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Persistence Of Phalaris Aquatica L. In Response To Grazing, R A. Culvenor Sep 2024

Persistence Of Phalaris Aquatica L. In Response To Grazing, R A. Culvenor

IGC Proceedings (1993-2023)

Cultivars of phalaris (Plialaris aquatica L.) bred in Australia for seedling vigour and winter activity are reported to be less persistent in response to heavy_ grazing than the original introduction, cv. Australian. In an experiment comparing the morphological characters of cultivars, Australian was shown to possess a morphology well adapted to grazing. In contrast, the bred cultivars formed more erect pastures with low basal area, more prone to invasion by annual grasses and retaining less leaf area after grazing. In a second experiment, sheep displayed preference during July for grazing the winter-active cultivar Sirosa over cv. Australian, probably because …


Effect Of Management On Leaf Growth And Senescence Of Three Contrasting Grass Species, B M. Butler, J Hodgson Sep 2024

Effect Of Management On Leaf Growth And Senescence Of Three Contrasting Grass Species, B M. Butler, J Hodgson

IGC Proceedings (1993-2023)

The innuence of continuous grazing management on leaf extension, leaf senescence and tiller density of 3 grass species with contrasting tillering rates, tiller size and growth habit was examined. Perennial ryegrass (Lolium perenne L. cv. Grasslands Nui), tall fescue (Festuca arundinacea Schreb, cv. Grasslands Roa) and Yorkshire fog (Holc,,s la11allls L. cv. Massey Bnsyn) were maintained in as near a steady state as possible at sward heights of 3-10 cm. The balance between leaf extension and senescence, and tiller density resulted in net extension per unit area being generally greatest at sward heights of- 5.5 cm in Yorkshire fog and …


Whole-Stand Carbon Gains And Nitrogen Distribution In Herbaceous Stands, M.J A. Werger, T Hirose Sep 2024

Whole-Stand Carbon Gains And Nitrogen Distribution In Herbaceous Stands, M.J A. Werger, T Hirose

IGC Proceedings (1993-2023)

We studied canopy structure and leaf nitrogen distribution in open and dense stands of tall dicot and monocot herbs and compared the results with simulated canopy performance under uniform and optimised leaf nitrogen distributions. Dense stands showed leaf nitrogen distributions that greatly differed from those of uniform distribution but did not completely match optimum distribution. In dense stands this led to strongly enhanced potential whole canopy carbon gains, while in open stands the leaf nitrogen distribution was not very important in this respect. Dense stands of monocots kept more leaf nitrogen in the lower parts of their canopies than is …


Advances In Genetic Transformation Of Plants, Thomas K. Hodges, Keerti S. Rathore, Jianying Peng Sep 2024

Advances In Genetic Transformation Of Plants, Thomas K. Hodges, Keerti S. Rathore, Jianying Peng

IGC Proceedings (1993-2023)

Many plant species, including both dicots and monocots, can now be genetically engineered with individual genes isolated from any source. Methods for delivery of foreign DNA into plant cells or protoplasts utilise Agrobacterium tumefaciens (and A. gazogenes), micro­injection, polyethylene glycol, electroporation and particle guns. Advantages and disadvantages of each system are discussed. At present, all systems involve i11 vitra cell or tissue culture lo some extent, and this is the most difficult and variable aspect of plant genetic engineering. In addition, all systems suffer from random insertions of the foreign DNA into the plant genome. This requires Southern blot screening …


Applications Of Random Amplified Polymorphic Dna (Rapd) Markers In Plant Biology, Gail M. Timmerman, John A. Mccalum Sep 2024

Applications Of Random Amplified Polymorphic Dna (Rapd) Markers In Plant Biology, Gail M. Timmerman, John A. Mccalum

IGC Proceedings (1993-2023)

