Symbiotic Nitrogen Fixation of White Clover in a Mixed Sward is not Limited by Height of Repeated Cutting

The aim of this study was to investigate whether symbiotic nitrogen fixation in white clover nodules limits nitrogen supply and hence clover growth by repeated defoliation at two cutting heights. Other possible factors governing symbiotic nitrogen fixation in the field were also elucidated. Using ¹⁵N, a 2-year field experiment including white clover ( Trifolium repens L. cv. Ladino) and perennial ryegrass ( Loliumperenne L. cv. Bastion) in monocultures and in mixtures was conducted in Eschikon, Switzerland. The effect of two cutting heights (4 cm and 10 cm above ground level) on the performance of symbiotic nitrogen fixation of white clover in the different sward-types was investigated. After each harvest, the plots were fertilized with 3 g N m^-2(equivalent to 30 kg N ha^-1 cut^-1 or 210 kg N ha^-1 year^-1). In both years, white clover grown in a mixture with grass received a significantly higher percentage of nitrogen from symbiotic fixation compared with clover grown in monoculture. This phenomenon is attributed to the strong competitiveness of ryegrass in soil nitrogen uptake. Consequently, white clover in the clover-ryegrass mixture was more dependent on symbiotic nitrogen fixation than that grown in monoculture. The cutting height did not preferentially influence symbiotic nitrogen fixation, as opposed to the uptake of mineral nitrogen from the soil. From this finding it is suggested that symbiotic nitrogen fixation did not limit the supply of nitrogen to clover and hence its growth. It is proposed that symbiotic nitrogen fixation in white clover is regulated by the demand for nitrogen rather than by the availability of carbohydrate reserves in the stolons. Symbiotic nitrogen fixation should thus be looked upon as an integrated plant growth factor and not as an isolated phenomenon.     

Performance of Timothy-based Grass/Legume Mixtures in Cold Winter Region

This study sought to identify grass/legume mixtures that increase the yield and persistence of forage stands with improved nutritive quality in cold‐winter regions, compared with the standard mixture of timothy (Phleum pratense L.)/red clover (Trifolium pratense L.)/alsike clover (Trifolium hybridum L.). Timothy was mixed with either perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis L.) or Kentucky bluegrass (Poa pratensis L.). The legumes in mixtures were red clover, alfalfa (Medicago sativa L.) or white clover (Trifolium repens L.). Averaged over three production years, the majority of mixtures had greater dry matter (DM) yields than the standard (8.35 t ha^?1). Timothy, grown alone and in three mixtures, outyielded the standard by 19–30 %. Yield reductions in mixtures over the 3‐year period were greatest with red clover, and least with bluegrass. Mixtures with alfalfa were highest in nitrogen (28.4 g kg^?1), while grasses grown alone (24.6 g kg^?1) and the standard mixture (25.1 g kg^?1) were the lowest in N. Mixtures with red clover or alfalfa had the least neutral detergent fibre (NDF), averaging 418 and 429 g kg^?1 respectively. Mixtures including white clover were initially low in NDF at 347 g kg^?1 in year 1 but increased to 550 g kg^?1 in year 3 as white clover composition declined in the sward.     

Assessment of Cattle Preference for Perennial Ryegrass Varieties in Association with White Clover. Does White Clover Content Interfere?

There is a need to evaluate grass varieties under grazing management to allow selection of varieties to increase animal performance. However, the evaluation of animal performance under grazing with each variety is arduous and time-consuming. An alternative is to describe the preference by grazing animals when given a choice of different varieties. Indeed, there is some indications that preference is related to variety characteristics such as leaf content or digestibility, characteristics having also an impact on the level of intake of this variety. However, preference for grass varieties, when sown alone, may not reflect agricultural practice as grasses often occur in mixed swards, associated with white clover. So, the aim of the present work was to determine whether, under grazing management, cattle expressed selections when given a choice of mixed swards in which different perennial ryegrass varieties were grown in association with a common white clover variety at two levels of fertilizer application (60 or 160 kg N ha⁻¹ annum⁻¹). The preference for perennial ryegrass variety per se was then assessed after taking white clover content into consideration. The results show that there were significant differences in preference for perennial ryegrass varieties, per se, even for varieties with the same heading date and ploidy. The effect of white clover cover on sward selection was more marked in swards which received the higher level of nitrogen fertilizer application which may have been related to a more variable white clover content between swards. This suggests that, under low nitrogen fertilizer application, differences in perennial ryegrass varieties preference can be determined in the same experiments as are used to determine ryegrass varieties persistence in association to white clover. Nevertheless, before such ‘variety preference’ tests can be applied in practice, a validation of the possible correlation between ‘variety preference’ and ‘variety intake’ will be necessary.     

