Plant Pathology Commons^™

Estimation Of Digestibility Of Legume Forages By Means Of Morphological Parameters, W Kuhbauch

IGC Proceedings (1977-2023)

Forage quality is normally evaluated by time-consuming and costly laboratory analyses. It appears promising to use mor­phological parameters to evaluate forage quality in alfalfa and red clover. During progressive growth of white clover, red clover, and alfalfa, the leaf and stem portion was separated to determine the fiber fraction according to the Van Soest method and to

estimate digestibility by the procedure of Tilley and Terry. Stem : leaf ratio and stand height as a measure of stem length were used as morphological parameters. Leaves of the three legumes vary only slightly in concentration of cell-wall material and in digestibility …

Effect Of Sheep And Cattle Grazing On A Mixed Pasture Of Perennial Ryegrass, Kikuyu, And White Clover, G J. Goold

IGC Proceedings (1977-2023)

Mixed pastlkes of perennial ryegrass (Lolium perenne L. ), kikuyugrass (Pennisetum clandestinum Hochst. ), and white clover (Trifolium repens L.) are commonly found within warm-zone areas of New Zealand but are frequently disliked because of prob­lems associated with kikuyugrass dominance. A grazing experiment was conducted to provide basic information on the response of such swards to grazing by cattle and sheep. The pastures were rotationally grazed with young sheep or cattle at two stocking levels each year from 1970 to 1975, with stocking rates adjusted twice yearly according to seasonal pasture growth. The pastures grazed by cattle …

Dynamics Of Herbage Growth And Senescence In A Mixed-Species Temperate Sward Continuously Grazed By Sheep, J S. Bircham, J Hodgson

IGC Proceedings (1977-2023)

Four perennial ryegrass (Lolium perenne L.)-Poa annua L.-white clover (Trifolium repens L.) swards with herbage mass rang­ing from 500 to 1,700 kg organic matter (OM)/ha were established and maintained in as near a steady state as possible by con­tinuous but variahle stocking with sheep in order to study the influence of herbage mass on rates of herbage growth (G), senescence (S), and net production (NP), and on species balance. Estimates ofG, S, and NP were derived from measurements on individual grass tillers and clover stolon growth sites. The mean contributions to total G were 54, 20, and 4 ( ± …

Animal Production With Controlled And Fixed Stocking And Managed Stocking Rates, R E. Blaser, J T. Johnson, F Mcclaughterty, J P. Fontenot, R C. Hammes Jr, H T. Bryant, D D. Wolf, D A. Mays

IGC Proceedings (1977-2023)

Grazing experiments were conducted to implement and improve animal-grazing-management systems. The primary objec­tives were (experiment 1) to investigate animal production with fixed and controlled stocking and (experiment 2) to study animal production and canopy characteristics with three managed stocking rates. Live-weight gains/head for the grazing season were similar for fixed and controlled stocking; during a summer period, gains/head were higher for controlled stocking. Gains/head were not associated with available herbage. The canopies with fixed stocking had 28% to 82% more forage than those with controlled stocking, the former being high in dead tissues and stems. Controlled stocking gave 61 % …

Feeding Value Of The Legume Component In Pasture And Silage, K.F M. Reed, P T. Kenny

IGC Proceedings (1977-2023)

Grazing experiments were conducted to examine the feeding value of various pastures for grazing sheep and, in some cases, as silage. Recently, the use of legumes for improving the growth of weaned lambs during the dry summer and early autumn was in­vestigated at Hamilton, Victoria. Studies in Australia showed that the fleeceweights of weaner sheep grazed on eight pasture mixtures of varying grass species increased as the amount of clover in the pasture increased (r -0.88 • *). In a separate study, young sheep grew faster on lucerne· grass pasture than on grass-subtenanean dover pasture. Most recently, live-weight gains of …

Effects Of Treading And The Return Of Excreta On A Perennial Ryegrass - White Clover Sward Defoliated By Continuously Grazing Sheep, M L. Currl, R J. Wilkins

IGC Proceedings (1977-2023)

Grazing sheep may affect the association between grass and clover in a mixed sward by defoliation, treading, and the circula­tion of nitrogen (N) via excreta. Our objective was to examine the effect of treading and excreta on a perennial ryegrass (Lolium perenne)-white clover (Trifolium repens)sward defoliated by sheep at high and low stocking rates. Established swards of perennial ryegrass and white clover were continuously stocked from May to October with yearling wether sheep at 25 and';5() head/ha. Sward production and species composition were measured inside graze-through cages that allowed defoliation without treading and excreta return, and …