RAPDs are a new class of molecular marker based on PCR amplification of genomic DNA using random sequence primers. Their value for studying plant genomes has been clearly demonstrated in the short lime they have been in use. Uses of RAPD markers include genome mapping, lagging of genes, studying genetic diversity, identifying cultivars and analysing parentage. RAPDs should prove to be as applicable to the study of animal genomes ns they have for plant genomes, It is important that researchers using or planning to use this type of molecular marker be aware of two possible drawbacks of RAPDs. Since RAPDs …


A Strategy For Cloning Apomixis-Associated Cdna Markers From Buffelgrass, D L. Gustine, R T. Sherwood, D A. Hulce Sep 2024

A Strategy For Cloning Apomixis-Associated Cdna Markers From Buffelgrass, D L. Gustine, R T. Sherwood, D A. Hulce

IGC Proceedings (1993-2023)

A strategy to select apomixis-associated cDNA sequences was partially tested in buffelgrass (Pennisetum ciliare (L.) Link, = Cenclrrns ciliaris L.). The dominant A gene allele which confers apomixis would likely be expressed as mRNA only in reproductive tissue undergoing megasporogenesis. Sexual lines lack the apomixis allele. Poly A+ mRNA was isolated from meiotic florets of obligately apomictic line Higgins and sexual line B-11-7 and cloned into lwnbda gl23A. cDNA sequences associated with the npomictic phenotype were enriched by subtracting sequences common lo both plants as follows. Insert DNA sequences of sexual and apomictic cDNAs were released with Notl and …


Genetic Transformation Of Dactylis Glomerata By Microprojectile Bombardment, B V. Conger, D D. Songstand, J K. Mcdaniel, J Bond Sep 2024

Genetic Transformation Of Dactylis Glomerata By Microprojectile Bombardment, B V. Conger, D D. Songstand, J K. Mcdaniel, J Bond

IGC Proceedings (1993-2023)

Dactylis glomerata L., cv, Embryogen-P, has been previously genetically transformed by direct uptake of DNA by suspension culture-derived protoplasts. The objective of the present experiments was 10 use this genotype to obtain transformation by microprojec1ile bombardment. Bmbryogenic suspension cultures and plated basal leaf segments were bombarded with DNA coated tungsten particles propelled by two different helium pressure discharge apparatuses. The DNA plasmids contained genes for chlorosulfuron resistance, hygromycin resistance and !i-glucuronidase (GUS). Transient expiession for GUS was obtained on both suspension cultures and leaf segments. A stable event for GUS and 16 plants which rooted well on 2.5 mg/I chlorosulfuron …


Somatic Embryogensis And Plant Regeneration From Immature Inflorescences Of Hyparrhenia Hirta (L.) Stapf, R Hatipoglu, A Gland, C U. Hesemann, T Tukel Sep 2024

Somatic Embryogensis And Plant Regeneration From Immature Inflorescences Of Hyparrhenia Hirta (L.) Stapf, R Hatipoglu, A Gland, C U. Hesemann, T Tukel

IGC Proceedings (1993-2023)

The study was conducted to determine an efficient system for in vitro culture and Hyparrhenia hirta, The effects of 2 different auxins (2,4-D and dicamba) at 3 concentrations (4.5 µM, 22,6 µM and 45,2 µM) and 2 ecotypes with different chromosome numbers (2n= 36 and 2n • 54) on callus induction and plantlet regeneration from immature inflorescences of Hyparrhenia hirta were investigated. Inflorescence segments of 5 mm length from greenhouse-grown plants were cultured on a modified Linsmaier and Skoog medium supplemented with 30 g/1 agar, Large differences In frequency of callus induction and callus weight were observed among lhe different …


Somatic Embryogensis And Plant Regeneration From Long-Term Suspension Culture Of Digitaria Decumbens, Yu-Kuei Cheng Sep 2024

Somatic Embryogensis And Plant Regeneration From Long-Term Suspension Culture Of Digitaria Decumbens, Yu-Kuei Cheng

IGC Proceedings (1993-2023)

