Plant Pathology Commons^™

Potential Of Aeschynomene Sp. For Pastures In The Tropics, A E. Kretschmer Jr, G H. Snyder

IGC Proceedings (1977-2023)

The objectives of this study were to assess the forage potential of readily available world germ plasm of the genus Aeschynomene, which comprises 160 species; to compare some attributes of the commercial American jointvetch (Aeschynomene americana L.) with those of other accessions of the same and of other species; and to compare the seasonal growth pattern and response to phosphorus (P) of commercial jointvetch with two perennial tropical legumes. Evaluations were made of 342 accessions, including 25 identified species. Data collected from observational plots in 1978 and 1980 included initial flowering dates, plant vigor, and growth habit; from replicated plots, …

Some Initial Results Of Field Trials Conducted In Establishing A Pasture-Seed Industry In Cojedes State, Venezuela, E.J A. Khan, W H. Mark

IGC Proceedings (1977-2023)

In starting a pasture-seed industry on a farm located at lat 9°50' N that gets about 1,600 mm of rain yearly followed by a severe dry season from mid-December to April, four widely separated sites were selected to plant three grasses for commercial seed production in 1978. The objectives were to assess the fertility status of the soils, then to determine the fertilizer re­quirements of the grasses at each site and to establish an introduction garden with 70 cultivars of grasses and legumes to study their suitability for expanding seed production. Based on the results of soil analyses, a modified …

Insect Pests Of Tropical Forage Plants In South America, Mario Calderon

IGC Proceedings (1977-2023)

The objectives of this continuing research are to make a general survey of the insect populations occurring on tropical forage plants in South America and to identify the most important pests. To realize this investigation, pure stand plots 5 X 5 m were sampled every 14 days during 2 years using a D-Vac. Vacuum Sampler.

The following information was obtained:

• Most important families and/or genera of insects in tropical forage legumes and grasses. • Insect group frequency for each season. • Insect group frequency for each plant ecotype under study. • Preliminary data on insect preference. • Preliminary data …

Sown Grassland As An Alternative To Shifting Cultivation In Lowland Humid Tropics, H R. Chheda, O Babalola, M.A M. Saleem, M E. Aken'ova

IGC Proceedings (1977-2023)

Agriculture based on existing forms of shifting cultivation will not be able to support and feed adequately the rapidly increasing human population of the lowland humid tropics of Africa. The forest and natural fallows have shortened and even disap• peared in some areas because of rising food demands. Crop yields are low and continue to decline. What, then, are the alter­natives? Using Cynodon as an example, an attempt is made to show that mixed farming offers an alternative whereby the nutrient status and physical properties of the soil can be maintained, erosion can be checked, weeds can be kept under …

Animal Production From Brazilian Tropical Pastures, G L. Rocha, V.B G. Alcantara, P B. Alcantara

IGC Proceedings (1977-2023)

This review deals with the potential for beef production from nitrogen- and legume-based pastures in tropical Brazil. Possibilities for impr􀀞ving the beef industry supported by grass-legume pastures are very promising. According to the literature examined, legume-based pastures produced an annual average of 329 kg gain/ha, and nitrogen (N) fertilization resulted in 4.56 kg gain/ha. Phosphorus (P) was the main fertilizer utilized in addition to N, followed by potassium (K), lime, and micronutrients. An­nual rainfall averaged 1430 mm. Grasses used were of the genera Melinis, Hyparrhenia, Panicum, Cenchrus, Digitaria, Cynodon, Brachiaria, and Pennisetum, and the legumes were of the genera Macroptilium, …

Verano Stylo In Semiarid Northeastern Thailand, A Topark-Ngarm

IGC Proceedings (1977-2023)

Srylosanthes hamata cv. Verano was first introduced to Thailand in 197 5. In the northeastern part of the country where the climate is marginal and the soils are low in fertility, Verano appears to be one of the most suitable forage legumes used in pasture-improvement programs. Verano can be grown satisfactorily on most soils in the northeast. Oversowing the seed at 3.1 kg/ha on unploughed areas resulted in a density of 5-30 plants/m2, while in cultivated land the same amount of seed gave 20-45 plant/m2 • In a 3-year ex­periment under different seeding rates and cutting intervals Verano outyielded three …