Effects of Competition upon the Productivity of White Clover-Perennial Ryegrass Mixtures. Analysis of and Interrelations between Characters

A diallel crossing programme amongst tour contrasting white clover varieties was used to generate material for studying the interrelationships amongst those characters which affect the productivity of white clover- perennial ryegrass mixtures under a cutting-only management regime. Such a regime favoured clover growth. All the clover characters exhibited strong positive correlations with mixture yield. However, this combination of clover characters did not promote growth of the grass companion. For this a low growing variety with a dense stolon network appeared preferable. Path analysis indicated that differences existed between the two companion grass varieties used for this experiment in their upon clover characters.     

The Persistence of Tetraploid Perennial Ryegrass in a Mixture with Diploid Perennial Ryegrass

An investigation was carried out into the survival of two tetraploid varieties of perennial ryegrass ( Lolium perenne L.), sown in a mixture with a diploid and very intensively grazed for over five years.
Mixture M1 consisted of the late heading varieties Meltra and Vigor , and mixture M2 of the early heading varieties Merlinda and Melino.
The ploidy was determined by microscopic analysis.
The share of the tetraploid component decreased in both mixtures. The decrease was more pronounced in the early heading mixture. Information was also sought on the technique of sampling such swards.     

Nitrogen Uptake by Italian Ryegrass after Destruction of Non-fertilized Set-aside Covers at Different Times in Autumn and Winter

The introduction of the European set-aside into the rotation can modify the nitrogen availability for subsequent crops. With a view to evaluating this effect, three non-fertilized covers were sown in May 1995. These covers were ploughed in at three different times: October 1995, December 1995 and March 1996. The ploughed-in nitrogen quantities did not vary greatly with destruction time. The greatest quantities were incorporated into red clover plots and the smallest quantities into perennial ryegrass plots. The C/N of perennial ryegrass was on average 24 and that of red clover 14.
The soil cover by clover just before ploughing is significantly related to the ploughed-in nitrogen quantities.
An Italian ryegrass was sown as the subsequent crop to the set-aside. Overall, during the whole year 1996 and 1996–1997, there was no difference between the yields for different destruction times except for the first cut of 1996.
The highest production was obtained after red clover and the lowest after perennial ryegrass. The relationship between the nitrogen amount or C/N of the ploughed-in material and the nitrogen export for the annual harvest of Italian ryegrass showed highly significant correlations in 1996 as well as for the 2-year harvest. Two multiple regressions were calculated in order to take into consideration the characteristics of the ploughed-in material of the set-aside.
The measured percentage of soil cover by clover before ploughing and the annual nitrogen export of Italian ryegrass were also significantly related in 1996 and for both years.     

生草栽培对柑桔丛枝菌根形成及果实品质的影响

试验以枳砧锦橙(CitrussinensisOsbeck.)初结果树为试材。试验设4个处理,分别为柑桔园间作百喜草(Bahiagrass)(PaspalumnotaturnFlugge)、白三叶草(Whiteclover)(TrifoliumrepensL.)、紫花苜蓿(Alfalfa)(MedicagosativaL.)和多年生黑麦草(Perennialryegrass)(LoliumperenneL.),以清耕为对照。单行小区,随机区组排列,3次重复。结果表明,在干旱季节,所有生草处理区都显著改善了根际土壤水分和温度状况,而百喜草和白三叶草生草区土壤丛枝菌根真菌孢子数和柑桔根系菌根侵染率显著高于清耕区和其它生草区。表明在干旱季节,百喜草和白三叶草生草栽培促进了果园土壤丛枝菌根真菌的生长和柑桔根系菌根的形成,从而促进了柑桔根系对水分和磷素营养的吸收利用。试验结果表明果园管理中宜选择菌根侵染率高的草种如百喜草、白三叶草在柑桔园进行生草栽培,促进柑桔根系菌根形成,改善植株生理代谢,提高果品质量。     

Temperature Before Cold Acclimation Affects Cold Tolerance and Photoacclimation in Timothy (Phleum pratense L.), Perennial Ryegrass (Lolium perenne L.) and Red Clover (Trifolium pratense L.)

