Lolium perenne

About: Lolium perenne is a research topic. Over the lifetime, 4782 publications have been published within this topic receiving 107337 citations. The topic is also known as: Perennial Ryegrass, English ryegrass.

Occupation of biological space during seedling establishment

Abstract: gains access to resources necessary for its further growth and development. The term 'biological space' is used to cover this complex of resources. Such a simplification assumes that the requirements of individuals within a species are essentially similar. The object of this paper is to show the importance of the position of an individual in the overall ranking of emergence times, and its spatial separation from neighbours, in enabling it to occupy space to the exclusion of its neighbours. Most information on the performance of an individual within a population has come from work with mixed populations and this literature warrants consideration. A number of studies have been made on the temporal and spatial components of seedling interference, but the interaction of the two, interference in the dynamic context, has received less attention. The relative times at which different species are introduced into a mixture has been shown by a number of authors to produce dramatic changes in the outcome of interference between the components. When Sagar (1959) sowed S23 Lolium perenne and Plantago lanceolata simultaneously, Lolium contributed 80 % of the total plant dry weight at harvest. If Lolium were introduced 3 weeks before Plantago, the proportion contributed by Lolium rose to 90 %, but, sown 3 weeks after Plantago, Lolium contributed only 6.4 % of the total dry weight. A similar result was reported by Harper (1961) using two Bromus species. When B. rigidus and B. madritensis were sown simultaneously, the former contributed over 75 % of the final dry weight of the mixture. If the introduction of B. rigidus were delayed for 3 weeks, then the contribution by this species dropped to approximately 13 % of the total dry weight. Williams (1962) has repeated this effect in an agronomic context. He found that Chenopodium album reduced the yield of barley by 20 0 when the two were sown at the same time, but delaying barley sowing by 7 weeks allowed Chenopodium to reduce the yield of the barley by 45 %. The same effect with one species was shown by Black & Wilkinson (1963) using subterranean clover. They delayed planting alternate seeds within a grid pattern by 0, 2, 4 and 8 days, thus considerably increasing the range of emergence times within swards. By recording the final yield of each individual, they showed that a 5-day delay in the emergence of an individual reduced its final weight by 50 %, and a delay of 8 or 9 days, by at least 75 %. These differences could not be accounted for solely by differences in growing times between emergence and harvest. As early as 1938, Weaver & Clements described how an advantage gained by an individual over its neighbours was likely to be maintained or accentuated during subsequent

Supplementation of Acacia mearnsii tannins decreases methanogenesis and urinary nitrogen in forage-fed sheep

Abstract: The objective of this experiment was to assess the effects of a partial replacement of ryegrass (Lolium perenne) by red clover (Trifolium pratense) or alfalfa (Medicago sativa) supplemented with 0 or 41 g Acacia mearnsii extract (containing 0.615 g/g condensed tannins)/kg dietary dry matter on nitrogen turnover and methane release by sheep, using the respiration chamber technique. Across all variables, there was no significant interaction between basal diet and tannin supplementation. The partial replacement of the grass by the legumes remained without effect on the amounts of nitrogen excreted through faeces or urine. Nitrogen and energy utilisation was lower (P < 0.05) with ryegrass-alfalfa than with ryegrass alone, and methane release (kJ/MJ gross energy intake) was higher (P < 0.05) with ryegrass-red clover than with ryegrass alone. Tannin supplementation decreased (P < 0.05) ruminal ammonia concentration and urinary nitrogen excretion without affecting body nitrogen and energy retention, and reduced (P < 0.001) methane release by 13% on average. The results suggest that supplemented Acacia mearnsii tannins can be useful in mitigating methane and potential gaseous nitrogen emissions, whereas a replacement of grass by legumes obviously shows no advantage in this respect.

