White Clover Mixture Research Articles

Effect of Acacia mearnsii forage or tannin extract on rumen dry matter and crude protein degradation.

This study investigated rumen degradation kinetics of dry matter (DM) and crude protein (CP) in compound feed with different tannin extract inclusions and Acacia mearnsi forage (AMF) relative to dairy feeds (perennial ryegrass+white clover mixture pasture, maize silage, lucerne hay and Themeda triandra hay). The compound feed had 0.75%, 1.5% and 3% tannins extract inclusions while the control was a commercial compound feed. Triplicates of each feed per incubation period were incubated in two fistulated Jersey cows for 0, 6, 24, 48, 72, 96 and 120 h, resulting in six replicates per feed. Tannin extract inclusions in compound feed only affected (p < 0.05) the (a) fraction, degradation rate and potential degradability (PD) for DM degradation, and affected (p < 0.05) the (a) and (b) fractions, as well as PD for CP degradation. The (a) fraction and degradation rate for DM degradation changed linearly (p < 0.05). The (a) fraction, PD and effective degradability (ED) of DM degradation changed quadratically (p < 0.05). Except for the degradation rate, the feed type affected (p < 0.05) the degradation parameters in both DM and CP degradations. For DM and CP degradations, (a) fraction was similarly the least in Themeda triandra hay and AMF but similarly the highest in maize silage, perennial ryegrass+white clover mixture pasture and lucerne hay. The (b) fraction was the least in AMF for both DM and CP degradations but the highest for pasture's DM degradation and similarly the highest in maize silage, lucerne hay and T. triandra hay for CP degradation. The PD was the least in AMF for both DM and CP degradations and similarly the highest in pasture DM but similarly the highest in perennial ryegrass+white clover mixture pasture, maize silage and lucerne hay for CP degradation. Furthermore, the ED was the lowest in AMF and the highest for perrenial ryegrass + white clover mixture pasture for DM degradation and same trend was observed for CP degradation whereby perrenial ryegrass + white clover mixture pasture, maize silage and lucerne had the highest ED. Digestible undegraded protein was the highest in AMF and similarly the least in dairy feeds. Tannin source inclusion in ruminant diets should be moderate to prevent rumen DM or CP degradation limitation.

Evaluating the effects of cotton intercropping on cool‐season perennial forage persistence, forage mass, and nutritive value in the southeastern United States

AbstractIntegrated forage–row cropping systems provide important agronomic and economic benefits to producers. However, little attention has been given to incorporating forages into row crop systems unique to the southeastern United States. This study assessed the viability of intercropping cotton (Gossypium hirsutum L.) on perennial, cool‐season legumes during the summer months in the Southeast Coastal Plain over two production years. Treatments included a weedy fallow, annual ryegrass (ARG; Lolium multiflorum Lam.) monoculture, a red clover (RC; Trifolium pratense L.) and white clover (WC; Trifolium repens L.) mixture, and a three‐species mixture of ARG, RC, and WC. Plots were established in fall 2020 with forage grown until May 2021 and 2022, when plots were strip‐tilled and planted with cotton. Cotton was managed with minimal herbicide use to preserve perennial clovers. Results indicated WC was more persistent than RC (&gt;40 plants m−2 vs. &lt;40 plants m−2), and the presence of perennial clovers suppressed weeds at similar levels to the ARG monoculture (35 weeds m−2) during the second spring. Perennial clovers grew taller (4–5 cm) when mixed with ARG. The presence of clovers mixed with ARG during the second spring reduced acid detergent fiber (ADF) concentration and increased crude protein (CP) concentration (280 g ADF kg−1; 167 g CP kg−1) compared to the ARG monoculture (315 g ADF kg−1; 126 g CP kg−1). Benefits of intercropping perennial forages with cotton were maximized during the second year of growth, but future work is necessary to improve stand survival.

