Agronomy and Crop Sciences Commons^™

Rhoma Black Stem Disease- A Threat To Susceptible Annual Medic Pastures, M J. Barbetti

IGC Proceedings (1977-2023)

Phoma black stem disease, caused by Phoma medicaginis, is the most important fungal disease of annual Medicago spp. (medic) pastures in Western Australia. It is readily seed-borne and this provides an important inoculum source for spreading the disease into new sowings in areas free of leguminous crop residues. The disease produces dark brown to black lesions on cotyledons, leaves, petioles and stems and can cause leaf drop and petiole and stem collapse, Reductions in herbage production of up to 169!, and seed yield of up to 209!, have been recorded in grazed swards, while in ungrued swards, losses in herbage …

Effectiveness Of Acremoniu Lolli In Annual Ryegrass In Controlling Greenbug (Schizaphis Graminum Rondani) Injury, L R. Nelson, Marta R. Harrington, D Marshall

IGC Proceedings (1977-2023)

This experiment tested 3 ryegrass (Lolium multiflorum Lam.) genotypes with (E+ )° and without (E-) endophyte, to determine the effectiveness of the endophyte in reducing leaf damage caused by greenbugs (Schlzaplris granthum Rondani). Results Indicated that presence of endophyte increased resistance in only I of 3 lines tested. The apparent resistance was observed.as leaf necrosis (leaf necking, yellowing, tip die-back, and leaf death). Resistance was not observed until green bug reinfestation of 3-month-old plants. A control with E+ Kentucky 31 fescue (Festuca arundinacea Schreb.) also had reduced greenbug damage compared with E- Kentucky 31 plants. This study …

Invertebrate Pests Of Endophyte-Infected And Endophyte Free Perennial Ryegrass Swards In Northern New Zealand, R A. Prestidge, R N. Watson, E R. Thom

IGC Proceedings (1977-2023)

Plots of endophyte-infected and endophyte-free perennial ryegrass (Lollum perenne) cv. Ellett and white clover (Trifolium repens) cv, Grasslands Pitau were established in autumn 1990 by direct drilling into pastures previously sprayed with glyphosate herbicide. Plots were rotationally grazed by dairy cows. Insect pests were sampled by soil coring and extraction, and plant pathogenic nematodes by root staining and examination. Ryegrass tiller density and the proportion of ryegrass in the swards were-significantly less in November, March and May on plots sown with endophyte-free ryegrass c_ompared with endophyte-infected ryegrass. Conversely, the propo!'tion __ of white clover was greater on endophyte-free …

Invertebrate Pests Associated With Italian Ryegrass In Northern New Zealand, R A. Prestidge, R N. Watson, E R. Thom

IGC Proceedings (1977-2023)

Damage threshold levels were established for adult Argentine stem weevil (Listronotus bonariensis (Kuschel)) feeding on Italian ryegrass (Lolium multiflorum Lam;) cv, Concord seedlings in a glasshouse pot trial. Population densities of 35-70/m1 reduced seedling survival by 34% and herbage yield after 28 days growth by 35%. A field trial was established In autumn 1991 by sowing Concord in early February, in late February and in March into areas previously treated with glyphosate herbicide, Insecticide application increased ryegrass tiller density by 36% from 2339/m' (April 1991) and herbage accumulation by 43% from 1.4 t DM/ha only up to the …

Screening For Biological Control Agents Of Root Pathogens Of Pasture Legumes, R A. Skipp, F S. Hay

IGC Proceedings (1977-2023)

Fungi isolated from roots of legumes from pasture soil were applied to seeds of red clover (Trifolium pratense L.) on water agar in Petri plates in a seedling screening test designed to detect antagonism to the fungal pathogens Fusarium solani, Trichrocadium basicola and a Pythium sp. Isolates of Triclroderma koningii, T. /ramatum, a binucleate Rhizoc1011ia sp. or an unidentified basidiomycete protected seedling roots from damage by one or more of the fungal pathogens. Fungi isolated from cysts of the plant-parasitic nematode Helerodera trifolii obtained from pasture soil were tested for their ability to infect eggs of H. trifolii …

Effects Of Three Viruses On Productivity Of Annual Pasture Legume Swards, R A. C Jones