Photosynthesis And Dry-Matter Distribution In Altitudinal Ecotypes Of White Clover, J Noseberger, F Machler, B C. Boller

IGC Proceedings (1977-2023)

Productivity of white clover (Trifolium repens L.) is limited by plant characteristics that prevent efficient use of environmen­tal inputs. In the temperate zone, low temperature often limits growth. Comparisons of ecotypes originating from sites with cool or warm climatic conditions (low or high altitudes) can show, when plants are grown in a common environment, the degree of adaptation of processes related to net photosynthesis and the distribution of dry matter. Our objectives were to determine the photosynthetic responses to temperature in relation to the thermal regime during growth and the effects of temperature and daylength on partitioning of dry matter …

Mutual Influence Of Temperate Legumes And Grasses Grown In Association At Different Nitrogen Levels, E Meister, J Lehmann

IGC Proceedings (1977-2023)

In grass/legume associations white clover (Trifolium repens), red clover (Trifolium pratense) and alfalfa (Medicago sativa) contribute significantly to the nutritive value of such mixtures. Compared to Italian ryegrass (Lolium italicum), perennial ryegrass (Lolium perenne) and orchard grass (Dactylis glomerata ), the legumes have an inherently higher content of protein, magnesium and calcium. In addition they indirectly help to improve the quality (protein and mineral content) of the companion grass, presumably over a nitrogen transfer from the legume to the grass partner: On the other hand, the chemical composition of these …

Effect Of Early Season Nitrogen On Nitrogen Fixation In A Ryegrass/ White Clover Pasture, P M. Murphy, P. Roger Ball

IGC Proceedings (1977-2023)

The effect of rate and time of nitrogen fertilizer application on nitrogen fixation by white clover (Trifolium repens) in a ryegrass sward was studied under field conditions in two consecutive years. Very different weather conditions prevailed over the two years resulting in contrasting seasonal patterns of nitrogen fixation. In 1983 only 30% of the total annual fixation rate was achieved by rate June and this pattern was reversed in 1984. Nitrogen fertilizer affected nitrogen fixation more than clover growth in 1983 but in 1984 a combination of fertilizer and drought reduced both clover growth and nitrogen fixation. At the highest …

Competition Effects On Nitrogen Fixation And Mineral N Uptake In Trifolium Repens L.- Lolium Perenne L. Associations, C P. West, K W. Steele, E A. Halligan

IGC Proceedings (1977-2023)

Improved While clover (Trifolium re pens L.) cul ti vars can potentially increase the input of nitrogen (N) from symbiotic fixation into clover-grass pastures and maintain elevated N2 fixation rates in the presence of nitrogenous fertilizers. The objective of this study was to determine the effects of interspecific competition on N2 fixation and mineral N uptake in white cover-perennial ryegrass (Lolium perenne L.) associations with either a medium-small ('Grasslands Huia') or large leaved ('G18') cultivar. The clover and grass were grown in a controlled environment room in pots that were partitioned to allow either no interspecific competition for shoots and …

Allelopathic Effects Of Tall Fescue On Germination And Seedling Growth Of White Clover Genotypes, G A. Rederson

IGC Proceedings (1977-2023)

Tall fescue (Festuca arundinacea Schreb.) and white clover (Trifolium repens L.) are commonly grown together in pastures of the southeastern USA. Allelopathy of tall fescue may reduce white clover germination and growth during establishment of the legume. The objective of this study was to determine if white clover genotypes differ in germination and initial growth in extracts of tall fescue leaves. Agar containing leaf extracts from tall fescue was used to test the germination and root growth of forty white clover genotypes. Significant differences were found between the genotypes for percent germination and root length score. Root length score …

Rates Of Destruction Of Growing Points Of Pasture Legumes By Grazing Cattle, R J. Clements

IGC Proceedings (1977-2023)

Twining tropical pasture legumes such as Siratro ( Macropti­lium atropurpureum) are unable to persist under sustained heavy grazing, whereas prost��ate legumes such as white clover (Trifolium repens) persist well. The reasons for this are not fully understood. Survival of individual Siratro plants is reduced by heavy grazing (Jones and Bunch, 1988). The destruction of growing points of erect legumes during grazing may reduce growth and weaken the plants. The effects of graz­ing pressure on the demography of growing points and on turn­over of plant tissue have been studied at this Laboratory since 1984. Some results are reviewed briefly …