Using perennial groundcover crops to suppress weeds and thrips in the southeast cotton belt

AbstractModern cotton production (Gossypium hirsutum L.) in the United States relies on chemical and physical inputs that increase the environmental and monetary costs of managing the crop. Perennial groundcover crops (PGCC) may reduce inputs by persisting in the interrow spaces of the cotton crop during summer months. A 2‐year field study was conducted in Florence, SC, to evaluate growing PGCCs with cotton using a 4 × 4 Latin square consisting of four cover crop treatments: (1) a fallow, unplanted control, (2) annual ryegrass (Lolium multiflorum Lam.) monoculture, (3) a binary red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) mixture, and (4) a trinary mixture of annual ryegrass, red clover, and white clover. Fallow and annual ryegrass treatments were killed with a burndown herbicide application, while treatments containing clovers were mowed. Plots were strip‐tilled and planted with cotton in May each year. Interrow biomass, weed and thrips populations, and perennial clover populations were collected from June to October along with annual lint yields from cotton harvest in October. Results indicated that interrow biomass (2000–3000 kg ha−1), weeds (20 weeds m−2), and thrips (five thrips per five plants−1) populations were lowest in treatments containing perennial clovers, but drought and heat stress reduced clover stands within two growing seasons. Lint yield was not affected by incorporating perennial clovers into the interrow spaces of the crop. Perennial groundcover crops may provide an effective alternative to chemical weed control in cotton, but necessitate management changes to be viable in the southeastern United States.

Plantain dominated in mown mixed swards, but produced less than the original ryegrass-dominant sward

This trial determined the effect of compost on mixed species pasture. Existing (five year old) perennial ryegrass provided the control. A mixture of perennial ryegrass, white clover and plantain was sown into sprayed-out treatment plots, giving five replicates of six treatments. One treatment was direct drilled another was cultivated and drilled. The remaining three were spread with compost (50, 100 or 150 t/hawet weight) and cultivated. Plots were mown at 35 d intervals for two years with clippings returned to the sward. Although grass established well at 500 plants/m2 plantain quickly came to dominate in all renewed plots, at 55-61% of DM in year 1 and 57-79% of DM in year 2. Grass contributed 29-35% of DM in year 1 and 10-30% in year 2, with clover 5-8% in year 1 and 10-14% in year 2. Grass dominated control plots (73and 82% DM, respectively), while clover contributed more DM in absence of plantain (22% and 17%). Compost did not affect production. Cultivation gave a slight advantage over direct drilling, but new swards produced &lt;50% the total DM of the control (P&lt;0.05). Substantial investment was involved, so rewards need to be considerable to recoup costs.

Fatty Acid, Carotenoid and Fat-Soluble Vitamin Composition of Multispecies Swards Grown in Ireland—Implications for a Sustainable Feed in Dairy Farming

Although traditional ryegrass pastures are still commonly used, they require intense management and input and do not perform well during the summer months. Multispecies systems have been recognised as more sustainable, needing less fertiliser and being tolerant to drought and heat. While data on monoculture system fat composition exist, information for multispecies is scarce. The present study compared the fatty acid (FA), carotenoid and fat-soluble composition of a multispecies system (consisting of perennial ryegrass, timothy, white clover, red clover, chicory and plantain) (MULTI) with two other conventional grazing systems (monoculture perennial ryegrass (PRG) and a binary mixture of perennial ryegrass and white clover (PRG+WC)) over the Irish late-summer grazing season of dairy cattle (July–September). The results showed that the three systems had similar levels of FAs (p &gt; 0.05), with mean α-linolenic acid values of 20.00 mg/g in PRG, 18.51 mg/g in PRG+WC, and 17.90 mg/g in MULTI and mean linoleic acid values of 3.84 mg/g in PRG, 4.16 mg/g in PRG+WC, and 4.39 mg/g in MULTI. Fourfold and twofold increases in the concentrations of α-linolenic acid and linoleic acid, respectively, were observed throughout July–September. Variations in stearic acid concentrations were not significant (p &gt; 0.05), and palmitic acid concentrations increased over time (p &lt; 0.05). The average values of lutein (36.68 mg/kg in PRG, 31.26 mg/kg in PRG+WC, and 35.75 mg/kg in MULTI) and α-tocopherol (2.28 mg/kg in PRG, 1.49 mg/kg in PRG+WC, and 1.83 mg/kg in MULTI) were similar among the grazing systems (p &gt; 0.05), and the average β-carotene value was 25% higher in monoculture ryegrass (140.74 mg/kg) than in the multispecies (102.51 mg/kg) (p &lt; 0.05). Nonetheless, the levels of β-carotene found in the multispecies were still above the recommended intake required for ruminants. In conclusion, multispecies pastures could be included in dairy cattle production systems as a sustainable alternative to traditional pastures while also providing typically adequate sources of fats for animal diets.