IGC Proceedings (1977-2023)

The effects of 3 non-persistently aphid-transmitted viruses on the productivity of swards of annual pasture legumes were investigated in 1988-91. Virus-host combinations studied were alfalfa mosaic virus (AMV) in burr medic (Medicago polymorplia), cucumber mosaic virus (CMV) in subterranean clover (Trifo/i111n subterra11eum) and bean yellow mosaic virus (BYMV) in subterranean clover. Swards were mown to simulate grazing, grazed or left undefoliated. Herbage (dry weight) and seed production were decreased significantly by infection with all three virus-host combinations. However, the extent of losses vnried with extent of virus spread, cultivar, site and season. Decreased seed yield resulted from both fewer and …

Burial Of Surface-Applied Lime By Earthworms In South Australian Pastures, G H. Baker, P. M.L Williams, V J. Barrett, P J. Carter

IGC Proceedings (1977-2023)

The ability of earthworms, Aporrectodea trapewides, A. caliginosa, A. rosea (Lumbricidae) and Gemascolex walkeri (Megascolecidae), to bury surface-applied lime and offset soil acidity was investigated in 2 pastures in the Mount Lofty Ranges, South Australia, In one pasture, A. trapewides increased pH by 0.8 of a unit at 4-6 cm depth. A. caliginosa also increased soil pH compared with controls, but A. rosea and G. walkeri had no influence, A. trapewides is suggested as a valuable addition to acid pastures, if not already present,

Effects Of Fungicide Seed Treatments On Germination And Establishment Of Sainfoin And Other Legumes, Nan Zhi Biao, Liu Zhao Hui, R A. Skipp

IGC Proceedings (1977-2023)

Treatment of seed with thiram or thiophanate methyl at a rate of 3 g ai/kg seed increased germination of crownvetch (Coro11illa varia L.), milkvetch (Astragalus ads11rge11s Pall.), sainfoin (011obrycl1is viciifolia Scop.) and yellow sweet clover (Melilotus officinalis (L.) Lam.) in laboratory tests. The magnitude of the increases varied with fungicide and species. The greatest increase in germination relativ!) to that of untreated seed was 115% for sainfoin dusted with thiophanate methyl. Thiophanate methyl increased field emergence of sainfoin at 4 and 8 weeks after sowing by 41% and 55% respectively, and at 8 weeks increased the dry weights of shoots …

Pastures In Crop Rotations Enhance Earthworm Populations In Southern Australia, John C. Buckerfield

IGC Proceedings (1977-2023)

The effects of crop rotations on earthworm populations in seasonally dry arable lands was assessed on long-term field trials at 2 sites with an annual rainfall of 450-500 mm, In cropping and sheep-grazing areas of southern Australia. Earthworm densities were substantially higher in rotations of cereals with a volunteer-pasture phase than under continuous cropping with cereals and grain legumes. The degree and frequency of soil disturbance associated with cropping has been shown to influence earthworm numbers: trial plots In which crops were sown with minimal cultivation, in alternate years, supported earthworm populations 2-3 times higher than those conventionally cultivated and …

Costs And Benefits Of Controlling Grasshoppers On Rangeland, E W. Huddleston, R Sanderson, L A. Torell, J H. Davis, J G. Watts

IGC Proceedings (1977-2023)

Ultra low volume (ULV) aerial application of malathion at 0.58 I/ha is the common method of rangeland grasshopper control in the USA. Aircraft often are unavailable or too expensive for treating small infestations; therefore, air-assist ground equipment was adjusted 10 apply the ULV rate from a small truck. In winds of 2.2 m/sec or greater, control with the ground equipment was equivalent to that expected from aircraft. The low spray volume, low sprayer cost and use of a small truck have increased the benefit/cost ratio. Using results from this research and site-specific estimates of control costs and forage value, the …

The Rodent Pests Of Pasture And Their Control In China, Xixian Hou, Weihui Dong, Yanlin Zhou

IGC Proceedings (1977-2023)

Rodent damage is increasingly recognised as a major problem for grasslands of China rodents damage up to an estimated 33 million ha each year, There are two reasons for rodent damage in grassland: one is overgrazing, which causes degeneration of grassland and provides good habitats for rodents; another is the ecological characteristics of rodents. A rodent control programme has been followed for years in China, and includes: (1) studies on the ecology of major rodent pests in pasture, (2) prediction of population, (3) setting up control indexes paying attention to economic benefits, (4) tightening up grassland management and developing integrated …

