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Articles 61 - 90 of 58709

Full-Text Articles in Physical Sciences and Mathematics

Interactions Of Rotational And Continuous Grazing With Stocking Rate On Warm And Cool-Season Pastures, David I. Bransby Sep 2024

Interactions Of Rotational And Continuous Grazing With Stocking Rate On Warm And Cool-Season Pastures, David I. Bransby

IGC Proceedings (1993-2023)

With more intense commercialisation of electric fencing many production and economic advantages have been claimed for rotational grazing compared with continuous grazing. However, very little research data are available from the south-eastern USA to verify these claims, Therefore, the objective of this study was to evaluate animal performance under conditions of continuous and IO-paddock rotational grazing on cool- and warm-season pastures commonly used in this region. Three 2-year grazing experiments were conducted, one each on a mixed rye-annual ryegrass (Secale cereale-Lolium multiflorum) pasture, Coastal bermudagrass ( Cynodon hybrid) and Pensacola bahiagrass (Paspalum notatum). In each experiment continuous …


Integrating Pasture Technology Research With Farm Management, R T. Cowan, T M. Davison, K F. Lowe, G K. Reason, G D. Chopping Sep 2024

Integrating Pasture Technology Research With Farm Management, R T. Cowan, T M. Davison, K F. Lowe, G K. Reason, G D. Chopping

IGC Proceedings (1993-2023)

An applied research programme which involved farmers in a continuum of trials measuring pasture, soil and milk responses to the application of nitrogen fertiliser to tropical grasses is described. Pasture responses were consistent across farms, grass species and, within limits, rainfall zones and soil types. Soil pH declined by 0.03 lo 0.2 units each year. Additional milk production ranged from 4 to 14 I/kg nitrogen, the response being greater at lower levels of application. Results from farm and research station experiments were consistent. The high adoption rate, reaching 68% in 6 years, was ' attributed to the integration of farm …


Hay Supplementation And Stocking Rate Effects On Live Weight Gain Of Steers Grazing Rye And Ryegrass, Susan E. Sladden, David I. Bransby Sep 2024

Hay Supplementation And Stocking Rate Effects On Live Weight Gain Of Steers Grazing Rye And Ryegrass, Susan E. Sladden, David I. Bransby

IGC Proceedings (1993-2023)

The objective of this study was to evaluate continuous ad lib. supplementation of hay as a means of compensating for the uneven growth distribution of rye (Secale cereale) and ryegrass pastures (Lolium multiflorum) grazed by steers in the south-eastern USA. Pastures were continuously grazed by 230 to 270 kg steers at stocking rates of 2.5, 3.1, 4.1 and 4.9 head/ha with and without hay supplementation for 2 grazing seasons. On average, average daily live-weight gain (ADO) at the highest stocking rate (4.9 steers/ha) was 0.47 kg higher (P<0.01) when hay supplement was provided. Although not significant, in both years ADO tended to be higher for h_ay supplementation even at low stocking rates .


Improved Pasture Species, Fertilizer And Pasture Use To Increase The Productivity Of Wool Sheep In South-Western Victoria, G R. Saul, D Jowett, T Morgan, P Noble, D Borg Sep 2024

Improved Pasture Species, Fertilizer And Pasture Use To Increase The Productivity Of Wool Sheep In South-Western Victoria, G R. Saul, D Jowett, T Morgan, P Noble, D Borg

IGC Proceedings (1993-2023)

Pastures were upgraded by sowing perennial grasses and subterranean clover (Trifolium subterranum) and applying fertiliser to paddocks on S farms in the wool sheep region of south-western Victoria. Upgraded pastures were stocked at higher rates to ensure utilisation of feed grown. In the third year after sowing, wool production was increased by 56% (35 v. SS kg/ha), and ewe live weights by 4% (49.4 v. 51.4 kg) from upgraded pastures compared with untreated pastures. The results demonstrate the considerable potential to increase output from sheep farms in the region by upgrading pastures. Poor persistence of sown perennial grasses may …


System Research: Preliminary Results From A Farmlet Comparison Between A Biological And Conventional Sheep And Beef System, A D. Mackay, D I. Gray, I M. Brookes, P J. Budding, B Devantier Sep 2024