Managing interspecies competition to improve spring pasture maturity, nutritive value, and biomass

AbstractIn much of the United States, wet springs often cause poor field conditions leading to harvest and/or grazing delays and subsequent reductions in forage nutritive value. The objective of this study was to compare monocultures and combinations of orchardgrass (Dactylis glomerata L.), chicory (Cichorium intybus L.), and white clover (Trifolium repens L.) to determine the effects of interspecies competition on plant maturity, nutritive value, and forage mass over two consecutive springs. It was hypothesized that shade and competition from chicory would delay orchardgrass maturity resulting in greater nutritive value and an extended harvest or grazing window for high‐nutritive value forage. Mixtures containing chicory delayed orchardgrass maturity by at least 9 days in the first spring as compared to orchardgrass monocultures and orchardgrass‐white clover mixtures. Even with decreased chicory mass in the second year (due to drought and winterkill), both 1:1:1 and 4:1:1 (ratio of seeds per hectare) orchardgrass–white clover–chicory mixtures provided greater forage mass and nutritive value (crude protein and net energy) yield over 2 years compared to an orchardgrass monoculture; however, only the 1:1:1 orchardgrass–white clover–chicory mixture provided greater benefits to forage mass and nutritive value yield when compared to orchardgrass–white clover mixtures that are commonly found on farms. This study showed that chicory inclusion provides benefits to orchardgrass and orchardgrass–white clover pastures when planted in appropriate seed proportions; however, increasing chicory longevity will require further investigation to provide continued benefits in perennial cool‐season grass and legume pasture systems.

Yarrow (Achillea millefolium) for low-input lawns in the Mediterranean environment

In recent years, environmental concerns have created a desire for the sustainable care of grass swards, with a specific goal of reducing resources needed for turfgrass maintenance by utilising low-input species best adapted to specific local environmental conditions. A two-year field experiment was conducted to compare the aesthetic or ornamental quality, and function potential, of different swards. The treatments consisted of four monostands of white clover (Trifolium repens L.), yarrow (Achillea millefolium L.), strong creeping red fescue (Festuca rubra L. ssp. rubra Gaudin), and tall fescue (Festuca arundinacea Schreb. = Schedonorus arundinaceus Schreb. Dumort.), three two-species mixtures of white clover + yarrow, white clover + strong creeping red fescue, and yarrow + strong creeping red fescue, and one three-species mixture of white clover + yarrow + strong creeping red fescue. Within each plot, a botanical survey was performed each spring to estimate species relative abundance by determining the proportions of different species present. All plots were evaluated every two weeks during the growing period for visual quality and normalised difference vegetative index. Vegetation canopy height in each plot was measured before each biweekly mowing event, and clippings were collected to measure vegetative dry matter. Relative abundance of yarrow, strong creeping red fescue, and tall fescue was stable throughout the entire study period. The mixtures including yarrow displayed sufficient or higher quality ratings (≥6) in all seasons with the exception of winter, however, yarrow + strong creeping red fescue compensated each other's defects by maintaining their relative abundance (≥ 80%) over time as well suppressing or prevent significant weed invasion (relative abundance <15%). Moreover, yarrow or strong creeping red fescue monostands, or yarrow + strong creeping red fescue could be maintained with lower number of mowing events, due to their lower vertical growth. In conclusion, alternative plant species to turf-type grasses produced a visual quality equal to or better than tall fescue maintained under low fertilisation and mowing frequency. All swards that included yarrow produced better visual quality, exhibited better weed control, had lower vertical growth rate, and provided an aesthetically pleasant, persistent, and sustainable vegetative ground cover than other swards, and can be utilised as a low-input species.