Stylo Host Heterogeneity For Anthracnose Management, S Chakraborty, A N. Petitt, R M. Boland, S Low Choy, D F. Cameron, J A.G Irwin, R D. Davis

IGC Proceedings (1977-2023)

Small plots of 3 different mixtures of Stylosallllles. scabra genotypes were established within background paddocks of either pure cv. Seca, or a mixture of 6 S. scabra genotypes including Seca, to study anthracnose development in the three mixtures under exogenous inoculum pressures arising from the two backgrounds. There was no difference in disease severity between the background paddocks after the first year. In the small plots, severity of nearest neighbours significantly influenced anthracnose severity on the partially resistant accession 55860 in the first year; this effect disappeared as the disease became more widespread throughout the plot in later years. Replacing …

Increased Resistance To Sclerotinia Crown And Stem Rot Of Alfalfa Through Recurrent Selection Of Surviving Plants In Inoculated Field Plots, M Kanbe, F Fujimoto, S Inami

IGC Proceedings (1977-2023)

ABSTRACT Breeding alfalfa (Medicago saliva L.) for resistance to Sclerotinia crown and stem rot (SCR; causal agent Sclerotitivia trifoliorum Eriks.), which is a serious disease in Japan, was started in 1983. Increased resistance to this disease has been examined after repeated selected of surviving plants from artificially inoculated field plots to the 5th generation. The strains selected for SCR resistance showed higher resistance than Tachiwakaba, which was the main breeding material. The effectiveness of selection judged by the survival rate of progenies was low in the early selection generations but high in the later ones, It is considered that …

Biological Control Of Alfalfa Aphids In Japan Using Coccinella Septempunctata Brucki, Keiichi Takashi

IGC Proceedings (1977-2023)

The oviposition, predation, and survival abilities of Coccinella septempuncrara bmcki Mulsanl (lady beetle), a natural enemy of alfalfa aphids (Acyrtllosyphon kondoi Shinji), increased as temperatures rose in laboratory tests. The second-instar larvae were released into cages in alfalfa (Medicago saliva L.) fields in spring 1991. One month later, alfalfa plants in the control cages without larvae showed much lower yield; however, no damage was observed in cages in which larvae had been released. There is a strong probability that alfalfa aphids can be controlled by the timely release of lady beetle larvae in the field.

Incorporation Of Undissolved Lime From Previous Applications Can Ameliorate Subsoil Acidity Promptly And Improve Crop Performance On Sandy Soils Of The Semi-Arid Regions Of Western Australia, Gaus Azam, Md. Shahinur Rahman

Grain and Other Field Crops Research Articles

Background and aims

Repeated surface application of lime for managing subsoil acidity is slow and ineffective, resulting in an accumulation of undissolved lime (carbonate) in the topsoil. We investigated the impact of the incorporation of undissolved lime into the subsoil to improve acidity and crop performance.

Methods

The undissolved lime in 2-cm layers of topsoil (0–10 cm) from three long-term experiments in Western Australia was measured. Both limed and unlimed topsoil with the acidic subsoil of the same profile was incubated at eight incorporation rates for six weeks, followed by growing barley and wheat in the incubated soil for two …

Development Of Intensive Grassland Systems: From Science To Practice, D G. Mccall, G W. Sheath

IGC Proceedings (1977-2023)

Level of nnimal production from grassland is determined by the amount of pasture grown, pasture utilisation and animal conversion efficiency. The key components affecting production are pasture growth and animal conversion efficiency. These arc mainly influenced by environment, genetics and through inputs to maintain soil fertility or animal health. Systems development aims to link pasture growth and animal conversion through efficient strategies for pasture utilisation. The means of influencing pasture utilisation is through adjustments to animal feed demand, feed supply or grazing management. Stock policies that adjust the pattern and level of feed demand are of greatest significance in developing …

The Ecology Of Grazing Management, R K. Heitschmidt

IGC Proceedings (1977-2023)