System Research: Preliminary Results From A Farmlet Comparison Between A Biological And Conventional Sheep And Beef System, A D. Mackay, D I. Gray, I M. Brookes, P J. Budding, B Devantier

IGC Proceedings (1993-2023)

Initial findings of a farm let study comparing biological (agrochemical­ free) and conventional sheep and beef production are presented and discussed. Little difference was found in sheep production between the two systems in 1991-92, despite large differences in the level of internal parasitism, particularly in young sheep. In contrast! growth rates of rising 1 year steers and heifers on the conventional unit were superior to those of the biological farmlet throughout spring and summer of the first year. While a reduction in the use of anthelmintic drench would have little impact on the productivity of sheep systems, the productivity of …


A Management System For The Planning, Implementation, And Monitoring And Evaluation Of Farmlet Trials, D I. Gray, A D. Mackay, P J. Budding, I M. Brookes Sep 2024

A Management System For The Planning, Implementation, And Monitoring And Evaluation Of Farmlet Trials, D I. Gray, A D. Mackay, P J. Budding, I M. Brookes

IGC Proceedings (1993-2023)

A management system used to operate the farmlet component of a farm· systems research programme investigating biological sheep and beef production is described and the advantages and disadvantages of this approach are discussed,


Economics Of Milk Production From Perennial Ryegrass Cultivars With Different Seasonal Growth Patterns, I M. Brookes, A F. Mcrae, D I. Gray, N Cameron Sep 2024

Economics Of Milk Production From Perennial Ryegrass Cultivars With Different Seasonal Growth Patterns, I M. Brookes, A F. Mcrae, D I. Gray, N Cameron

IGC Proceedings (1993-2023)

Cutting trials at 4 sites throughout New Zealand over 2 years with perennial ryegrass (Lolium perenne L) cultivars showed that Bmbassy (B) produeed similar annual dry matter (DM) yields to Supernui (S) and Yatsyn (Y). However, B grew 10% more DM in January-August, but 5% less DM in September-December. The economic value of these diffecent patterns of growth for milk production was assessed using a computer model. The model constrained pasture covers within specified limits by removing excess feed for conservation and adding additional feed as supplements during periods of deficit. Stocking rates needed to maintain the system in equilibrium …


Effect Of Sward Surgace Height On Herbage Intake, Grazing Behavior And Productivity Of Ewes Lambing In June (Winter) Or August (Spring), S T. Morris, W J. Parker, H T. Blair, S N. Mccutcheon Sep 2024

Effect Of Sward Surgace Height On Herbage Intake, Grazing Behavior And Productivity Of Ewes Lambing In June (Winter) Or August (Spring), S T. Morris, W J. Parker, H T. Blair, S N. Mccutcheon

IGC Proceedings (1993-2023)

Herbage organic mailer intakes (OMI) were measured, using chromic oxide capsules, during the last 4 weeks of pregnancy in ewes due to lamb in June (winter) or August (spring). OM! (averaged across lambing date groups) were 1.4±0.1, 1.8±0.1, 1.8±0.1 and 2.0±0.1 kg OM/ewe/day (mcan±s.e.m. P<0.05) in ewes maintained at sward surface heights (SSH) of 20, 40, 60 and 80 mm respectively. There were no differences in OM! between June- and August-lambing ewes from pregnancy day 122 to day 125 (Pl22-Pl25), but between Pl35 and 139 June-lambing ewes had lower OMI than August-lambing ewes (1.5±0.1 v. 1.7±0.1 kg OM/ewe/day (P<0.05)). Live-weight gain of ewes was lowest on the 20 mm sward and highest on the 80 mm sward (157±34 v. 315±31 g/day, P<0.05). SSH had no effect on lamb birth weight. Preliminary data presented here suggest that, at the same SSH, June-lambing pregnant ewes can achieve OMI similar to those of August-Jambers.