Nitrogen effects on species’ contributions to grazed pasture mixtures under nitrogen loss and application restrictions

New regulations to the use of N fertiliser will impact on seed mixture decisions for new pastures. To help inform these decisions, the effects of N on species and species interactions in pasture mixtures were examined. Ten mixtures of perennial ryegrass (PR), white clover (WC) and plantain (P) were sown on 31 March 2017 and grown ±N fertiliser (275 kg/ha in Year 1 reduced to 200 kg N/ha/year) under grazed and irrigated conditions at Lincoln University. After 4 years, an equi-proportional mixture of PR and WC (based on seed count) optimised average total yield (TY), weed yield (WY), metabolisable energy (ME) and crude protein (CP) regardless of N level. The optimal sowing rate was 12.2 kg PR and 7.0 kg WC/ha. Average TY of the optimal mixture was 20.5 t DM/ha/year with 4% WY, 11 MJ/kg DM ME and 21% CP. Pasture yield and quality responded to change in species proportions away from the optimal mixture, including the addition of P. The magnitude of the TY and WY responses was greater with than without N fertiliser because the identity effects of PR and P, and the way all three species interacted, depended on N level.

Contrasting effects of slurry and mineral fertilizer on N2-fixation in grass-clover mixtures

In dairy systems, grass–clover swards are fertilized with on–farm cattle slurry as a basic dressing and often supplemented with mineral fertilizer throughout the season. Uncertainty remains on consequences for N input from atmospheric N2-fixation by grassland legumes. The aim of this study was to examine the N response of slurry versus mineral N fertilization on clover dynamics, the proportion of N derived from the atmosphere (%Ndfa) and the quantitative N2-fixation (qBNF) using the 15N isotope dilution method. This was done in an on farm setting at two sites in two years with increasing rates of N fertilizer (0–480 kg available N ha-1) either of mineral N only or combined with application of cattle slurry. The leys were at one site composed a 2–species mixture of white clover (Trifolium repens L.) and ryegrass (Lolium perenne L.) and at the other site of a 4–species mixture of white clover, red clover (Trifolium pretense L.), festulolium (Festulolium braunii) and ryegrass. Species dynamics were significantly affected by fertilizer rate in the 2–species sward and by fertilizer rate and type in the 4–species sward. Reduction of the clover proportion in response to fertilization was due to a clover yield decrease (2–species sward) or a grass yield increase (4–species sward). In the 4–species sward, in treatments with mineral N only %Ndfa decreased markedly with N rate, whereas the corresponding slurry + mineral N treatments did not. Thus, apart from fertilization with mineral N only at one site the general picture was a relatively high (>80%) %Ndfa over the season when the N level was below 200–300 kg available N ha-1. The qBNF of the harvested biomass in sward without fertilization reached 193–216 kg N ha-1 in the 2–species sward and 203–286 kg N ha-1 in the 4–species sward. Clover persisted at high fertilization rates, but qBNF was reduced to 16–79 kg N ha-1 and 58–163 kg N ha-1 in 2– and 4–species swards, respectively. Interestingly, in the 4–species sward amended with slurry + mineral N, qBNF was high and independent of fertilization rate. We conclude that response of clover dynamics to N fertilization differed with fertilizer type and level – slurry have lower effect whereas the effect of mineral N only on N2-fixation is less predictable.

Plant diversity with species drilled in the same or alternate rows enhanced pasture yield and quality over 4 years

This paper reports on the effects of plant species diversity and sowing method on pasture yield and quality. Nineteen seed mixtures of perennial ryegrass (PR), plantain (Pl), white clover (WC) and red clover (RC) were sown on 26 March 2015 at Lincoln University. Four mixtures of PR, Pl and WC were repeated with species separated in alternate drill rows. Plots were grazed by sheep and irrigated. After 4 years, a mixture with 25% of each species based on seed count – equivalent to 7.5 kg PR, 5.6 kg Pl, 1.9 kg WC and 4.4 kg RC (19.4 kg total seed)/ha – produced an optimal balance of increased total yield (17.44 t DM/ha/yr), weed suppression (0% of total yield), metabolisable energy (11.4 MJ/kg DM) and crude protein (19% of DM). Sowing method had no effect. Plant diversity enhanced pasture production through positive interactions and identity effects among the legumes (WC and RC) and non-legumes (PR and Pl). The strength of interactions between species depended on the identity and relative abundances of the species involved. The diversity effects occurred alongside shifts in species relative abundances over time. This study demonstrated an experimental basis for the evaluation of multi-species pasture mixtures.