Hemarthria Altissima: A Pasture Grass For The Tropics, K H. Quesenberry, W R. Ocumpaugh, O C. Ruelke

IGC Proceedings (1977-2023)

Limpograss (Hemarthria altissima [Poir] Stapf. et C.E. Hubb), introduced into the U.S. in 1964, has been evaluated for use as a pasture grass. Under Florida conditions it has shown yield potential equal to or greater than other tropical pasture grasses. The cultivar Bigalta has higher in-vitro organic-matter digestion (IVOMD) than other tropical grasses at comparable growth stages. Early evaluations of limpograss involved only three clones, but additional genotypes were collected and introduced during the late 1960s and early 1970s, and an evaluation scheme for this germ plasm was undertaken. Our objectives were to evaluate rapidly the available germ plasm of …

Level Of Nitrogen Fertilizer In Annual Winter Pasture (Oats-Ryegrass) And Summer Pasture (Millet): Effects On Milk Production, C J. Olivo, I L. Barreto, D A. Stiles

IGC Proceedings (1977-2023)

Two experiments were conducted with lactating Holstein cows to study the effects of different levels of nitrogen fertilizer (urea) on annual pasture: experiment 1, oats (Avena byzantina K. Koch) and ryegrass (Lolium multiflorum Lam.); experiment 2, millet (Pennisetum americanum (L.] Leche). Base fertilizer (8-28-18) was applied, and at the five-leaf stage three levels of nitrogen (N) (75, 150, and 225 kg/ha) were applied. The millet pasture followed the oat + ryegrass pasture, with the N treatments being maintained in the same areas. Two ha were planted for each treatment (total, 6 ha). In experiment 1, twelve lactating cows were randomly …

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 …

A Comparative Evaluation Of Six Ryegrass Cultivars Under Grazing And Conservation Managements, M Ryan

IGC Proceedings (1977-2023)

Meat and dairy products command overriding importance in the Irish agricultural economy. They are derived primarily from Irish grasslands, which occupy 89% of the arable land area. Use of improved grass cultivars is probably the best means of increasing grassland output once the basics, optimal fertilizer use, and high stocking rates have been met. Objective identification of superior cultivars is the responsibility of state agencies. A recommended list, published annually in Ireland, presently contains 47 ryegrass (Lolium perenne) cultivars. There is some doubt, however, that results from small-plot cutting trials can be extrapolated to equivalent performance by grazing …

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 ( ± …

Chinas Grassland Types: Their Locality And Improvement, Chia Shen-Siu

IGC Proceedings (1977-2023)

China's natural grassland is mainly distributed over the temperate zone to the west and north of the isohyet of 400 mm annual rainfall and over the hilly subtropical areas in the southern part of the country, amounting to 3 7 % of the country's total land area. Since 1949, comprehensive surveys have been conducted on several occasions in Tibet, Neimenggu Autonomous Region (Inner Mongolia), Xinjiang, and other regions. The resource of forage plants and grassland productivity has been studied. There are about 20 types and eight regions of grassland in China. On the natural steppe of the northern part of …

Production Response Of Russian Wildrye (Elymus Junceus Fisch.) To Fertilizer And Clipping, L Hofmann, J F. Karn

IGC Proceedings (1977-2023)

Experiments were conducted on nitrogen (N) fertilization of long-term Russian wildrye (RWR) (E?Jimus junceus Fisch.) pasture and the effect of simulated spring grazing on quantity of forage available for fall use. A stand of RWR that had been fer­tilized with 45 kg N/ha and grazed annually for 10 years at Mandan, North Dakota, was divided into two experiments in 1978. The first evaluated effects from all combinations of 0, 45, 90, 135, 180, and 225 kg N/ha; 0, 45, and 90 kg phosphorus (P)/ha; and 0 and 135 kg potassium (K)/ha on dry-matter (DM) yields, whereas the second compared ten …