Seasonal Herbage Intake Of Once-Bred Heifers, A A. Khadem, S T. Morris, W J. Parker, R W. Purchas, S N. Mccutcheon Sep 2024

Seasonal Herbage Intake Of Once-Bred Heifers, A A. Khadem, S T. Morris, W J. Parker, R W. Purchas, S N. Mccutcheon

IGC Proceedings (1993-2023)

Once-bred heifer (ODH) beef production systems, which are new to New Zealand, involve mating heifers at 15 months of age to cnlve as 2-year-olds and then slaughtering the heifers (at less than 30 months of age) as prime beef. Never-pregnant, pregnant and lactating Hereford x Friesian heifers were used in 4 experiments. There were no significant differences between pregnant (days 260-270 of pregnancy) and never-pregnant heifers in their herbage organic matter intake (OMI), ingestive behaviour or daily live-weight gain (LWG) when a restricted pasture allowance of 7 kg DM/head/day was offered. Heifers at days 50-60 of lactation and never-pregnant heifers …


A Response Of Angora-Type Goats To Increases Of Legume And Chicory Content In Mixed Pastures, D R. Stevens, M J. Casey, G S. Baxter, K B. Miller Sep 2024

A Response Of Angora-Type Goats To Increases Of Legume And Chicory Content In Mixed Pastures, D R. Stevens, M J. Casey, G S. Baxter, K B. Miller

IGC Proceedings (1993-2023)

Live-weight gain of angora-type year-old wethcr goats in the spring and summer of 2 years was compared with the total legume and chicory content of 9 different grass, legume, chicory ( Cichorium intybus) mixtures. These pastures were grown in a cool moist temperate climate on fertile silt loam soil. The goats were held on a self• contained rotationally grazed system on each pasture type, leaving a post-grazing residual height of 10 cm. The live-weight gain of the goats responded quadratically to increasing legume and chicory content in both spring and summer. Live-weight gain was optimised when approximately 40% of …


Effects Of Increasing Stocking Rate And Feeding Maize Silage On Live-Weight Gain And Pasture Utilization By Beef Cattle In Southern Australia, W J. Wales, J B. Moran Sep 2024

Effects Of Increasing Stocking Rate And Feeding Maize Silage On Live-Weight Gain And Pasture Utilization By Beef Cattle In Southern Australia, W J. Wales, J B. Moran

IGC Proceedings (1993-2023)

Two systems of grazing management were compared in 3 trials conducted on annual or irrigated perennial pastures over different seasons in northern Victoria, Steers grazed either at low stocking rates or at high stocking rates together with maize silage feeding, The more intensely grazed steers grew faster on autumn perennial pastures but at similar rates to steers at low stocking rates on winter­spring annual and on spring perennial pastures, Higher stocking rates increased live-weight gain per ha by 90% on winter-spring annual pastures, 101% on autumn perennial pastures and 53% on spring perennial pastures. This was associated with improvements in …


Signigicance Of Grasslands In Emission And Absorption Of Greenhouse Gases, K Minami, J Goudriaan, E A. Lantinga, T Kimura Sep 2024

Signigicance Of Grasslands In Emission And Absorption Of Greenhouse Gases, K Minami, J Goudriaan, E A. Lantinga, T Kimura

IGC Proceedings (1993-2023)

Grasslands account for about 20% of lhe terrestrial CO2 fluxes of the global carbon cycle. They have a similar share in global soil organic carbon, Grasslands are likely to contribute to a global biotic carbon sequestration, reducing the rate of increase of atmospheric CO2. Methane (CH4) uptake rates and nitrous oxide (N20) emissions are given for established grassland and neighbouring forest-floor soils in Japan. Under aerobic conditions grassland and forest soils act as a sink for atmospheric CH4.The global terrestrial uptake rate for CH4 is estimated to range between 7 and 78 Tg CH4 per year. The sink strength of …


Implications For Grasslands Of The Response To Climate Change By The World Food System, Martin Parry, Cynthia Rosenzweig Sep 2024

Implications For Grasslands Of The Response To Climate Change By The World Food System, Martin Parry, Cynthia Rosenzweig

IGC Proceedings (1993-2023)

A recent and preliminary assessment of the sensitivity of the world food trade to climate change has indicated the following: Assuming {unrealistically} no adjustments in inputs, global food grains production in 2060 is estimated to be reduced by l-7% from the level that would be expected under a future without climate change. Food prices, including feedstock prices, are estimated lo be increased as a consequence, The implications of lhese changes for grassland production systems are considered. Two broad types of adjustmenls in inputs can be envisaged: firstly, on-farm responses of crop type and management and, secondly, national and international policy …


Defining Gcte Modelling Needs For Pastures And Rangelands, Bruce Campbell, Mark Stafford Smith Sep 2024