The optimum condition for embryogenic callus formation and plant regeneration from immature inflorescences of Digltarla decumbens was MS medium supplemented with O,S mg/I 2,4-D, 2.0 mg/) kinetin and 0,591, NaCl. For long-term subcultures, pieces of embryogenic callus were cultured on MS liquid medium supplemented with 1-2 mg/1 2,4-D, 0.591, NaCl, 5% coconut milk, SOO mg/I casein hydrolase and O.S mg/I 6-benzylaminopurlne, and were subcultured every 4-S days. Bmbryogenic suspension cultures were maintained for more than 1 year. More than 5000 plants may be produced from an explant within 6 months. Bmbryoids from suspension cultures showed a bipolar organisation.


Transformation Of White Clover With A Gene Encoding A White Clover Mosaic Virus Coat Protein, Brigitta Dudas, R L.S Forster, C J. Van Dolleweerd, D.W R. White Sep 2024

Transformation Of White Clover With A Gene Encoding A White Clover Mosaic Virus Coat Protein, Brigitta Dudas, R L.S Forster, C J. Van Dolleweerd, D.W R. White

IGC Proceedings (1993-2023)

Genes encoding the white clover mosaic virus (WClMV) coat protein . have been introduced into white clover (Trifolimn repens L.) using Agrobacterium tumefaciens mediated T-DNA transfer. Integration of the coat protein gene in regenerated callus has been confirmed hy Southern blotting of polymerase chain reaction (PCR) amplification products generated using specific oligonucleotide primers. A polyclonal antibody, raised against purified WCIMV coal protein, recognised a polypeptide of c. 25 kDa after SOS-PAGE and Western blotting. The recogilised polypeptide co-migrates with the purified coat protein. Using ELISA, levels of coat protein accumulation in transgenic callus have been determined. The scope for …


Embryo Rescue And Somatic Hybridisation For The Production Of Interspecific Hybrids In The Genus Medicago, S Arcioni, F Damiani, M Piccirilli, F Pupilli Sep 2024

Embryo Rescue And Somatic Hybridisation For The Production Of Interspecific Hybrids In The Genus Medicago, S Arcioni, F Damiani, M Piccirilli, F Pupilli

IGC Proceedings (1993-2023)

T• broaden the germplasm sources available for the genetic improvement of alfalfa, new interspecific hybrids between Medlcago saliva L. and other Medicago species (M. coemlea, M. arborea and M. rugosa) hove been obtained. To • overcome lncompalibility barriers existing between alfalfa and the wild species, ovule-embryo culture and somatic hybridisation were used. Viable plants were obt11incd through the utilisation of both techniques Md their hybrid nature was demonstrated by analysis of morphological traits, by cylological investigations and by electrophorelic profiles of esterascs and peroxidases. Hybrids were fertile and In the fulure their backcross to alfalfa should allow the useful tr11i,s …


Use Of Molecular Markers In Alfalfa For Construction Of A Genetic Map And Studying Genetic Rearrangements In Non-Sexually Derived Hybrids, F Damiani, F Pupilli, M Piccirilli, S Arcioni Sep 2024

Use Of Molecular Markers In Alfalfa For Construction Of A Genetic Map And Studying Genetic Rearrangements In Non-Sexually Derived Hybrids, F Damiani, F Pupilli, M Piccirilli, S Arcioni

IGC Proceedings (1993-2023)

Two genomic libraries have been constructed from Medicago saliva DNA reslfictcd with both Pstl and EcoRT. The libraries have been screened and compared for the presence of highly repeated DNA sequences. Restriction fragment length polymorphism among 3 varieties of M. saliva (Rangelander, Adriana, CADL) and 3 species of the genus Medicago (M. coerulea, M. falcata, M. arborea) has been investigated using a large number of probe-enzyme combinations .. Four-and 6-base cutter restriction enzymes have been used. DNA electrophoresis has been performed with· 2 substrates (agarose and polyacrylamide) in order to detect polymorphism at a higher range of fragment lengths. About …