The broad objective of this paper is to review the fundamental principles of grazing management as a means of assessing the inherent value of intensive and extensive grazing systems. Conceptual analyses of intensive and extensive grazing systems reveal that the fundamental differences between intensive and extensive grazing systems are related to differences in non-grazing rather than grazing tactics. Intensive grazing systems employ a wide array of non-grazing tactics in an attempt to overcome the inherent ecological constraints that limit secondary (i.e., livestock) productivity in extensively grazed systems. Moreover, analyses of the ecological or true efficiency of various agricultural production systems …

An Analysis Of The Dry Matter Intake And Rate Of Live-Weight Gain Of Growing Cattle Fed Forage Diets, J G. Buchanan-Smith

IGC Proceedings (1977-2023)

The intake and rate of live-weight gain of 500 growing steer calves fed experimental forage diets in 7 trials were compared with corresponding values predicted using the Na1ional Research Council (NRC) model (1984). The cattle were predominantly weaned calves and most of the experimental diets were alfalfa-grass silage, either unsupplemented or supplemented with various protein sources, but some diets were based on maize silage or maize grain. The feeding period evaluated in this study ranged between the first 84 and 147 days when protein accretion rate in the cattle would be relatively high. Dry matter intakes were overpredicted by the …

Management Of Extensive Pastures For Dairy Youngstock, G.E J. Fisher, D J. Roberts

IGC Proceedings (1977-2023)

The effects of low input systems on the ground cover of species and yield and chemical composition of herbage cul from extensive lowland swards was studied over 3 years. The live-weight gain of dairy heifer replacements offered grazed or conserved forage from these pastures was also assessed, The swards were sown with a mixture of grasses, wildflowers and herbs and received no inorganic fertilizers, Applications of slurry in January and February increased herbage yield by 43%, but reduced the cover of flowers and herbs. Using a 2- cut conservation system improved yield of metabolisable energy/ha in herbage by 33%, and …

Intensive Grazing Of Alfalfa By Beef Steers, M Rasnake, W R. Burris, G D. Lacefield, J Randolph, N Gay, L Davis

IGC Proceedings (1977-2023)

In the temperate region of North America, high temperature and moisture deficit cause low forage growth during the summer of most years, making it difficult to grow beef (Bos taurus), calves through summer grazing. Alfalfa (Medicago sativa), offers some potential to provide high dry matter production during summer if an effective system of grazing can be developed. The objective of this study was to test a system of intensive grazing of beef steers on alfalfa to maximise live-weight gains/ha and maintain plant population. Alfalfa was no-till seeded into a 6.5 ha field in autumn 1988 after …

Variance Across Years In Growth Of Cattle On Annual Pastures In A Mediterranean Climate, K D. Greathead, J Zorrilla Rios

IGC Proceedings (1977-2023)

Annual pastures were continuously grazed by new drafts of yearling cattle each year for 4 years at 2 sites. The variability of weight gained across years at any date was not different between sites. The level of rainfall in April, but strongly influenced weight gained by the cattle in any year. Variances in weight change were small up to April, they increased rapidly from April to late July and were not different after July (P<0.05).

Modification Of The Botanical Composition Of Perennial And Annual Temperate Pastures By Strategic Grazing Practices, D R. Kemp, P M. Dowling

IGC Proceedings (1977-2023)

Where livestock production depends upon pastures, management is more difficult in environments where rainfall varies considerably from season to season and year to year. Flexible grazing practices are needed to optimise species composition and pasture productivity. Results presented in this paper show that pasture composition can be improved within climatic constraints, by grazing practices within seasons, In temperate annual pastures, long rests in winter (similar to a long rotation during that season) increased annual legume content in early spring from 20 to 50%. Annual grass content was unchanged. In perennial (phalaris) pastures, the dominant legume can change over years from …

Development Of Grass-Clover Pasture Systems For Autumn-Calving Beef Cows. I. Forage Production, G D. Mooso, D G. Morrison, J I. Feazel, D R. Morris

IGC Proceedings (1977-2023)