Defining Gcte Modelling Needs For Pastures And Rangelands, Bruce Campbell, Mark Stafford Smith

IGC Proceedings (1993-2023)

A short workshop was held at the Climate Change session of the XVII International Grassland Congress (JGC - New Zealand, February 1993) under the auspices of the Internntional Geosphere-B iosphere Programme (IGBP) Global Change and Terrestrial Ecosystem (GCTE) core project. The workshop was chaired by the Head of IGBP-GCTE, Dr Brian Walker, and was attended by 50 people. This report outlines discussions from the workshop and is supplemented with material from the GCTE Operational Plan and some other sources, and comments from other researchers unable to attend the workshop. Draft workplans for modelling pastures and rangelands under GCTE have been …


Genetics Of Fibre Degradation In The Rumen, Particularly In Relation To Anaerobic Fungi, And Its Modification By Recombinant Dna Technology, C G. Orpin, G Xue Sep 2024

Genetics Of Fibre Degradation In The Rumen, Particularly In Relation To Anaerobic Fungi, And Its Modification By Recombinant Dna Technology, C G. Orpin, G Xue

IGC Proceedings (1993-2023)

A number of rumen bacteria, fungi and protozoa are involved in fibre digestion in the rumen. Recombinant DNA technology bas allowed the isolation and characterisation of key genes coding for several enzymes involved in fibre degradation. The main species that have been examined are the bacteria Ruminococcus spp., Fibrobacter succinogenes and the anaerobic fungus Neocallimastix patriciarum. Genes coding for endo--1,4-glucanases and xylanase are common amongst all these organisms, but we will concentrate on recent advances in the genetics of plant fibre digestion by N. patriciarum, which contains genes coding for relatively high level activity exo- 1,4-glucanase which may …


Molecular Basis Of Legume-Rhizobium Interactions: Potentials For Improving Symbiotic Nitrogen Fixation, Adam Kondorosi, Michael Schultze, Beate Hoffmann, Csaba Koncz, Laszlo Bogre, Michele Cren, Ilona Dusha, Denes Dudits, Eva Kondorosi Sep 2024

Molecular Basis Of Legume-Rhizobium Interactions: Potentials For Improving Symbiotic Nitrogen Fixation, Adam Kondorosi, Michael Schultze, Beate Hoffmann, Csaba Koncz, Laszlo Bogre, Michele Cren, Ilona Dusha, Denes Dudits, Eva Kondorosi

IGC Proceedings (1993-2023)

The establishment of nit.rogen-fixing symbiosis between rhizobia and their plant hosls requires multiple interactions between the two pnrtners, which involves transmission of signal molecules activating gene sets controlling nodule development. Plant roots exude specific Oavonoids which can induce the expression of the nodulation (nod) genes in the appropriate bacterium partner, in conjunction with the constitutively produced activator protein NodD. Additional positive and negative regulatory factors further modulate nod gene expression and this fine tuning of 110d gene expression is required for optimal nodulation of the hosts. Some of these factors mediate the effects of some soil factors, such as (he …


Effects Of Vesicular-Arbuscular Mycorrhiza Inoculation, Nitrogen And Phosphorus On The Growth Of Seedlings Of Sesbania Sesban, E Akeampong, T Mamo Sep 2024

Effects Of Vesicular-Arbuscular Mycorrhiza Inoculation, Nitrogen And Phosphorus On The Growth Of Seedlings Of Sesbania Sesban, E Akeampong, T Mamo

IGC Proceedings (1993-2023)

In the first of two pot experiments, growth of seedlings of Sesbania sesban in response to rates of P (0, 40, 120, 160 and 200 kg/ha) and of N (0 11nd 100 kg/ha) was examined. In a second trial the effect of inoculation with vesicular-arbuscular mycorrhiza (Glomus macrocarpus) and 2 levels (0 and 40 kg/hn) each of triple superphosphnte (TSP) and Egyptian rock phosphate (ERP) were studied. Response to P was linear to 80 kg/ha. Application of N improved the response of seedlings to P through enhanced P and N uptake. Application of N increased plant weight by …


Isolation Of A Multi-Functional Cellulase Cdna (Cele) From The Rumen Fungus Neocallimastix Patriciarum, Gang Ping Xue, K S. Gobius, C G. Orpin Sep 2024