The Role Of Goats In New Zealand Hill Country Farming, D A. Clark, M G. Lambert

IGC Proceedings (1977-2023)

The predominant domesticated ruminants in New Zealand are sheep and cattle. However in the last decade other animal species have been incorporated into farming systems, particu­larly goats which have increased from 10 thousand to 1 million over that time. The motives for this change have primarily been economic ones, in an attempt by farmers to increase income and reduce costs. Goats provide direct financial returns to hill farmers through sale of fibre (mohair, cashgora, cashmere) and meat. In many instances however, the motivation has been one of reduction of weed control costs. Aspects of weed control, pasture response and grazing …

Prospects For Legume-Based Dairying In Cool Temperate Conditions, M Ryan

IGC Proceedings (1977-2023)

There is increasing interest in exploiting legume-based pastures in the temperate zones of NW Europe-their value for lamb and beef production being recently documented (Stewart, 1984; Davies and Munro, 1988). Legume-based intensive dairying is currently not prevalent north of - 49 NL but quota restrictions leading to fewer cows may create conditions favourable to legumes within dairying. This paper describes the results of experimentation comparing N and legume-based dairying in cool temperate conditions and assesses future pros­pects.

Performance Of Trifolium Repens Genotypes Under Grazing In New Zealand Hill Pasture, J.F L. Charlton, D R. Woodfield, J R. Caradus

IGC Proceedings (1977-2023)

A large area of New Zealand's hill country has been developed into pasture during the past 60 years by removal of scrub vegetation, aerial application of superphosphate fertiliser and aerial oversowing of pasture seeds in mixture. The key legume used was white clover (Trifolium repens L.), either as the cultivar Grasslands Huia, or as uncertified seed. Grasslands Tahora white clover was released in 1984, selected from material collected from moist hill pastures (Williams et al., 1983). Farmers sowing white clover into such pastures now have a choice of using Tahora (specifically bred for moist hill pasture, close-grazed by sheep), …

Legume Breeding Strategy For Increased Nitrogen Fixation In New Zealand Temperate Pastures, J R. Crush

IGC Proceedings (1977-2023)

The energy level actually achieved at any site in grassland is governed by the mass flow of nitrogen (N) through the biota (O'Connor, 1967). As nitrogen limits pasture production, at all stages of pasture development, the aim of pasture management is to maintain the maximum amount of effective nitrogen in the system (Jackman, 1971). Prospects for increasing symbiotic N fixation in temperate grasslands have been reviewed (Ball and Crush, 1985). Of two strategies, growing more legume or reduc­ing the legumes ability to use mineral nitrogen, the former was favoured. This was because mineral nitrogen is thought to be important, in …

Etude Des Deux De La Nutrition Azotee Du Trefle Blanc (Trifolium Repens L.): Activite De La Nitrogenase Et De La Nitrate Reductase, D Schontz, C Robin, A Guckert

IGC Proceedings (1977-2023)

L'importance des deux voies de la nutrition azotee (assimila­tion de l'azote combine et moleculaire) du trefle blanc n'a ete etudiee qu'en terme de bilans 15N (Haystead et Lowe, 1977). L'objet de cette etude est de suivre la cinetique des activites de la nitrate reductase et de la nitrogenase au cours du cycle de developpement en presence de differentes concentrations en nitrates.

Effets Di Nitrate Sur La Croissance Et La Fixation D’Azote Chez Le Trefle Blanc (Trifolium Repens L.): Importance De La Souche De Rhizobium, D Schontz, C Robin, D Laurentie, A Guckert

IGC Proceedings (1977-2023)

Des apports d'azote combine sur des associations graminees­trefle blanc provoquent souvent un desequilibre favorable a la graminee. Cet effet peut etre attribue a une moindre competiti­vite de la legumineuse pour prelever l'azote combine (difference d'exploration du sol par le systeme racinaire) mais aussi a une moindre action de l'azote sur la croissance, du fait de !'inhibi­tion de la fixation. L'objet de cette etude est de tester !'influence de la souche de Rhizobium sur la sensibilite de la fixation d'azote et sur !es consequences de cette sensibilite sur la croissance du trefle en presence de differents niveaux de nitrates.