Changes In Quality And Composition Of Alfalfa During Autumn, S C. Fleming, M Collins, N A. Jorgensen

IGC Proceedings (1977-2023)

Autumn harvest of alfalfa (Medicago sativa L.) offers a potential for obtaining additional forage production during a particular season. Little is known about the quality or changes in the chemical composition of this forage. The objective of this research was to examine changes in chemical composition, dry-matter intake (DMI), and apparent digestibility of alfalfa during autumn in Wisconsin. An established stand of Vernal alfalfa, early bud to midbud, was harvested using a flail harvester on 5 and 20 October and 5 and 18 November 1979. The forage was dried at 55°C for 72 to 96 hours in burlap bags. A …

Stockpiling Of Cool-Season Grasses In Autumn, C T. Dougherty

IGC Proceedings (1977-2023)

The practice of accumulating growth of cool-season grasses in the late summer and early autumn for subsequent grazing in late autumn and winter, known as stockpiling, has been widely accepted by beef cow-calf producers. The objectives of our study were to determine the growth characteristics of cool-season grasses in the autumn under nitrogen (N) fertilization and to in­vestigate utilization of stockpiled forages. Tall fescue (Festuca arundinacea Schreb.) has many attributes that make it highly suited to stockpiling. On Maury silt loams, Kentucky 31 tall fescue accumulated 6,500 kg/ha of dry matter from 16 August 1979 to 12 December 1979 …

Potential Grass Production In Ireland, A J. Breeton

IGC Proceedings (1977-2023)

Variation in weather geographically and between years can have a significant impact on intensive animal production systems dependent on grass as feed. This work was undertaken to quantify the effect of weather variations on grass production. The first objective was to relate grass growth quantitatively to radiation and temperature. These relationships are obscured by large changes in sward growth potential within the season, which are related to changes in the physiological status of the crop. Therefore, it was necessary to quantify this physiological effect. Production data were drawn from production experiments, and weather data were drawn from the published records …

Ladino Clover Persistence As Affected By Physical Management And Use Of Pesticides, D S. Chamblee, L T. Lucas, W V. Campbell

IGC Proceedings (1977-2023)

Stand persistence is a major weakness of the widely used Ladino clover (Trifolium repens L.) in the U.S.A. The objective of these studies was to determine the influence of physical management practices and selected pesticides on longevity of Ladino clover stands. Ladino grown alone and in mixture with tall fescue (Festuca arundinacea Schreb.) was subjected to varying physical management regimes ( clipping, grass density, and spacing) and insecticide and fungicide applications in two tests for 5 to 6 years. By the fall of the third year, the percentages of clover (average of two tests) in the Ladino clover-tall fescue untreated …

Improvement Of Yield And Persistence Of Italian Ryegrass Through Pest Control, R O. Clements, I F. Henderson

IGC Proceedings (1977-2023)

Our objectives were to examine (1) whether increases in yield and persistence of Italian ryegrass varieties following frequent pesticide application are related to a reduction in frit-fly larval populations, and if so (2) whether the use of a nonpersistent pesticide would be a feasible method of reducing such damage. In two field experiments, the yield and persistence of normally short-lived Italian ryegrasses (Lolium multiflorumL.) were greatly increased by application of large and frequent doses of the potent insecticide phorate. Much of the insect damage was at­tributed to stem-boring dipterans of the frit-fly complex (e.g., Oscinella.frit).

In one experiment, small …

Minimizing Disease Losses In Forage Crops Through Management, K T. Leath

IGC Proceedings (1977-2023)

Diseases cause major losses in yield, quality, and stand life of forage crops. Strategies that are used to minimize such losses in­clude the use of resistant varieties and crop-management practices that directly or indirectly affect diseases. Because of the perennial nature of both the crops and the diseases, there are many opportunities to implement management strategies to reduce disease. Implementation begins prior to the planting of the forage crop and continues through the actual planting and on through the production years. Insect control, weed control, and fertility maintenance are examples of crop management that also serve to minimize forage-crop losses …

Sprinkling Irrigation Of Forage Plants Under Different Site Conditions In The Gdr, W Breunig, R Richteh, W Henkel, G Schaltz