The expected temperature rise in late summer/early autumn can change the conditions for acclimation and affect the winter survival of perennial crops. This study examined the effect of the temperature just before the onset of cold acclimation (pre‐acclimation) on freezing tolerance of timothy (Phleum pratense L.), perennial ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L.) populations (both cultivars and breeding populations) adapted to either northern or southern parts of Norway. Using phytotron experiments, we studied whether increasing pre‐acclimation temperature delays growth cessation, affects photoacclimation and reduces freezing tolerance. Furthermore, we assessed whether these effects were related to the latitudinal adaptation of the plant material. The results showed that a rise in pre‐acclimation temperature decreased both cold acclimation capacity and photoacclimation in these species. This affected the freezing tolerance, which was reduced significantly more in northern‐adapted population of timothy and perennial ryegrass compared with southern‐adapted populations. Red clover was less affected by temperature changes than the grasses.     

Genetic differences in root mass of Lolium perenne varieties under field conditions

Although grasses have dense rooting systems, nutrient uptake and productivity can be increased, and N-leaching reduced, if rooting is further improved. The variation in root mass of 16 varieties of Lolium perenne was studied under field conditions in two experiments on sandy soil in The Netherlands. The chosen varieties differed in genetic and aboveground characteristics such as ploidy, productivity and grass cover. Root dry matter (RDM) was measured in the 0–8, 8–16 and 16–24 cm soil layers. In summary, we found that RDM of perennial ryegrass differed significantly between varieties under field conditions. These differences were not linked to grass yield, which indicates that it is possible to select perennial ryegrass varieties that combine high aboveground productivity with high RDM. In the first experiment, which was managed by cutting, diploid varieties had higher RDM than tetraploid varieties. Grand mean RDM in the second experiment, which was managed by cutting as well as grazing, was lower than in the first experiment. In this experiment, total RDM was not influenced by ploidy but by grass cover type: high grass cover types had higher RDM. Differences in management between the two experiments possibly explain the differences in RDM and in the influence of chosen characteristics on RDM. Considering challenges in the areas of climate change, water availability, pollution and soil degradation, grass varieties with improved root systems could significantly contribute to a more efficient use of nutrients and water, erosion control, soil improvement and carbon sequestration.     

Improved seed yield in perennial ryegrass (Lolium perenne L.) from two generations of phenotypic selection

Two generations of recurrent phenotypic selection for seed yield per plant under controlled pollination were carried out to combine improved seed yield with improved forage grass performance in perennial ryegrass (Lolium perenne L.). Selected and unselected varieties (AberDartand AberElan respectively) and control varieties were grown for seed in pots in a glasshouse experiment and in two field plot experiments over 5 harvest years. Seed yield components and seed yield were measured. Significant improvements in seed yield of the selected AberDart over the unselected AberElan were observed both in individual plants grown in the glasshouse and in field plots. Detailed observations of the individual components of seed yield showed that the increased seed yield of AberDart can be attributed to a higher proportion of ovules forming seeds (% seedset), greater seed number per tiller and more reproductive tillers per plant. This improvement in seed yield of AberDart was also observed when it was grown in field plots with AberElan, experimental selection lines and commercial varieties. AberDart produced more seeds per tiller than the other commercial varieties and selection lines studied. The implication of this approach for the breeding of perennial ryegrass varieties that combine good agronomic performance and acceptable seed yields is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of Competition upon the Productivity of White Clover-Perennial Ryegrass Mixtures. Genetic Analysis

A diallel cross amongst four contrasting white clover varieties was used to provide genetic information on those characters which affect the productivity of white clover-perennial ryegrass mixtures when grown under a cutting-only management regime. Generally speaking those characters recorded on the clover families and in mixtures exhibited highly significant additive and non-ad dative genetic effects, though for1 sortie characters the latter could not be ascribed solely to dominance effects. For two of the clover characters, stolon and leaf number, the genetic picture was radically altered in mixtures by the effects of inter-specific competition Pseudo-genetic effects were also detected for the grass characters, bur it was suggested that the two ryegrass varieties used here were exhibiting phenotypic plasticity. As a group the four intra-varietal crosses performed significantly better than the six intra-varietal crosses for all clover and mixture characters. Only one of the inter-varietal crosses had significantly positive specific combining ability effects for most characters and that was between the two long established varieties ‘S. 184’ and ‘S. 100’. The implications of these results for the breeding of white clover varieties for use in mixtures are briefly discussed.     