Increased concentration of water-soluble carbohydrate in perennial ryegrass (Lolium perenne L.) : milk production from late lactation dairy cows

Abstract: Eight multiparous Holstein‐Friesian dairy cows in late lactation were used to investigate the potential of using perennial ryegrass with a high concentration of watersoluble carbohydrate (WSC) to increase the efficiency of milk production. After a pretreatment period on a common pasture, the cows were each given ad libitum access to one of two varieties of zero-grazed grass continuously for 3 weeks. Treatments were: high sugar (HS), an experimental perennial ryegrass variety bred to contain high concentrations of WSC; or control, a standard variety of perennial ryegrass (cv. AberElan) containing typical concentrations of WSC. The two grass varieties were matched in terms of heading date. All animals also received 4 kg day ‐1 standard dairy concentrate. Grass dry matter (DM) intake was not significantly different between treatments (11AE6 vs. 10AE7 kg DM day ‐1 ; s.e.d. 0AE95 for HS and control diets respectively), although DM digestibility was higher on the HS diet (0AE71 vs. 0AE64 g g ‐1 DM; s.e.d. 0AE23; P <0 AE01) leading to higher digestible DM intakes for that diet. Milk yield from animals offered the HS diet was higher (15AE3 vs. 12AE6 kg day ‐1 ; s.e.d. 0AE87; P <0 AE05) and, although milk constituent concentrations were unaffected by treatment, milk protein yields were significantly increased on the HS diet. The partitioning of feed N was significantly affected by diet, with more N from the HS diet being used for milk production (0AE30 vs. 0AE23 g milk N g ‐1 feed N; s.e.d. 0AE012; P <0 AE01) and less being excreted in urine (0AE25 vs. 0AE35; s.e.d. 0AE020; P <0 AE01). In a separate experiment, using the same grasses harvested earlier in the season, the fractional rate of DM degradation, measured by in situ and gas production techniques, was higher for the HS grass than for the control. It is concluded that increased digestible DM intakes of the HS grass led to increased milk yields, whereas increased efficiency of utilization of the HS grass in the rumen resulted in the more efficient use of feed N for milk production and reduced N excretion.

Diversity of arbuscular mycorrhizal fungi colonising roots of the grass species Agrostis capillaris and Lolium perenne in a field experiment

Abstract: Analysis of arbuscular mycorrhizal (AM) fungal diversity through morphological characters of spores and intraradicular hyphae has suggested previously that preferential associations occur between plants and AM fungi. A field experiment was established to investigate whether AM fungal diversity is affected by different host plants in upland grasslands. Indigenous vegetation from plots in an unimproved pasture was replaced with monocultures of either Agrostis capillaris or Lolium perenne. Modification of the diversity of AM fungi in these plots was evaluated by analysis of partial sequences in the large subunit (LSU) ribosomal RNA (rDNA) genes. General primers for AM fungi were designed for the PCR amplification of partial sequences using DNA extracted from root tissues of A. capillaris and L. perenne. PCR products were used to construct LSU rDNA libraries. Sequencing of randomly selected clones indicated that plant roots were colonised by AM fungi belonging to the genera Glomus, Acaulospora and Scutellospora. There was a difference in the diversity of AM fungi colonising roots of A. capillaris and L. perenne that was confirmed by PCR using primers specific for each sequence group. These molecular data suggest the existence of a selection pressure of plants on AM fungal communities.

Diet preference of sheep: effects of recent diet, physiological state and species abundance

Abstract: The preference of sheep for two temperate grassland species, ryegrass and white clover, was tested by releasing flocks (of three ewes) onto swards (0.25 ha) that contained adjacent monocultures of grass and clover, and observing their intake behaviour over 6 days. The test paddocks contained either 20, 50, or 80% clover by ground area to distinguish partial preference from indifference. To test whether recent diet affected preference, separate groups of dry (non-pregnant, non-lactating) ewes grazed prior to testing on one of three diet «back-grounds»: an all-grass sward, an all-clover sward, or a 50:50 grass/clover sward by area. To consider the effects of physiological state on preference, a further group of lactating ewes, also from a 50:50 grass/clover «background», were tested