Use Of Allozyme Genetic Markers To Follow The Establishment Of White Clover Oversown Into Hill Country, K D. Adam, M E. Wedderburn, L A. Greaves Sep 2024

Use Of Allozyme Genetic Markers To Follow The Establishment Of White Clover Oversown Into Hill Country, K D. Adam, M E. Wedderburn, L A. Greaves

IGC Proceedings (1993-2023)

Allozyme marker loci Gpi-3,4 and Pgm-3,4 were used to monitor establishment of plants of the white clover (Trifolium repens L., cv. Grasslands Huia) oversown into 3 steep, north-facing hill country pastures. Comparisons of genotype frequencies in samples of the unimproved (resident) populations, the oversown populations 18 months after oversowing and Huia, provided information about changes in the genetic composition of the white clover populations after oversowing. In each case, oversowing brought about significant changes in allele frequencies but the estimated proportions of plants of cuhivar Huia were variable at 24.2%, 92.4% and 100%, indicating that establishment rates can vary not …


Tissue Culture Of Sainfoin, Nakashima Hiroshi, Yang Zhuomeng Sep 2024

Tissue Culture Of Sainfoin, Nakashima Hiroshi, Yang Zhuomeng

IGC Proceedings (1993-2023)

The effecls of 1-napthaleneacetic acid (NAA) and 6-benzylamino purine (BAP) on callus induction, callus proliferation and plant regeneration were examined ip sainfojn (011ob1ycl1is viciifo/ia Scop.) from differen! ex plant. Then the effects of indole-3-butyric acid (IBA) on root formation from differentiated shoot from calli were examined. The combinations of 1-10 µM ofNAA an4 BAP were better for sainfoin culture. For callus induction, there was no significant difference among 3 explants, but Chere were interactions between explant and media. For plant regeneration, hypocotyl and root are 􀄊ter explants than cotyledon. The effects of NAA and BAP showed less effective on callus …


Use Of Allozyme Genetic Markers To Follow The Establishment Of White Clover Oversown Into Hill Country Pastures, K D. Adam, M E. Wedderburn, L A. Greaves Sep 2024

Use Of Allozyme Genetic Markers To Follow The Establishment Of White Clover Oversown Into Hill Country Pastures, K D. Adam, M E. Wedderburn, L A. Greaves

IGC Proceedings (1993-2023)

Allozyme marker loci Gpi-3,4 and Pgm-3,4 were used to monitor establishment of plants of the white clover (Trifolum repens L., cv. Grasslands Huia) oversown into 3 steep, north-facing hill country pastures. Comparisons of genotype frequencies in samples of the unimproved (resident) populations, the oversown populations 18 months after oversowing and Huia, provided information about changes in the genetic composition of the white clover populations after oversowing. In each case, oversowing brought about significant changes in allele frequencies but the estimated proportions of plants of cuhivar Huia were variable at 24.2%, 92.4% and 100%, indicating that establishment rates can vary …


Application Of The Somaclone Method In Fertility Restoration Of The Partially Sterile Hybrid Of Agropyron Repens X Bromus Inermis: Callus Initiation And Plant Regeneration, L E. Heszky, J Janovsky, G Gyulai, E Kiss, L T. Hangyel Sep 2024

Application Of The Somaclone Method In Fertility Restoration Of The Partially Sterile Hybrid Of Agropyron Repens X Bromus Inermis: Callus Initiation And Plant Regeneration, L E. Heszky, J Janovsky, G Gyulai, E Kiss, L T. Hangyel

IGC Proceedings (1993-2023)