Enhanced efficiency nitrogen formulations for bermudagrass–white clover pastures

AbstractNitrogen fertilizer use is generally restricted in bermudagrass [Cynodon dactylon (L.) Pers.]–white clover (Trifolium repens L.) forage systems because it stimulates grass growth and increases competition with the clover, compromising forage nutritive value and prospective forage accumulation. Enhanced efficiency fertilizer nitrogen (N) products hold potential to improve white clover persistence in bermudagrass–clover pastures while providing supplemental N required by the grass. This study evaluated the effect of different enhanced efficiency N formulations (Environmentally Smart Nitrogen [ESN]; methylene urea; SuperU; and 75% ESN, 25% urea blend) and untreated urea on forage accumulation, nutritive value, and legume persistence in a ‘Wrangler’ bermudagrass and ‘Durana’ white clover mixture. Nitrogen was applied at four rates (0, 112, 224, and 448 kg N ha−1) in two equal applications each year. By the second year, white clover stands were lesser at the greatest N rates. All enhanced efficiency N sources maintained white clover similar to the unfertilized grass–clover control, but only ESN improved white clover persistence over urea. Total season forage accumulation increased linearly with increasing N rates within all three growing seasons, but dry weather conditions in the last 2 yr resulted in less forage accumulation. Nutritive value decreased with maturity throughout the growing season, but ESN maintained clover in the pasture resulted in overall less fiber components and greater digestibility. Although there was no effect of N source on forage accumulation, the ability of ESN to maintain clover could make it a viable option for fertilization in bermudagrass–white clover mixtures.

Methane Emission and Milk Production from Jersey Cows Grazing Perennial Ryegrass–White Clover and Multispecies Forage Mixtures

Methane is a major constituent of greenhouse gas (GHG) emissions from ruminants, and mitigation strategies are needed to alleviate this negative environmental impact while maintaining the environmental and other benefits of grazing systems. Forages containing plant-specialized metabolites (PSM), particularly condensed tannins, may help reduce enteric methane (CH4) emissions. However, information on in vivo CH4 emissions from cows grazing mixtures that contain bioactive herbs is scarce. Accordingly, this study compared a binary mixture of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) against a diverse mixture of six additional species, including tannin-rich species like birdsfoot trefoil (Lotus corniculatus) and salad burnet (Sanguisorba minor), in a full-grazing dairy system. Enteric CH4 emissions were measured using the SF6 tracer technique. Cows grazing diverse mixtures increased their energy-corrected milk (ECM) yield by 4% (p &lt; 0.001) compared with binary mixtures. However, CH4 emissions per kg ECM were also 11% greater for the diverse mixtures (p &lt; 0.05). The very high feed quality and milk yield from both mixtures explained the low CH4 emissions recorded relative to the milk output. The addition of forbs did not provide additional benefits at these intensities, as they were maintained in low yield shares throughout.

Impact of soil management practices on yield quality, weed infestation and soil microbiota abundance in organic zucchini production