Isolation Of A Multi-Functional Cellulase Cdna (Cele) From The Rumen Fungus Neocallimastix Patriciarum, Gang Ping Xue, K S. Gobius, C G. Orpin

IGC Proceedings (1993-2023)

A cellulase cDNA, ce/E, was isolated from a cellulose-induced cDNA library of the rumen fungus Neocallimastix patriciarum by screening for hydrolysis of carboxymethyl cellulose. In addition to its ability to hydrolyse carboxymethyl cellulose, ce/E enzyme was also able to degrade microcrystalline cellulose, methylumbelliferyl cellobioside, p-nitrophenyl cellobioside, lichenan and xylan. These data suggest that ce/E encodes a multi-functional cellulase.


Cellobiohydrolase (Cbh) From Neocallimastix Patriciarum: A Membrane Associated Complex?, J H. Alyward, Gang Ping Xue, G D. Simpson, C G. Orpin Sep 2024

Cellobiohydrolase (Cbh) From Neocallimastix Patriciarum: A Membrane Associated Complex?, J H. Alyward, Gang Ping Xue, G D. Simpson, C G. Orpin

IGC Proceedings (1993-2023)

Three cellobiohydrolases were highly puriried from the rumen fungus Neocallimastix patriciarun. Two of these enzymes were liberated from insoluble material by extraction with the non-ionic detergent Triton X-114, requiring the presence of detergent or dissociating agent throughout their purification. The native cellobiohydrolase is probably membrane associated.


Effect Of Nitrogen Application On Symbiotic Nitrogen Fixation Of White Clover Ecotypes Collected In North-Eastern Japan, K Sugawara, A Nishiwaki, Y Yashima Sep 2024

Effect Of Nitrogen Application On Symbiotic Nitrogen Fixation Of White Clover Ecotypes Collected In North-Eastern Japan, K Sugawara, A Nishiwaki, Y Yashima

IGC Proceedings (1993-2023)

Escaped plants of white clover which could not be identified by variety were collected and were grown in pots filled with a perlite contained nutrient solution in a growlh chamber. On 16 of the collecled plants, the change of the nitrogenase activity by treatments with or without nitrogen (20 ppm N, NaNO3) was measured by gas chromatogrnphy and the variation of peroxidase isozyme was analysed by means of slab acrylamide gel electrophoresis. The studied plants of white clover (Trifolium repens L.) were classified into 5 types by the response pattern of nitrogenase to N applied. Six bands showing peroxidase …


Symbiotic Characterization Of Azide-Resistant Mutants Of Rhizobium Leguminosarum By Trifolii, Shashi Bhushan Sharma, K Sakadevan, R Corner Sep 2024

Symbiotic Characterization Of Azide-Resistant Mutants Of Rhizobium Leguminosarum By Trifolii, Shashi Bhushan Sharma, K Sakadevan, R Corner

IGC Proceedings (1993-2023)

Azide-resistant mutants of Rhizobium legumnosarum bv, trifolii strain NZPS61 were isolated. Mutations conferring azide resistance appeared at a frequency of 1.6x t0·7 on minimal media containing 25 µglml sodium azide. Two classes of mutants were observed with respect to the nitrogen source in the growth media. Mutants in the first class showed azide resistance in the presence of both nitrate and ammonia whereas the mutants in the second class showed azide resistance only in the presence of nitrate. Eleven azide-resistant mutants were characterised for their symbiotic ability with white clover. All the mutants were similar to their parent strain NZPS61 …


Intake Of South African Mutton Merino Ewes On Wheat Stubble Grazing, T S. Brand, J M. Van Heerden, F Franck Sep 2024

Intake Of South African Mutton Merino Ewes On Wheat Stubble Grazing, T S. Brand, J M. Van Heerden, F Franck

IGC Proceedings (1993-2023)

Wheat stubble was grazed continuously for 154 days during the summer (December-April) by reproducing and dry ewes (n-8) at 2 stocking rates ( 1 or 2 ewes/ha), Samples were collected for chemical analysis from oesophageally fistulated (OF) sheep. Intake was determined using controlled chromium-release devices. The mean CP, ADF and NDF contents and iii vitro OM digestibility of samples were respectively 16.1:t0.4%; 40.7:t0.8%, 59.0:tl.1% and 48.5±0.7% t 1 ewe/ha and 10.8±1.1%; 53.9±1.1%, 72.1±0.9% and 48.8:t0.7% at 2 ewes/ha. The mean CP intake of dry ewes was 202±7 g/day (I ewe/ha) and 113:t6 g/day (2 ewes/ha), while the CP intake of …