Fixation De L’Azote Chez Le Trèfle Blanc (Trifolium Repens L.) Interactions Entre Le Deficit Hydrique Et La Fertilization Potassique, A Guckert, L Shamsun Noor, C Robin, D Schontz

IGC Proceedings (1977-2023)

Le role du potassium au niveau de l'etat hydrique des vege­taux et notamment des processus d'osmoregulation est bien connu (Mengel, 1984). Dans ce contexte nous avons cherche a determiner l'effet d'un apport d'engrais potassique sur le com­portement du trefle blanc en situation de deficit hydrique. Nos observations ont porte sur ]'evolution du potentiel de base, de l'activite photosynthetique et de la fixation d'azote.

Derivation And Testing Of Nutrient Norms For White Clover, Marta J. Rodreiguez

IGC Proceedings (1977-2023)

Foliar analysis has been practiced widely to diagnose the nutrient status of crops in order to give fertilizer recommenda­tions. The changing nature of plant tissue mineral concentra­tions imposes limitations on the use of foliar analysis for diag­nostic purposes. In this way, sampling of particular plant parts at particular stages of development is required to assess the nutrient status of crop and forage plants. The Diagnosis and Recommendations Integrated System (DRIS) was developed by Beaufils (1973), based on a holistic experimental approach, as a means of coping with the problems derived of the dynamic nature of foliar composition. Three concepts are …

Deferred Grazing During Summer Increases White Clover Content In New Zealand Dairy Pastures, S L. Harris, C D. Waugh, R J. Mccabe, V T. Van Vught

IGC Proceedings (1977-2023)

NZ dairy pastures under rotational grazing (grazing interval 25 to 30 days) are often grazed down to low residual herbage masses (<1000 kg DM/ha) over summer resulting in white clover death. Deferred grazing, the practice of holding over pasture in situ over summer, was shown to promote survival of clover growing points and increase clover seedling density in mixed perennial ryegrass / white clover dairy pastures. As a result clover content (% of total dry matter (DM)) was increased, particularly in the first year of the trial when summer climatic conditions were unfavourable for clover growth. Additional pasture cover built up in plots deferred for 100 days from late November to March resulted in significantly higher soil moistures and lower soil surface temperatures so providing more favourable growing conditions for clover. Deferred grazing also resulted in small increases in total herbage accumulation but had little effect on ryegrass tiller density.

Pasture Species Effects On Animal Performance, T J. Fraser, S=J S. Rowarth, T L. Knight

IGC Proceedings (1977-2023)

Increasing concerns about food quality have resulted in investigations into the effects of different forage species on animal production and carcass quality. Pure species plots of high-endophyte ryegrass (Lolium perenne L.), white clover (Trifolium repens L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.) or lotus (Lotus corniculatus L.) were established and lambs grazed the species for 120 days during summer. Pasture species influenced growth rate, hot carcass weight, GR, wool growth, faecal egg counts, adult nematodes at slaughter, and sheep meat odour and flavour. Lambs grazing white clover, lotus or chicory outperformed those grazing …

Evaluation Of Grass Species In Pure Cultures And In Mixture With White Clover, M Zimkova

IGC Proceedings (1977-2023)

Four cultivars of three grass species and five grass/white clover mixtures were evaluated in field small-plot trials on persistence and dry matter production (DM) in 1993-95. Of pure grass species the meadow fescue (Festuca pratensis) was the most productive though its persistence has declined in the third year (3.2 points in 1995). Both perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) mixtures have been well performing with 1.3 - 2.4 points for persistence and with yields of 6.4 - 9.56 t DM/ha-1.

Impact Of A Pastoral Fallow On The Morphology And Growth Of White Clover (Trifolium Repens L.) In New Zealand Hill Pasture, Z N. Nie, I Valentine, D J. Barker, A D. Mackay, J Hodgson

IGC Proceedings (1977-2023)

Lifting the content and improving the distribution of perennial legumes such as white clover (Trifolium repens L.) of hill pastures in New Zealand is a major objective of a pasture improvement programme. This paper reports on the ecology of white clover over a 2 year post-fallow period. The fallow was a 7 month period without defoliation over spring-summer-autumn. The stolon length and weight of white clover increased from year 1 (94/95) to year 2 (95/ 96) post-fallowing (P<0.1 and 0.05, respectively), while the average internode length declined (P<0.05). However, the white clover growth rate was not significantly increased in the two measurement years. Fallowing significantly increased grass growth rate (P<0.05) in the two years post-fallowing. The grasses seemed to have an immediate response post-fallowing, while the response of white clover was slower and cumulative.