In organic farming, reduced tillage aims to maintain the natural fertility of the soil, including its microbiological diversity. Cultivation practices that change the properties of the soil environment determine conditions of plant growth and yield as well as the chemical composition of the biomass. The methods and dates of performing soil cultivation treatments in organic vegetable production were studied in southern Poland, in the years 2016–2018. The following cultivation combinations were applied: conventional autumn ploughing tillage (APT), spring ploughing tillage (SPT), spring rotary tillage (SRT), spring rotary tillage with polypropylene nonwoven (surface mass of 50 g m−2) mulch (SRTPM), and spring rotary tillage with fresh biomass mulch (SRTBM). The experiment was established on a site where a mixture of white clover (Trifolium repens L. cv. ‘RD 84’) and Italian ryegrass (Lolium multiflorum Lam. cv. ‘Gaza’) was grown for green manure, which constituted a forecrop for zucchini (Cucurbita pepo L.) cv. ‘Partenon’ F1. The fresh biomass of clover and grass was used to mulch the soil on the SRTBM plots. It was shown that the spring soil cultivation with a rotary tiller before planting zucchini plants resulted in a higher marketable yield of zucchini fruit compared to the ploughing performed in the spring (an increase by 34.3%) and the ploughing performed in the autumn (an increase by 25.3%), but these differences are not statistically confirmed. The date of ploughing did not significantly affect the extent of weed infestation on the experimental plots. Zucchini fruit harvested in the last year of study (2018) were characterized by the strongest antioxidant activity and contained the highest amount of total phenols. The study demonstrated a beneficial effect of the reduced tillage and mulching with fresh biomass (SRTBM) on bacterial population (1.56 × 109 CFU g−1 DW) in the soil.

Выращивание клевера белого на семенные цели в Кировской области

The results of studies on the formation of seed herbage of white clover varieties Lugovik of the second year of life are presented, the productivity of herbage and seed yield in variants of experiment is given. The yield of green mass differs significantly over the years. This is due to the fact that in 2020 the herbage dried up on the root, it became possible to get good hay. Of all the variants, the highest yield of seeds was collected from plots where white clover grew in its pure form, the lowest yield was in a mixture of white clover with pasture ryegrass. Thus, the cultivation of white clover "Lu-govik" in the conditions of sod-podzolic soils of the Kirov region is more effective in its pure form.

Imaging plant responses to water deficit using electrical resistivity tomography

Background and aimsMonitoring root water uptake dynamics under water deficit (WD) conditions in fields are crucial to assess plant drought tolerance. In this study, we investigate the ability of Electrical Resistivity Tomography (ERT) to capture specific soil water depletion induced by root water uptake.MethodsA combination of surface and depth electrodes with a high spatial resolution (10 cm) was used to map 2-D changes of bulk soil electrical conductivity (EC) in an agronomic trial with different herbaceous species. A synthetic experiment was performed with a mechanistic model to assess the ability of the electrode configuration to discriminate abstraction patterns due to roots. The impact of root segments was incorporated in the forward electrical model using the power-law mixing model.ResultsThe time-lapse analysis of the synthetic ERT experiment shows that different root water uptake patterns can be delineated for measurements collected under WD conditions but not under wet conditions. Three indices were found (depletion amount, maximum depth, and spread), which allow capturing plant-specific water signatures based moisture profile changes derived from EC profiles. When root electrical properties were incorporated in the synthetic experiments, it led to the wrong estimation of the amount of water depletion, but a correct ranking of plants depletion depth. When applied to the filed data, our indices showed that Cocksfoot and Ryegrass had shallower soil water depletion zones than white clover and white clover combined with Ryegrass. However, in terms of water depletion amount, Cocksfoot consumed the largest amount of water, followed by White Clover, Ryegrass+White Clover mixture, and Ryegrass.ConclusionERT is a well-suited method for phenotyping root water uptake ability in field trials under WD conditions.

Productivity and persistence of Kura clover and white clover mixtures with grasses

AbstractThere is a lack of persistent forage legumes for permanent pastures in eastern Canada. Kura clover (Trifolium ambiguum M. Bieb.; KC) is a long‐lived species, with demonstrated potential in various regions, however, there is a lack of information on its performance in mixtures with grasses and no comparisons with white clover (Trifolium repens L.; WC), the main legume species recommended for pastures in eastern Canada. Objectives were to evaluate the potential of KC when grown in mixtures with grasses and compare its performance with WC based‐mixtures and N‐fertilized grass monocultures. Twenty treatments that included KC, WC, and six perennial grasses species (Kentucky bluegrass [Poa pratensis L.; KB], meadow bromegrass [Bromus biebersteinii Roem. &amp; Schult., MB], orchardgrass [Dactylis glomerata L., OR], smooth bromegrass [Bromus inermis L.; SB], tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.; TF], and timothy [Phleum pratense L.; TI]) seeded alone and in binary mixtures were seeded in 2 yr at two sites and monitored for up to four production years. During the first production year, WC‐based mixtures yields were overall greater than those of KC‐based mixtures, while in the second production year and onwards, KC treatments had similar or greater yields than WC, illustrating the greater persistence of KC. Adding KC to grasses also increased total forage yields by 13% on average compared to N‐fertilized solo‐seeded grasses. The performance of specific KC–grass mixtures was variable across sites‐years with no specific mixture being consistently more productive. Kura clover is adapted to contrasting environments of Québec and appears to be a suitable alternative to WC.