Earthworms In Pastoral Soils Of Northland, New Zealand, P W. Woods, A.R J. Christie, J N. Couchman Sep 2024

Earthworms In Pastoral Soils Of Northland, New Zealand, P W. Woods, A.R J. Christie, J N. Couchman

IGC Proceedings (1993-2023)

Earthworm populations were surveyed in 4S pastures in Northland, New Zealand. Both sheep and beef, and dairying properties were sampled during late winter. European liumbricid earthworm species encountered were Aporrectodea caliginosa, A. trapezoides, A. rosea, A. longa, Lumbricus rubellus, L. terrestris, L. castaneus and Octolasion cyaneum. Amynthas diffringens, a megascolecid of Asian origin, was also found. Three native megascolecid species were found under developed pasture. Shallow burrowing species such as Lumbricus rubellus and A. caliginosa were the most frequently encountered species, being present on 91% and 89% of sites, respectively. A. caliginosa was the main contributor to earthworm biomass. …


First Results On Growth Rates Of The Endophytic Fungi Acremonium And Epichloe On Solid And Liquid Media, P Dapprich, A Klose, V H. Paul Sep 2024

First Results On Growth Rates Of The Endophytic Fungi Acremonium And Epichloe On Solid And Liquid Media, P Dapprich, A Klose, V H. Paul

IGC Proceedings (1993-2023)

Growth rates of the ·grass endophytes Acrenonium lolii Latch, Christensen and Samuels, A. coenoplrialiim Morgan-Jones lind Garns and Epichloe typhina' (Fries) Tulasne were measured on different solid media under various conditions and in liquid medium. A. coenophiallum and E. ryphina developed best vegetative growth at 25°C in the dark ori;pofato-dextrose-ilgar (PDA) and on minimal­medium (MM), respectively. A: lo/ii grew best at 2coenophialum and E. typhina produced 1.48 g and 6 g FW, respectively. Within 3 days the conductivit)'. reached constant values.· Osmolarity decreased with the increase of biomass. pH rose in cultures of A. lolii and E. typhina …


Discovery Of Gynaephora Ruoergensis Nuclear Polyhedrosis Virus (Grnpv) And Its Use As A Baculovirus Pesticide In Qinghai-Tibet Plateau, Liu Shigui, Yang Zhirong, Wu Tieqiao, Zeng Ying, Cheng Shuqiu Sep 2024

Discovery Of Gynaephora Ruoergensis Nuclear Polyhedrosis Virus (Grnpv) And Its Use As A Baculovirus Pesticide In Qinghai-Tibet Plateau, Liu Shigui, Yang Zhirong, Wu Tieqiao, Zeng Ying, Cheng Shuqiu

IGC Proceedings (1993-2023)

A new pathogenic virus agent was isolated from the grassland caterpillar Gynaephora rnoergensis, an important pest of grassland in north-western Sichuan. Identification was based on morphological properties, biological characteristics and biochemical studies. It belongs to Subgroup A of the Baculoviridae, and has been named Gynaephora rnoergensis nuclear polyhedrosis virus (GrNPV). A viral pesticide was prepared using GrNPV. It has a killing efficiency of mote than 84.3% to grassland caterpillars, and has been applied for biological control of the pest to 2.3 million ha of grassland in north we􀁏tern Sichuan grassland and the Qinghai-Tibet,plateau.


Infection By Bdellovibrio Bacteriovirus Of Leguminous Forage Rhizobia, Xu Heng, Liu Shigui Sep 2024

Infection By Bdellovibrio Bacteriovirus Of Leguminous Forage Rhizobia, Xu Heng, Liu Shigui

IGC Proceedings (1993-2023)

Two bdellovibrio bacteriovirus infecting rhizobia of leguminous forage were isolated from Sichuan-Tibet plateau grassland. The culture characteristics, host range and other biological properties of two bdellovibrio bacterioviruses were researched. Research indicated that the two bdellovibrio bacterioviruses had a wide host range and a strong lyslng ability with Rhlwbium melilotl, R. trlfolll and R, astragalll. 8dellovibrio bacterioviruses affected nodu lation of leguminous forages in grassland, and are one of the main biological factors that lower the yield of leguminous forages.