. Callus initiation and plant regeneration from the new intergeneric hybrid of Agropyron repens L., Beauv, x Bromus inermis.1 Leyss. cv. Nanus (Agromus) was carried out. For callus initiation, the inflorescence primordia were incubated on an optimised nutritive medium designated medium-F, supplemented with 2,4-dichlorophenoxyacetic acid (0.5 mg/ I). Within 21 days of plating, embryogenic callus with globular structures were developed, From the 21st day of culture, one-step plant regeneration occurred from callus without subculture. Non-regenerative calli were subcultured to medium-F supplemented with different cytokinins. The cytological analysis of the calli showed wide genetic:il variability in chromosome number with …


Dairying Farming In New Zealand, Bryan Guy Sep 2024

Dairying Farming In New Zealand, Bryan Guy

IGC Proceedings (1993-2023)

Dairy farming in New Zealand is primarily an export industry based almost entirely on the use of perennial ryegrass and while clover. A low cost dairy farming system has been developed and it is this system which enables the New Zealand dairy farmer to survive on returns from the international marketplace. Milk marketing in New Zealand is controlled by a single producer organisation, the New Zealand Dairy Board, which also provides breeding services lo some 14 700 dairy farmers. The industry aims to maximise the net income of dairy farmers. Emphasis is on efficient production and is often measured on …


Sheep And Beef Farming On The West Coast Of The North Island Of New Zealand, R A. Neeley, T G. Parminter Sep 2024

Sheep And Beef Farming On The West Coast Of The North Island Of New Zealand, R A. Neeley, T G. Parminter

IGC Proceedings (1993-2023)

Over 40% of New Zealand's occupied land area is devoted to hill country farming. The forms are typically owned, managed and ·worked by a single family with some help from seasonal labour. The properly owned by L.D. and R.A. Neeley is a typical example of the type of hill country farms found on the west coast of the North Island. It has an effective area of 520 ha and carries 5000 stock units, 30% of which are cattle. The sheep policy is to finish 60-100% of lambs produced from an improved Romney breed flock (with a 90-100% lambing rate). Friesian …


Policy Developments And Trade Prospects For Grassland-Based Products, Graeme H. Tie, Jayantha P. Kottege, Brian S. Fisher Sep 2024

Policy Developments And Trade Prospects For Grassland-Based Products, Graeme H. Tie, Jayantha P. Kottege, Brian S. Fisher

IGC Proceedings (1993-2023)

The economic outlook for grassland-based products over the next decade will be influenced by a range of factors. Important among these will be the outcome of the agricultural negotiations in the Uruguay Round of the General Agreement on Tariffs and Trade. Failure to achieve satisfactory agricultural reform in the Uruguay Round could result in an acceleration in the trend toward the formation of regional trading arrangements. This could, in turn, lead to increased fragmentation of the international trading system. Such fragmentation reduces the global economic gains available from trade which stem from specialisation and the associated exercise of comparative advantage. …


European Grassland Farming: Future Prospects, David R. Harvey, Caroline Saunders Sep 2024

European Grassland Farming: Future Prospects, David R. Harvey, Caroline Saunders

IGC Proceedings (1993-2023)

The paper reviews recent policy reforms and current pressures in Europe, including the CAP reforms, GATT considerations, the potential for European and CIS integration, and the environmental pressures on policy. The possible consequences of these reforms are then considered, illustrated by estimates of European grassland product market conditions in the event of multilateral free trade in form products. Finally, the implications of these trends for farming practices are considered, with special reference to the UK and European Community. In spite of rather glacial progress towards trade liberalisation, Che conclusions are: i) that future· strategic planning at both national and farm …


A Traditional Exporter's Perspective Of Trade Reforms, N R. Mitchell Sep 2024

A Traditional Exporter's Perspective Of Trade Reforms, N R. Mitchell

IGC Proceedings (1993-2023)

The agriculture and trade policies which governments commonly have pursued over the last three decades, particularly governments in the large developed countries, have had a major impact on world patterns of production and trade in livestock and livestock products. This has been especially so for milk and dairy products where government involvement in markets has been most pervasive. One effect has been that the comparative advantages derived from the production of livestock products based on pasture feeding of animals \lave been suppressed or overridden. Reform of the international trading system for agricultural products now being developed in the GATT, and …