White clover population effects on the productivity and yield stability of mixtures with perennial ryegrass and chicory

Due to complementary resource use of the components, grass-clover mixtures are usually higher yielding compared to unfertilized pure grass stands. The number and identity of species in a mixture are known as important factors for the mixture’s productivity. How intraspecific variability of component species affects the productivity of mixtures has received less attention. We established an experiment to investigate how and to what extent different populations of white clover (Trifolium repens L.) affect mixture performance. Eight novel populations of white clover and one variety of perennial ryegrass (Lolium perenne L.) and chicory (Cichorium intybus L.) were grown as monocultures and in two- and three-species mixtures at two sites differing in soil fertility. Aboveground herbage was cut twice in the establishing year and four times in each of the three following years. The accumulated dry matter yield was calculated as the sum of the four annual dry matter yields. There was no significant interaction between white clover population and crop stand (i.e., white clover monoculture or mixtures with partner species) on dry matter yield accumulated over four years; the white clover population that performed well in monoculture also did so in mixtures. At both sites, the binary mixtures of white clover and chicory produced significantly higher dry matter yields than the white clover monocultures and other mixtures. Inclusion of chicory in mixtures significantly increased the stability of yield production as well. Site conditions strongly affected the performance of the forage species mixtures. We found that the benefit of mixtures over monocultures was more related to the identity of species in mixture than to the white clover population.

Under Stressful Conditions, High Cattle Density Maintains White Clover Abundance

Core Ideas Clover richness depends on the grazing management and available water in the topsoil. Clover recovery is not related to the pre‐drought spatial distribution. Tiller density, within a patch, is related to the previous presence of white clover. The steer density adjusts tall fescue and white clover populations in the pasture. ABSTRACTThe aim of the present study was to evaluate the abundance and dynamics of white clover (WC) (Trifolium repens L.) under cattle grazing, in a stressful environment. To this end, we performed a 5‐yr experiment in Buenos Aires province, Argentina, where treatments were low and high forage offers (LFO and HFO) of a tall fescue (TF) [Lolium arundinaceum Schreb. (Darbysh.)]–WC mixture and two sites regarding the initial existence of WC in the pasture (with and without white clover, WC+ and WC–). Climatic conditions determined periods of deficiency or abundance of plant available water in the topsoil, which interacted with the grazing management, leading to either the absence or richness of WC in the pasture. Before a drought, the basal cover of WC was 31.0 and 11.2% with LFO and HFO treatments, respectively (P &lt; 0.001); whereas, during recovery after drought, the corresponding values were 44.0 and 2.7% (P &lt; 0.001), respectively. Re‐establishment of WC at the pasture level was poorly related to the pre‐drought spatial distribution. At the beginning of the experiment, the TF tiller density was greater in WC– sites; whereas, at the end of the experiment, the opposite was observed. The N derived from biological fixation was 85.5% and differences among treatments were of small magnitude. We concluded that, at the pasture level, the abundance of WC in an environment with hot and often dry summers is favored when the competition by TF is controlled and the availability of water in the soil is not limiting.