Studies On The Mutagenicity Of Gynaephora Ruoergensis Nuclear Polyhedrosis Virus (Grnpv), A New Biological Pesticide, Liu Shigui, Wu Yong, Zeng Ying, Wu Tieqiao, Yang Zhirong Sep 2024

Studies On The Mutagenicity Of Gynaephora Ruoergensis Nuclear Polyhedrosis Virus (Grnpv), A New Biological Pesticide, Liu Shigui, Wu Yong, Zeng Ying, Wu Tieqiao, Yang Zhirong

IGC Proceedings (1993-2023)

To test pathogenicity and mutagenicity of Gynaepllora ruoergensis nuclear polyhedrosis virus (GrNPV), a new biological pesticide, acute and subacute infection tests were carried out in 366 vertebrates (16 species). Results indicated that GrNPV has no toxicity to vertebrates. No mutagenicity to Salmonela. typhimium . was found using the Ames.test. Four tests using cytogenelic methods, sister chromosome exchange (SCB), chromosome aberration test, a micro-nuclear test of mouse eosinophH cells, and lethal effect tests, indicated no mutagenictic effects to vertebrates.


Survey For Natural Enemies Of Leafy Spurge Of Rangeland In Northern China, Wang Jian Feng Sep 2024

Survey For Natural Enemies Of Leafy Spurge Of Rangeland In Northern China, Wang Jian Feng

IGC Proceedings (1993-2023)

Leafy spurge (Euphorbia esula L,) is a serious. toxic weed in the real Plains region of lhe USA and Canada where it is toxic to s9me; classes of livestock and displaces more desirable forage plants. Leafy spurge is also spreading widely in Inner Mongolia rangeland, but it does limited damage. Biological weed control scientists from China, USA and Canada have co-operated in a survey for natural enemies of leafy spurge.in Innc Mongolia rangeland where there is an abundant diverse assemblage of insects and pathogens , including: Aphthona , chln ch ichi, Apthona s.eriata, Oberea prob . erythrocephala, Chamaespecia sp. …


A Method For The Greenhouse Evaluation Of Subterranean Clover Breeding Lines For Phytophthora Clandestina Root Rot, S P. Flett, P A. Taylor, V Wakley Sep 2024

A Method For The Greenhouse Evaluation Of Subterranean Clover Breeding Lines For Phytophthora Clandestina Root Rot, S P. Flett, P A. Taylor, V Wakley

IGC Proceedings (1993-2023)

Subterranean clover root rot, caused by Phytophthora clandestina, is a serious disease in both irrigated and dryland pastoral regions of Australia. An Intensive program of screening cultivars and genetic lines of subterranean clover from the National Subterranean Clover Improvement Program (NSCIP) for resistance to root rot caused by Phytophthora clandestina is described, Subterranean clover (Trifolium subterraneum L.) lines, divided into screening runs, were infected with isolates of P. clandestina in a cooled greenhouse and each run required 11 weeks for complete evaluation, Each line was rated for root rot resistance ogainst a standard resistant cv. Larisa and a …


Monthly Changes In Plant Biomass, Net Primary Productivity And Transfer Dynamics Of A Tropical Grazing Land Ecosystem In Southern India, K.S T.K Karuniachamy, K Paliwal Sep 2024

Monthly Changes In Plant Biomass, Net Primary Productivity And Transfer Dynamics Of A Tropical Grazing Land Ecosystem In Southern India, K.S T.K Karuniachamy, K Paliwal

IGC Proceedings (1993-2023)

Monthly changes in plant biomass, net primary productivity and transfer dynamics of tropical grazing land of western Ghats region, southern India, are presented. The annual above- ground net production was 9.03 g/m2/day and the below-ground net production was 2.56 g/m2/day. Total annual net primary production was estimated at 4232 g/m2/day. Of the total input of 11.59 g/m2/day into the system, about 77.9% was channelled to above-ground and 22.1% to below­ground, The rate of litter disappearance was 0.55 g/m2/day and l.14 g/ m2/day for below-ground disappearance. The total output was 1.69 g/ m2/day which was 14.6% of the total input. Thus, …