Impact Of Changing Trade Opportunities On Livestock Production In Developing Countries, J K. Camoens Sep 2024

Impact Of Changing Trade Opportunities On Livestock Production In Developing Countries, J K. Camoens

IGC Proceedings (1993-2023)

For the lesser developed countries (LDCs) and advanced countries (ACs), the paper identifies the determinants of "free" trade, analyses protectionism, examines the global trade picture with respect lo "free" trade, relates trade to production and the structure of demand, and finally predicts the impact of trade reforms. The analysis concludes that: (i) trade policies per se do not impact in any significant manner on domestic production or imports in the LDCs since world trade constitutes a small fraction of production; (ii) demand, and hence supply, of animal products are determined primarily by GNP, income distribution and price; (iii) grassland farming …


Development Of Grain-Saving, High Efficiency Pasture Animal Industry, Han Gui Qing Sep 2024

Development Of Grain-Saving, High Efficiency Pasture Animal Industry, Han Gui Qing

IGC Proceedings (1993-2023)

Grain-saving, high efficiency pasture-sustained (GSHEPS) animal industry, with its final purpose of profitable industry, is forage-orientated. This is a new fonn of operation based on advanced feeding management.


Seasonal Changes In Forage Regrowth Yield And Quality Of Three Old World Bluestems, Larry M. White Sep 2024

Seasonal Changes In Forage Regrowth Yield And Quality Of Three Old World Bluestems, Larry M. White

IGC Proceedings (1993-2023)

Little information is available on differences in regrowth yield and quality among Old World bluestems (Bothriochloa spp.). Harvesting was staged such that 4-week regrowth of Caucasian (B. caucasica), cv. WW-Iron Master (D, ischaemum var. i.,ischaemum) and cv, Super Cauc (D. caucasica) was harvested each week from early May through mid-September to determine forage yield, ill vitro dry matter digestibility (IVDMD) and crude protein content of leaves and stems. Forage yield peaked in late June with WW-Iron Master, Caucasian, and Super Cauc producing 1280, 11S0 and 930 kg/ho/4 weeks of leaves and S00 200 and …


Herbage Production And Quality Of Rs2, A Quackgrass (Elytrigia Repens [L.]Neski.) X Bluebunch Wheatgrass (Pseudoroegneria Spicata [Pursh.] Love) Hybrid, M R. Haferkamp, D C. Adams, E E. Grings, P O. Currie Sep 2024

Herbage Production And Quality Of Rs2, A Quackgrass (Elytrigia Repens [L.]Neski.) X Bluebunch Wheatgrass (Pseudoroegneria Spicata [Pursh.] Love) Hybrid, M R. Haferkamp, D C. Adams, E E. Grings, P O. Currie

IGC Proceedings (1993-2023)

Fertiliser and mowing effects on herbage quality and yield of the RS2 hybrid were studied. Plants were fertilised with 0, 112 or 224 kg Nlha in spring 1988 and 1989, or with 112+112kg N/ha split in spring-summer, Plants were unmowed or mowed to a SO mm stubble height on selected dates in 1988 and 1989. Maximum standing crops (SC) of unmowed plants averaged 3000 kg/ha in 1988 and 5600 kg/ha in 1989; SC were increased 1000 kg/ha by fertilisation in 1989. Crude protein (CP) exceeded 120 g/kg in unmowed herbage in 1988 and decreased from 200 g/kg in May to …


Utilization Of Tall Fescue In Pure Stand, In Association With White Clover And In Complex Mixtures, S Badoux Sep 2024

Utilization Of Tall Fescue In Pure Stand, In Association With White Clover And In Complex Mixtures, S Badoux

IGC Proceedings (1993-2023)