Effects of water deficit and plant interaction on morphological growth parameters and yield of white clover (Trifolium repens L.) and ryegrass (Lolium perenne L.) mixtures

The effects of soil water deficit and interspecific plant interaction were studied on the dry matter (DM) yield of white clover and ryegrass and on the morphogenesis of white clover. Plants were grown either: (1) individually (no interaction); or in a mixture of equal plant numbers with either (2) just shoot interaction, or (3) both shoot+root interaction. Plants were subjected to soil water deficits corresponding to no (0 MPa), moderate (−0.5 MPa) or severe (−1.0 MPa) water deficit. Ryegrass had higher above- and below-ground DM yields than white clover. The above- and below-ground DM yield for ryegrass, and the above-ground DM yield, stolon growth and relative growth rate (RGR), and leaf appearance rate (LAR) for white clover decreased as soil water deficit increased. In shoot+root interaction at no and moderate soil water deficit levels, white clover had the highest proportion of above-ground growth in the leaf form (69%) and had, respectively, 11% and 32% more above-ground DM yield than when grown in just shoot interaction; ryegrass had, respectively, 20% and 25% more above-ground DM yield than ryegrass grown in just shoot interaction. In shoot+root interaction at severe soil water deficit, ryegrass had twice as much above-ground DM yield as white clover (3.50 g per plant versus 1.59 g per plant, respectively) and white clover had 60% less above-ground DM yield than when grown in just shoot interaction. In a soil column of restricted depth (30 cm) at no and moderate soil water deficit levels, remarkable increases in shoot biomass yield were observed for both white clover and ryegrass grown in shoot+root interaction. The increased shoot biomass yield of ryegrass can be attributed to benefits from white clover's N fixing ability, whereas the causes for increased white clover biomass yield need to be studied further. However, at severe soil water deficit, ryegrass had a competitive advantage over white clover when grown in shoot+root interaction. This was due to the larger root system of ryegrass and its ability to control transpirational losses more efficiently, thus prolonging its growth period compared with white clover.     

First in vivo assessment of feeding value of Festulolium hybrids derived from Festuca arundinacea var. glaucescens and selection for palatability

This paper reports on the first results of feeding value experiments, assessed with sheep, of hybrids between tetraploid Italian ryegrass (Lolium multiflorum, 2n = 4×= 28) and a progenitor of tall fescue, Festuca arundinacea var. glaucescens (2n = 4×= 28). Three hybrid populations resulting from either high, low or no selection for palatability were compared with a variety of Italian ryegrass as control and two varieties of the cultivated hexaploid (2n = 6×= 42) tall fescue, one of which had been selected for high palatability. On average, the hybrid populations were found to be as palatable as the improved tall fescue with voluntary intake (VI), in vivo digestibility of organic matter (DOM), and net energy expressed in fodder units for milk, similar to the best palatable tall fescue and to Italian ryegrass. However, selection for improved palatability among hybrids did not result in any further improvement of other traits, except VI in the hybrid selected for high palatability which significantly exceeded VI of Italian ryegrass. In conclusion, intergeneric hybridization between L. multiflorum and F. arundinacea var. glaucescens led to an immediate increase of feeding value compared with selection for palatability in tall fescue. However, to improve feeding value of hybrids further, similar selection for high palatability appeared questionable and possibly detrimental for other agronomic traits because of complicated inheritance in tetraploid L. multiflorum×F. glaucescens hybrids.     