Pasture Species For Grazing-Based Dairy Production Under Irrigated In The Intermountain West, J W. Macadam, R E. Whitesides, M B. Winger, S Buffler

IGC Proceedings (1977-2023)

Forage trials were established in response to producer interest in grazing-based dairy production. The quantity and seasonal distribution of yield of tall fescue (Festuca arundinacea Schreb.), orchardgrass (Dactylis glomerata L.), white clover (Trifolium repens var. giganteum L.), birdsfoot trefoil (Lotus corniculatus L.), and cicer milkvetch (Astragalus cicer L.) harvested three times were similar, with about half the production occurring in June. Legume quality was higher in June, and quality for all species was highest in late summer. Yields of perennial ryegrass (Lolium perenne L.), meadow bromegrass (Bromus riparius Rehm.) and Kentucky bluegrass (Poa pratensis …

White Clover Versus Nitrogen Fertilizer 2. Sheep Production, J.P J. Erens, K B. Miller, R J. Lucas, J.G. H. White, H S. Easton

IGC Proceedings (1977-2023)

Animal production on pasture systems provided with either fertiliser or biological nitrogen was compared. A grazing experiment was sown at AgResearch Gore (46°07’ S; 168°54’ E) in October, 1989. Four ryegrass/white clover paddocks were compared to four ryegrass paddocks, with the latter receiving 270 kg nitrogen/ha/year. Each paddock of 0.5 ha was subdivided for rotational grazing at 20 ewes/ ha. In comparison to the ryegrass pastures, mixed pastures produced 22% more herbage and were subsequently 22% higher stocked, lamb liveweight gains were 12% higher during lactation and 42% higher after weaning resulting in earlier sale at higher carcass weights. Ewe …

Frequent Grazing By Sheep Reduced Caucasian Clover Cover And Rhizome Mass In Ryegrass Pasture, R J. Lucas, A.J E. Moorhead, W W. Nichol, P Jarvis

IGC Proceedings (1977-2023)

The responses of hexaploid Caucasian clover (Trifolium ambiguum) to four contrasting grazing regimes were compared with white clover (T. repens ) in a high endophyte hybrid ryegrass pasture on a fertile lowland site. After two years, frequent grazing reduced Caucasian clover cover to 10% compared with 25.5% in infrequently grazed treatments (mean spelling time 25 days). Similarly, Caucasian clover rhizome plus root dry weight was reduced by frequent grazing (78 g DM/m2 sampled to 100 mm depth compared with 322 g DM/m2). White clover was encouraged by frequent defoliation (21% cover) in contrast to Caucasian clover. Ryegrass tiller …

The Nature Of Competition Between Forage Herbs, Perennial Ryegrass, And White Clover Under Organic Farming Conditions, A P. Umrani, D Younie, P R. English

IGC Proceedings (1977-2023)

Chicory and ribwort were sown alone or with perennial ryegrass (PRG), PRG/white clover (WC) or WC at three seed rates (1, 5 and 20 kg/ha) in fields or in the glasshouse in the north-east of Scotland under organic farming conditions during 1995-96. PRG showed strong negative effects on root and shoot development of the herbs, but it increased total herbage production. WC had no marked effect on herb establishment when it was sown without PRG. Density dependent competition in herbs for different seed rates were higher during early establishment when plant count was high. Competition between companion species was higher …

Potential Of A Novel White Clover/ Cereal Bi-Cropping System For Whole Crop Forage Production, N Koefoed, R O. Clements, J Burke, G Donaldson, G Purvis

IGC Proceedings (1977-2023)

A novel low input system for growing cereals, so far mainly winter wheat (Triticum aestivum L), in close association with white clover (Trifolium repens L), is being developed currently, co-operatively by five research stations in northern Europe. An established sward of pure white clover is defoliated in the autumn and winter wheat drilled into it using a rotary type direct drill. After silage or grain harvest of the cereal/clover mixture the clover regrowth may add to the productivity of the system until defoliation and drilling-in of the next cereal crop takes place. With the system described dry matter …

Indicators Of Pathogen Potential Of Pasture Soils, R A. Skipp, R N. Watson, G C.M Latch

IGC Proceedings (1977-2023)

A simple pot test was used to indicate the combined effects of several pathogens common in pasture soils (plant parasitic nematodes and pathogenic fungi e.g. Pythium spp.) by comparing the dry weight yields of clover seedlings grown in untreated soil with those from soil treated in a microwave oven. Response to microwave treatment, expressed as a "Soil Pathogenicity Index", was greater with soil from old pasture or from areas in 2 year old pasture plots showing poor regrowth after grazing of white clover (Trifolium repens L) or Caucasian clover (T. ambiguum Bieb.), than from soil from new pasture or …