Tall fescue (Festuca arundinacea Schreb.) was cultivated in pure stand, in association with white clover (Trifolium repens L.) and in various complex grass-legume mixtures. Forage yield and quality were always higher in associations with white clover than in tall fescue pure stands. However, under dry conditions, the balance between the two components was difficult to maintain. In more complex mixtures cocksfoot and tall fescue tended to become dominant and to produce a forage of lower quality. In mixtures of long duration, we replaced meadow fescue by tall fescue. Total yield over 3 years was improved; the digestibility of …


Use Of Plant Height For Determining The Nutritive Value, Yield And The Optimal Use Span Of Lucerne, Lother Schmidt Sep 2024

Use Of Plant Height For Determining The Nutritive Value, Yield And The Optimal Use Span Of Lucerne, Lother Schmidt

IGC Proceedings (1993-2023)

Determining the ·cutting date is important for high yield, good forage quality and longevity of lucerne (Medicago media Pers.) stands. Most recommendations for the optimal use date are based on the development ,stage. The results of research conducted over 9 years show that forage quality and the dry matter (DM) yield of luccrne, at the same, developmental stage, vary considerably, depending on weather conditions during the growth period. A better criterion is the plant height of lucerne. There was a highly significant correlation between plant height and the content of crude fibre, crude protein and DM. We recommend the …


Lamb And Steer Production From Continuously Grazed Alfalfa, Jerry D. Volesky, Daniel P. Mowrey Sep 2024

Lamb And Steer Production From Continuously Grazed Alfalfa, Jerry D. Volesky, Daniel P. Mowrey

IGC Proceedings (1993-2023)

Little is known about livestock production from alfalfa (Medicago saliva L,) under continuous grazing. Objectives were to determine lamb and steer performance, production and leaf-stem selection on continuously grazed alfalfa. Lambs and steers separately grazed 3 replicate pastures from late April through mid-August, 1991. Initial stocking densities were relatively heavy to utilise rapid spring growth after which livestock numbers were reduced to maintain alfalfa with a 20-cm stubble height. Season-long live-weight gains for the lambs and steers were 0.15 and 0.94 kg/day. Total production for lambs and steers was 557 and 529 kg/ha, Lamb diets generally contained a higher …


Impact Of Intermittent Clipping On Productivity, Forage Quality And Legume Persistence Of Reclaimed Mine Soils, M Collins, H B. Rice, R Turley, W O. Thom Sep 2024

Impact Of Intermittent Clipping On Productivity, Forage Quality And Legume Persistence Of Reclaimed Mine Soils, M Collins, H B. Rice, R Turley, W O. Thom

IGC Proceedings (1993-2023)

The materials used as plant growth media during surface mine· reclamation are frequently low in available N, P and K and are drought­prone. Legumes are included in reclamation seeding mixtures . because of their symbiotic N2-fixation ability but competition may prevent establishment or reduce persistence. A field study was conducted to test the hypothesis that intermittent clipping of these sites would reduce grass competition and thereby maintain legume stands. In 1990 and· 1991, 4 clipping treatments were imposed, providing intervals of 2, 4; and 6 weeks between harvests. Clipping at the 2- or 4-week intervals gave equal yields that were …


Sward Height In Grazing Management: Vertical Profiles In Forage Quality, J E. Johnston, A Singh, E A. Clark Sep 2024

Sward Height In Grazing Management: Vertical Profiles In Forage Quality, J E. Johnston, A Singh, E A. Clark

IGC Proceedings (1993-2023)

Vertical and temporal trends in herbage yield and quality were assessed in a study sown in 1989 near Elora, Ontario. In a replicated field trial with 0.1 ha paddocks, Hereford heifers rotationally grazed 2 swards to each of 2 residual grazing heights, namely, SO and 100 mm, with a requisite 200-2S0 mm entry height. Profiles in yield and in in vitro organic mailer digestibility (IVOMD) were developed from 6, 1500 cm2 quadrats per paddock, which were subjected to vertically stratified clipping, using sheep shears with a vacuum attachment. In 1990, obliging entry. at 200-2S0 mm stabilised herbage organic matter on …