Breeding forage grasses for organic conditions

Herbage yield trials are necessary to test if candidate varieties are well suited for organic conditions. In order to elucidate a particular suitability for organic conditions, we run such trials in parallel under both organic and conventional conditions. Here, we report on second and third year results of the sowings 2004 and 2005. These trials are part of a targeted breeding programme for organic conditions. Irregular colonisation of pure grass plots with adventitious plants, in particular white clover, was recognized as a major constraint to the quality of the results obtained under organic conditions. The coefficients of variance in dry matter yield almost doubled when compared to conventional trials, and significant differences in annual yield among varieties were rare. However, when herbage yield was corrected for the estimated fraction of adventitious plant colonization at each cut, the number of instances with statistically significant differences for annual yield among varieties increased more than fourfold. Dry matter yields under organic and conventional conditions were significantly and positively correlated. However, analysis of variance showed a significant culture type by variety interaction for annual dry matter yield in 12 out of 24 trials. When diploid and tetraploid varieties of the same Lolium species were tested in one common trial, only tetraploid varieties were identified as being particularly well suited for organic conditions, while in these trials, the great majority of apparently poorly suited varieties were diploid. This suggests that breeding tetraploid Lolium varieties is promising when aiming at a favourable response to organic agriculture.     

The Relationship Between Progeny Seed Yield in Drilled Plots and Maternal Spaced-Plant Traits in Perennial Ryegrass (Lolium perenne L.)

Seed production in perennial ryegrass, Lolium perenne L., is low. Early selection for high seed yield carried out in spaced plants would be valuable for breeders, but only if this potential is also expressed in derived progenies sown later in drilled plots. Therefore, spaced-plant traits assessed on clonal ramets of 31 genotypes in each of two perennial ryegrass varieties in four environments were related to seed production characteristics in drilled plots of open-pollinated progenies of these plants. Significant differences were found among these half-sib families for seed yield, thousand-grain weight, spring performance and earliness. The number of spikelets per ear in the maternal plants was negatively correlated with the seed yield of the progenies, explaining 17 % of the variation for seed yield in the cv. ‘Barenza’ and 14 % in the cv. ‘Wendy’. Multiple regression analyses revealed that no combinations of plant traits consistently explained a major portion of the variation for seed yield of the progenies. The results indicate that in these varieties, spaced-plant data are of limited value in predicting seed production. Direct selection for seed yield in drills of progenies in later stages of the breeding programme remains the best method for obtaining varieties with sufficient seed production.     

Establishment, Development and Yield of Forage Legumes and Grasses as Cover Crops in Grain Corn in Eastern Canada

Interseeded cover crops can minimize soil erosion, increase organic matter and nutrient levels and the yield of subsequent crops. However, their performance is very sensitive to local conditions. Field experiments were conducted at two Quebec locations in 1993 and 1994 in order to evaluate the potential use of forage legumes and grasses as interseeds in corn in eastern Canada. Twelve forage species were evaluated. Fall rye ( Secale cereal L.), hairy vetch ( Vicia villosa Roth), a mixture of red clover ( Trifolium pratense L.) and ryegrass ( Lolium multiflorum Lam), a mixture of white clover ( Trifolium repens L.) and ryegrass, subterranean clover ( Trifolium subterraneum L.), yellow sweet clover ( Melilotus officinalis Lam.), black medic ( Medicago lupulina L.), Persian clover ( Trifolium resupinatum L.), strawberry clover ( Trifolium fragiferum L.), crimson clover ( Trifolium incarnatum L.), annual alfalfa ( Medicago saliva L.) and berseem clover ( Trifolium alexandrinum L.) were seeded at two planting dates (10 and 20 days after corn emergence). The control treatments were: hand weeding, chemical weeding and non-weeded. Early seeded forages established better and had higher biomass accumulation than the late seeded ones. In the presence of larger weed populations, the interseeded forages did not develop well due to competition with the weeds. At Macdonald crimson clover provided good soil cover while Persian clover, fall rye and alfalfa provided relatively little cover. Strawberry clover and hairy vetch did not provide early ground cover due to their late development. Forage mixtures of red or white clover and rye grass established well and achieved high populations at the end of the growing season. Fall rye provided good early ground cover but senesced by the middle of the season. The better establishment and early germination of crimson clover caused a 19% reduction in corn grain yield in 1993. In 1994 none of the cover crops caused a reduction in corn yield.     