IGC Proceedings (1977-2023)

Stability and continuity of forage production are primarily dependent upon the actual water supply and the level and distribution of nitrogen applications. Under the soil and climatic conditions in the GDR, in almost every year ther-e are certain periods when the natural water supply does not satisfy the water needs of forage plants, leading to severe yield loss unless sprinkle irrigation is practiced. As sprinkle irrigation is very costly and water resources are limited, we must make full use of all potential for achieving high yields while keeping the water input at a minimum -i.e., maximizing overall efficiency of the …

Maximum Production From Irrigated Rhodesgrass And Green Panic In A Mediterranean Environment, A Dovrat, T Kipnis

IGC Proceedings (1977-2023)

Aspects of the production of rhodesgrass (Chloris gayana Kunth) and green panic (Panicum maximum var. trichoglume) as roughage for high-grade dairy cattle when land and water resources are limited are described. Results from some 10 years of research are highlighted. The height of the canopy to which grasses should be allowed to regrow for maximum production is above the height that can be utilized efficiently when harvested in situ by cattle. Mechanical harvesting and indoor feeding provided 20%-25% more digestible dry matter/unit area of land (with a parallel increase in water-use efficiency) than strip grazing, almost without affect­ing …

Hydration-Dehydration As A Presowing Seeding Treatment Physiology And Application, W M. Lush, R H. Groves, P E. Kaye

IGC Proceedings (1977-2023)

Presowing hydration-dehydration treatments, in which seeds are partially hydrated and then dried back to their original weights before sowing, have been claimed to have wide-ranging and beneficial effects on seed germination and plant growth. We have assessed the physiological benefits and problems of hydration-dehydration treatments as they apply to pasture grasses, in particular to annual ryegrass. Pretreatment increased the speed of germination because the embryos of pretreated seeds were in a more advanced develop­mental stage at sowing. Furthermore, the germinability of seeds was increased if hydration-dehydration coincided with ex­posure to dormancy-breaking conditions, but we found no evidence to support other …

Increased Use Of Southern Piedmont Land And Climatic Resources By Interseeding Small Grains In Dormant Coastal Bermudagrass, S R. Wilkinson, J A. Stuedemann

IGC Proceedings (1977-2023)

Experiments were conducted to assess interseeding small grains by no-till methods in dormant Coastal bermudagrass (Cynodon dacrylon [L.] Pers.) for forage, silage, grain, or beef production. Wheat (Triticum aestivum L.) was interseeded in Coastal ber­mudagrass (CBG) sod. Grain yields of 1,695 kg/ha reduced CBG yields 14%, and silage yields of 6.7 tons/ha resulted in a 5 % reduction in CBG yield. The nitrogen (N) requirements for tall fescue (Festuca arundinacea Schreb. L.) or rye (Secale cereale L.) interseeded in dormant CBG for 90 % of maximum yield were similar at 166 and 17 5 kg N …

Silage Corn Cultivation On Degraded Pasture By Means Of Minimum Tillage, T Gemma

IGC Proceedings (1977-2023)

The purpose of this study was to investigate the possibility of silage com cultivation by means of minimum tillage for renovating degraded pasture in Hokkaido, Japan. Com (Wasehomare, a leading variety for silage in Hokkaido) was planted, in 4 replicates, on 23 May 1978 on the experimen­tal farm of the Obihiro University of Agriculture and Veterinary Medicine under the conditions of no tillage, strip tillage, and conventional tillage. Plant density was 75 x 25 cm. Fertilizers applied were N, P205 , and K20, at rates of 120, 150, and 100 kg/ha. Herbicides used were 5% EPTC, 10 kg/ha, and 47.5% …

Influence Of Grazing With Cattle On Establishment Of Forage In Burned Aspen Brushland, R D. Fitzgerald, A W. Bailey

IGC Proceedings (1977-2023)