Buğdaygil ve Baklagil -Buğdaygil Karışımı Meraların Süt İneklerinin Verim Performansı ve Sütün Bileşimine Etkileri

Bu araştırma, Domuz ayrığı (Dactylis glomerata, Pizza, DA), İngiliz çimi (Lolium perenne, Bastion, İÇ) ve Ak üçgül (Trifolium repens, Huia, AÜ) karışımları ile tesis edilen 3 farklı meranın (İÇ, İÇAÜ ve DAAÜ) kuru ot verimi, kimyasal kompozisyonu, süt ineklerinde süt verimi ve sütün kompozisyonuna etkilerinin belirlenmesi amacıyla yürütülmüştür. İki yıl yürütülen bu araştırmada otlatma denemesi, dönüşümlü deneme düzenine göre yapılmıştır. Bu amaçla, her biri 30 günden (8 gün alıştırma ve 22 gün esas dönem) oluşan iki dönemde toplam 6 baş Siyah-Alaca inek (2. laktasyonda ve ortalama 520±26 kg canlı ağırlığında) kullanılmıştır. Hayvanların süt verimi her dönemin birbirini takip eden son beş gününde, sütün besin madde kompozisyonu (kuru madde, yağ ve protein içeriği) ise son üç günü alınan örneklerde tespit edilmiştir. İÇAÜ merasından elde edilen otların asit çözücüde çözünmeyen lif (ADF) içeriği, diğer iki meradan elde edilenlerinkinden daha düşük bulunurken, Net Enerji Laktasyon (NEL) içeriği, birinci yıl, birinci otlatma döneminde, daha yüksek bulunmuştur. Bununla birlikte, incelenen meraların süt verimine etkisi önemsiz, ancak birinci yılda süt protein verimine, ikinci yılda ise süt yağı ve süt kuru maddesine etkilerinin önemli olduğu bulunmuştur. Otlatma döneminin birinci yılında, süt verimi, süt yağı verimi ve protein verimine etkisi ise önemli bulunmuştur. Bu çalışmanın sonuçları, bu çalışma şartları altınında meranın botanik kompozisyonunun sütün miktar ve bileşimi üzerine etkisinin olmadığı ancak, vejetasyon döneminin ilerlemesiyle süt veriminin düştüğü görülmüştür.

Effect of increasing the proportion of chicory in forage-based diets on intake and digestion by sheep

There is a lot of evidence that chicory could be a highly palatable and nutritious source of forage for ruminants, well adapted to climate change and dry conditions in summer, thanks to its resistance to drought and high water content. This study aimed to describe the effect of incorporating chicory to ryegrass or to a ryegrass–white clover mixture on feeding behaviour, digestive parameters, nitrogen (N) balance and methane (CH4) emissions in sheep. In total, three swards of ryegrass, white clover and chicory were established and managed in a manner ensuring the forage use at a constant vegetative stage throughout the experiment. In all, four dietary treatments (pure ryegrass; binary mixture: 50% ryegrass–50% chicory; ternary mixture: 50% ryegrass–25% white clover–25% chicory; and pure chicory) were evaluated in a 4×4 replicated Latin square design with eight young castrated Texel sheep. Each experimental period consisted of an 8-day diet adaptation phase, followed by a 6-day measuring phase during which intake dynamics, chewing activity, digestibility, rumen liquid passage rate, fermentation end-products, N balance and CH4 emissions were determined. Data were analysed using a mixed model and orthogonal contrasts were used to detect the potential associative effects between ryegrass and chicory. The daily voluntary dry matter intake was lower for pure ryegrass than for diets containing chicory (P<0.001) and increased quadratically from 1.39 to 1.74 kg/day with increasing proportion of chicory. Huge positive quadratic effects (P<0.001) between ryegrass and chicory were detected on eating time and eating rate just after feeding indicating an increase of the motivation to eat with mixtures, whereas rumination activity decreased linearly with the proportion of chicory (P<0.001). The organic matter digestibility was similar among treatments (around 80%), but a strong positive quadratic P<0.001) effect was observed on liquid passage rate suggesting that chicory allowed fast particle breakdown in the rumen. Animals fed with the ryegrass–white clover–chicory mixture had the higher urinary N losses (P<0.001), whereas retained N per day or per g N intake was greater when the proportion of chicory was at least 50% (P<0.001) being ~40% greater than for the other treatments. The CH4 yield was lower with pure chicory than with the other treatments (P<0.001) for which emissions were similar. In conclusion, mixing ryegrass and chicory in equal proportions produces a synergy on voluntary intake and an improved N use efficiency likely due to complementarity in chemical composition, increased motivation to eat and faster ruminal particle breakdown.