Four 8-ha areas of bermudagrass-based (Cynodon dactylon (L.) Pers.) grazing systems were sodseeded and received annual N fertiliser as follows: I) clover (Trifolium sp.)+81 kg Nnm, 2) annual ryegrass (Lolium multiflorum Lam)+clover +81 kg N/ha, 3) ryegrass+clover+l39 kg N/ ha, and 4) ryegrass+139 kg N/ha. Monthly forage accumulation was estimated for 3 years by clipping samples from 2 exclosures/pasture. Environmental conditions had a significant effect on total annual forage dry matter (DM) production. Systems 3 and 4 produced more (P<0.05) forage DM than Systems 1 and 2 (11.0 v. 10,3 Mg/ha). System I produced more (P<0.l) forage DM than 2 (10.6 ll, 9.8 Mg/ha). Systems 3 and 4 were similar, producing I 1.0 Mg/ha. Monthly forage accumulation was lowest in winter (December to February) and highest in spring and summer (March to August). The results of this study demonstrate that at a low N level, there was no benefii from including ryegrass in the system and al a moderate N level, there was no benefit from including clover.

Development Of Grass-Clover Grazing Systems For Autumn-Calving Beef Cows. Ii. Cow-Calf Production And Economic Analysis, D G. Morrison, J I. Feazel, G D. Mooso

IGC Proceedings (1977-2023)

Four 8-ha areas of bermudagrass-based (Cynodon dactylon (L.) Pers.) grazing systems were sod seeded and received annual N fertiliser as follows: I) clover (Trifolium sp.)+81 kg/ha, 2) annual rye grass (Lolium multiflorum Lsm.)+clover +81 kg/ha, 3) ryegrass+clover+139 kg/ha, and 4) ryegrass+l39 kg/ha. Each system was stocked year-round with 20 (2,5/lla) cows each with crossbred suckling calf. Cow and calf performance data for 3 of 4 years are included. Year affected (P<0.01) cow and calf live weight, Cows in System 2 were 25-50 kg lower in live weight in autumn and winter than cows in other systems. From February to July, cow daily live-weight gains were 0.11 kg higher (P<0.01) for Systems 2 and 3, Cow live weight in July was affected by N level (Systems 1,2<3,4; P<0,01), Year by system interactions (P<0.05) occurred for cow live weight in February, April and July because of live weight increasing over years in Systems 3 and 4 but not in Systems 1 and 2. Calf daily live-weight gain February to weaning (July) was higher (P<0.01) for System 2 v. 1 (0.06 kg), Syuem 3 v. 4 (0.07 kg), and Systems 3, 4 v. 1, 2 (0.07 kg), Estimated net returns favoured Systems 3 and 4 over Systems 1 and 2.

Improved Grazing Systems For Lamb Production On Appalachian Hill Farms, R L. Reid, J R. Puoli, G A. Jung, D P. Belesky

IGC Proceedings (1977-2023)

Improved grazing methods were tested to increase lamb outputs per ha from Appalachian hill farms. Components of a grazing system were cool-season grass [tall fescue (Festuca arundinacea Schreb.), Grasslands Matua prairie grass (Brom us willdenowii Kunth)J or grass­legume [Kentucky bluegrass (Poa pratensis L.)•red clover (Trifolium pralense L.)] pastures in spring and early autumn, warm-season grass [switchgrass (Panicum virgatum L.)] in summer, and brassicas in late autumn and early winter. Matua was highly productive in cool weather but was subject to fungal infection and grazing ewes had low Mg status in spring. Rotationally grazed switchgrass maintained high numbers …

Use Of Brassica Forage Crops To Extend The Grazing Season In The North-East Usa, G A. Jung, H W. Harpster, M G. Lambert, K T. Leath, R A. Byers

IGC Proceedings (1977-2023)

Forage turnip (Brassica rapa L,) can be made available for animal utilisation in late summer or In late autumn-early winter, when cool­season grass pastures have a low animal carrying capacity. field trials were conducted to identify and quantify factors that influence turnip yield in December or January and to determine whether these factors affect turnip cultivars similarly. Different levels of production in late autumn-winter were attributed to summer drought, foliar diseases, freezing temperatures and rate of leaf senescence. In all instances, the effects of these factors varied with turnip cultivar. However, cultivar ranking generally was the same whether mean …

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

IGC Proceedings (1977-2023)

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

IGC Proceedings (1977-2023)

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

IGC Proceedings (1977-2023)

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

IGC Proceedings (1977-2023)

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 …