紫茎泽兰对两种牧草发芽的化感克异作用

研究了紫茎泽兰地上部分、根系及根际土壤不同浓度提取液对白三叶和多花黑麦草发芽的影响。研究结果表明：紫茎泽兰对白三叶和黑麦草种子萌芽存在化感克异现象，并且随浓度的增加，影响越大；相同条件下，对白三叶的影响强于多花黑麦草；低浓度对白三叶败育的影响较大，但对多花黑麦草几乎没有影响；紫茎泽兰根际土壤对两种牧草种子萌芽无明显的化感克异作用。     

Differentiation in competitive ability and cold tolerance between diploid and tetraploid cultivars in Lolium perenne

In a diploid grass, perennial ryegrass (Lolium perenne L.), many autotetraploid cultivars have been released and widely used in many cool temperate countries. In this study, competitive ability and cold tolerance, which seem to be important factors in determining geographical distribution and persistency of this species, were compared between six diploid and five autotetraploid cultivars. The tetraploid cultivars had significantly higher competitive ability and lower cold tolerance than the diploid cultivars. Furthermore, there was no overlap in the two traits between them. These results suggest that chromosome doubling has a larger effect on competitive ability and cold tolerance than does the genetic difference between the populations within a single ploidy level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Cross compatibility between diploid and tetraploid perennial ryegrass (Lolium perenne L.)

Summary A number of crosses were made between diploid and tetraploid Lolium perenne plants in order to determine the degree of cross compatibility between the two different ploidy levels. The range of hybridization undertaken involved diploidxdiploid, and tetraploid x tetraploid control crossings, diploid x tetraploid crosses, tetraploid x diploid crosses and mixed pollinations. The seed set, the germination capacity of resultant hybrid seeds, and the chromosome constitution of derived seedlings was determined. In addition attempts were made to culture 12 day-old hybrid embryos from the diploid x tetraploid and reciprocal crosses.The crossing results obtained indicated no barrier to fertilization between diploids and tetraploids, but the irregular and poor development of the seed accompanied by much reduced germination, indicated unsatisfactory endosperm establishment of large numbers of triploids, as confirmed by the result of culturing embryos dissected from 12-day old seeds.In preliminary studies undertaken to determine the extent to which diploid and tetraploid ryegrass varieties intercross when grown in close proximity for seed production, Griffiths and Pegler (1966) observed a very low incidence of triploids amongst the progenies of diploid plants exposed to the pollen of tetraploid plants and also amongst the progenies of tetraploid material exposed to the pollen of diploid plants.In these and subsequent studies it was noted that only a very small proportion of the so-called fully formed seeds derived from diploid x tetraploid crosses did actually germinate. When, in 1964, propagules of clones of S.24 perennial ryegrass, well separated from one another, were placed in drills of the tetraploid perennial ryegrass variety Reveille, the proportion of florets which formed caryopses, and of caryopses which germinated was as follows (Table 1).The data (Table 1) clearly indicate that a considerable proportion of the S.24 florets had been fertilized by 2n pollen and had formed caryopses, but most of these had proved to be defective. As noted in the previous studies, the frequency of triploid seedlings was low, thus suggesting incompatibility between the n and 2n gametes for the production of viable zygotes.Of the total progenies classed as tetraploids in the early seedling stage, 80% proved to be ryegrass x tall fescue F₁ hybrids. These arose as a result of free crossing with     

Winter cover crop: the effects of grass–clover mixture proportion and biomass management on maize and the apparent residual N in the soil

The advantages and disadvantages of varying mixture proportion of crimson clover (Trifolium incarnatum L.) and Italian ryegrass (Lolium multiflorum Lam.), used as winter cover crops, and cover crop biomass management before maize sowing (Zea mays L.) were studied in a series of field experiments in Eastern Slovenia. Pure stands and mixtures of cover crops on the main plots were split into different cover crop biomass management subplots: whole cover crop biomass ploughed down before maize sowing, aboveground cover crop biomass removed before ploughing and sowing, or aboveground cover crop biomass removed before sowing directly into chemically killed residues.Cover crop and cover crop biomass management affected the N content of the whole aboveground and of grain maize yields, and the differences between actual and critical N concentrations in the whole aboveground maize yield. The whole aboveground and grain maize dry matter yields, and the apparent remaining N in the soil after maize harvesting, showed significant interaction responses to cover crop × management, indicating positive and negative effects. Crimson clover in pure stand provided high, and pure Italian ryegrass provided low maize dry matter yields and N content in the yields in all the observed methods of biomass management. However, within individual management, mixtures containing high proportions of crimson clover sustained maize yields and N contents similar to those produced by pure crimson clover. Considering the expected ecological advantages of the mixtures, the results thereby support their use.