing biomass for bioenergy from low‐input perennial species mixtures on marginal land has the potential to support biodiversity and soil carbon sequestration in synergy with greenhouse gas mitigation. We compared biomass production in species‐rich mixtures of perennial grasses, legumes and forbs with pure‐stand grasses and relatively species‐poor mixtures under different nitrogen fertilization regimes. Field experiments were performed on different types of marginal land, that is agricultural field margins and land with poor soil fertility, at four sites in southernmost and western Sweden. Biomass production was measured for three years in perennial grasses grown as pure stands, in legume‐grass mixtures, and legume‐grass‐forb mixtures across a species richness gradient. In unfertilized species‐rich mixtures, average biomass yields per experimental site and year were in the range from 3 to 9 metric ton DM ha−1 yr−1. While the most productive pure‐stand grasses fertilized with 60–120 kg N ha−1 yr−1 often produced higher biomass yields than unfertilized mixtures, these differences were generally smaller than the variations between years and sites. Calculations of climate impact using the harvested biomass for conversion to biogas as vehicle fuel showed that the average greenhouse gas emissions per energy unit were about 50% lower in unfertilized systems than in treatments fertilized with 100–120 kg N ha−1 yr−1. Our findings thereby show that unfertilized species‐rich perennial plant mixtures on marginal land provide resource‐efficient biomass production and contribute to the mitigation of climate change. Perennial species mixtures managed with low inputs thus promote synergies between productivity and biodiversity in the perspective of climate‐smart and multifunctional biomass production.

Fatty acid composition of ruminal digesta and longissimus muscle from lambs fed silage mixtures including red clover, sainfoin, and timothy.

This work investigated the effects of feeding silage mixtures of a plant containing polyphenol oxidase (PPO; red clover [; RC]), a plant containing tannins (sainfoin [; SF]), and a grass species not containing these compounds (timothy [; T]) on ruminal and intramuscular (i.m.) fatty acids of lambs. Forty 4-mo-old castrated male Romane lambs, divided into 5 groups, received 1 of the following silages: 1) T (100%), 2) a binary mixture of timothy and tannin-containing sainfoin ( cv. Perly; 50:50 [T-SF]), 3) a binary mixture of timothy and PPO-containing red clover ( cv. Mervius; 50:50 [T-RC]), 4) a ternary mixture of timothy, sainfoin, and red clover containing both tannins and PPO (50:25:25, respectively [T-SF-RC]), and 5) a binary mixture of tannin-containing sainfoin and PPO-containing red clover (50:50 [SF-RC]). In the rumen digesta, the partial or total replacement of T with forage legumes was associated with greater concentrations of PUFA ( < 0.001) and 1esser concentrations of MUFA ( < 0.001). The inclusion of forage legumes in the silage favored the accumulation of 18:3 -3 ( < 0.001), with the greatest concentrations being observed in SF-RC. This latter diet also led to the greatest percentage of 18:2 -6 ( < 0.001). Forage legumes decreased the -11 18:1 to 30% of T in rumen digesta ( < 0.001). Forage legumes decreased the total concentration of branched-chain fatty acids in the rumen digesta (on average, -28%; < 0.001), this effect being less marked (-17%; = 0.014) in T-RC in comparison with T. The dietary treatment tended to affect the proportion of MUFA ( = 0.081) and of PUFA ( = 0.079) in the i.m. fat of the LM, respectively, at the highest and lowest numerical value in the T group. The sum of -3 fatty acids was less in the T and T-SF groups compared with the mixture of legumes without T (SF-RC; < 0.001 and < 0.008, respectively). The latter group had also a lesser -6-to--3 ratio than the T-SF group ( = 0.01). -11 18:1 was greater ( < 0.03) in lambs given T as the sole silage in comparison with lambs given T-RC, T-SF-RC, and SF-RC. Rumenic acid (-9 -11 CLA) was detected at a greater percentage in the LM from the animals fed the T silage compared with animals fed the T-SF-RC treatment ( = 0.004). Contrarily, -9 -12 -15 18:3 was found at a greater concentration in the muscle from lambs in the SF-RC treatment compared with lambs in the other treatments ( < 0.001). Furthermore, the T-RC group showed a greater proportion of α-linolenic acid than the T group ( = 0.03). In conclusion, the effects of the 2 active compounds (PPO and tannins) appear to be similar and additive. Moreover, a silage composed of a mixture of RC and SF is an excellent forage for growing lambs in terms of i.m. fatty acid composition.

Above-Belowground Herbivore Interactions in Mixed Plant Communities Are Influenced by Altered Precipitation Patterns.

Root- and shoot-feeding herbivores have the capacity to influence one another by modifying the chemistry of the shared host plant. This can alter rates of nutrient mineralization and uptake by neighboring plants and influence plant–plant competition, particularly in mixtures combining grasses and legumes. Root herbivory-induced exudation of nitrogen (N) from legume roots, for example, may increase N acquisition by co-occurring grasses, with knock-on effects on grassland community composition. Little is known about how climate change may affect these interactions, but an important and timely question is how will grass–legume mixtures respond in a future with an increasing reliance on legume N mineralization in terrestrial ecosystems. Using a model grass–legume mixture, this study investigated how simultaneous attack on lucerne (Medicago sativa) by belowground weevils (Sitona discoideus) and aboveground aphids (Acyrthosiphon pisum) affected a neighboring grass (Phalaris aquatica) when subjected to drought, ambient, and elevated precipitation. Feeding on rhizobial nodules by weevil larvae enhanced soil water retention under ambient and elevated precipitation, but only when aphids were absent. While drought decreased nodulation and root N content in lucerne, grass root and shoot chemistry were unaffected by changes in precipitation. However, plant communities containing weevils but not aphids showed increased grass height and N concentrations, most likely associated with the transfer of N from weevil-attacked lucerne plants containing more nodules and higher root N concentrations compared with insect-free plants. Drought decreased aphid abundance by 54% but increased total and some specific amino acid concentrations (glycine, lysine, methionine, tyrosine, cysteine, histidine, arginine, aspartate, and glutamate), suggesting that aphid declines were being driven by other facets of drought (e.g., reduced phloem hydraulics). The presence of weevil larvae belowground decreased aphid numbers by 30%, likely associated with a significant reduction in proline in weevil-treated lucerne plants. This study demonstrates how predicted changes to precipitation patterns and indirect interactions between herbivores can alter the outcome of competition between N-fixing legumes and non-N-fixing grasses, with important implications for plant community structure and productivity.

The effect of catch crops cultivated in accordance with the agri-environment scheme on weed infestation of spring wheat stand

The aim of the conducted study was to assess the effect of two types of stubble catch crops (a mixture of legumes and white mustard) as well as varied nitrogen fertilization on weed infestation of a spring wheat stand depending on the adopted tillage system. Weed infestation assessed at the tillering phase of spring wheat showed the lowest number of weeds in direct sowing after the mixed legume catch crop. The next assessment of weed infestation performed at the flowering phase of spring wheat showed that the lowest number of weeds was found in direct sowing immediately after the catch crop of a mixture of legumes and white mustard for the complete nitrogen fertilization rate. The lowest weed dry weight was recorded in conventional tillage after a mixture of legumes for the complete nitrogen fertilization rate and after white mustard for a reduced nitrogen fertilization rate.