The effect on establishment of introduced forages in aspen (Populus tremuloides) brushland of removal of suckers, by grazing with cattle early in the growing season or just before leaf fall, was investigated in central Alberta following burning of aspen forest in spring. In a year when moisture conditions were suitable, forage species were established successfully by broadcasting in spring shortly after the forest was burned. Suppression of competition from regenerating shrubs was necessary for forage seed­ling survival and improved establishment more when carried out early than when carried out late in the growing season. Cattle, when concentrated on the burned …

Grass Establishment: An Evaluation Of Seedling Characteristics Relative To Winter Injury Survival, And Earth Growth, R S. White, P O. Currie

IGC Proceedings (1977-2023)

Stand establishment in northern latitudes presents a challenging problem that must be conscientiously dealt with to obtain op­timum response from introduced grasses. Many variables have been studied in regard to establishment, but relatively little research has been done on early seedling growth and development per se. Yet early in growth is when plants are most vulnerable

to winter injury, dessication, competition, grazing, and other advene impacts. Our resea:rch has sought to identify some of the critical morphological features in seedlings that can influence grass establishment. Specifically, objectives were (1) to define and quantify relationships between morphological development and winter injury, …

New Methods For Establishing Grass In The Southern Great Plains, V L. Hauser

IGC Proceedings (1977-2023)

Native and introduced grasses are difficult to establish in the southern Great Plains. Seedling establishment is often prevented by rapid drying of the surface 2 or 3 cm of soil, in which most grass seeds are planted. Three new or nontraditional methods of avoiding the problem in establishing grass were studied. The first method was punch planting, in which the seeds were placed in the bottom of a deep open hole where the soil re­mained wet longer than surface soil. In the second method, the seeds were germinated before planting; thus, they emerged quickly to avoid the rapid drying of …

Renovation Of Tropical Legume-Grass Pastures In Northern Australia, H G. Bishop, B Walker

IGC Proceedings (1977-2023)

Live-weight gain of cattle on tropical legume-grass pastures is highly correlated with legume content. Legume-yield decline is a major problem in 200,000 ha of siratro (Macroptilium atropurpureum [DC] Urb.)-based pastures in northern Australia. This decline is largely associated with overgrazing. Resting for at least one year has been required to improve siratro yield substan­tially. A more rapid method of restoring the yield of siratro was required. The effect of various forms of mechanical soil disturbance on siratro population and yields was compared with resting pasture (control) in 4 replicated experiments and on 3 commercial pastures near Mackay in coastal northeastern …

Effectiveness And Safety Of Translocated Herbicides Applied To Pasture Weeds With A Rope-Wick Applicator, E J. Peters

IGC Proceedings (1977-2023)

Applying herbicides with a rope-wick applicator is a new technique that permits treatment of tall weeds without treatment of low-growing forage species. The objective of this study was to determine the effectiveness of several herbicides and to evaluate their safety to forage species. The effectiveness of 2,4-D [(2,4-dichlorophenoxy)acetic acid], dicamba (3,6-dichloro-o-anisic acid), picloram (4-amino-3,5,6-trichloropicolinic acid), and glyphosate [N-(phosphonomethyl) glycine] in water-herbicide con· centrations of 2: 1, 4: 1, and 8: 1 were evaluated on gray goldenrod (Solidago nemoralis Ait) when applied with a rope-wick ap· plicator in one and two directions on 15 June and 17 July 1979. The goldenrod …

Production Of Big Trefoil On Acid, Low-Fertility Soils In New Zealand, R S. Scott

IGC Proceedings (1977-2023)

On undeveloped, acid (pH< 5.0) soils in New Zealand, growth of the conventional legumes white clover (Trifolium repens L.), red clover (T. pratense L.), and alsike clover (T. hybridum L.) is limited by acidity. The objective of this research was to identify an alternative legume species better adapted to both acidity and low inputs of phosphorus (P) and to examine grazing management. Big trefoil (Lotus pedunculatus Cav.) cv. Grasslands Maku and birdsfoot trefoil (L. rorniculatus L.) cv. Maitland were examined. Seed was inoculated with appropriate strains of rhizobia and sown into undisturbed tussock grasslands on acid soils of low P status at altitudes of 550-880 m. Lime and phosphorus …