Plant Pathology Commons^™

Suitable Seed Harvesting Time For Six Grass Species, Hossein Arzani, A. Fakhireh

IGC Proceedings (1977-2023)

Determination of the best period of seed harvesting was considered. Six grass species were selected. The research was conducted in three stations of Alborz, Sirachal and Homand Absard. According to maturing stages, seed collection for measuring seed water content (moisture content), weight of 1000 seeds and germination percentage has been done. The result showed that there were significant differences between harvesting time on seed germination for all species in all regions. Moisture content, germination rate, weight of 1000 seeds and seed shedding were important characteristics for determination of suitable seed harvesting time.

Effect Of Nitrogen Fertilizer On Reproductive Tiller Development In Perennial Ryegrass, I. Bahmani, E. R. Thom, C. Matthew, G. Lemaire

IGC Proceedings (1977-2023)

The objective of this study was to compare reproductive tiller development in two ryegrass (Lolium perenne L.) cultivars, when fertilized with nitrogen. Plots of the cultivars ‘Grasslands Ruanui’ and ‘Ellett’ ryegrass were sown in April 1996. Half of each plot received nitrogen fertilizer (30 kg N/ha) after each grazing by dairy cows from September 1996 to May 1997 and from October 1997 to April 1998. Ryegrass tiller dynamics was monitored from September 1996 to March 1998. The proportion of reproductive tillers in the total tiller population was higher, on average, over the first flowering period (October 1996 to January …

Understanding The Etiology Of Taproot Decline Of Soybean Caused By Xylaria Necrophora, José E. Ortiz Solórzano

LSU Master's Theses

Taproot decline (TRD) of soybean is caused by Xylaria necrophora. However, the mechanisms by which it infects soybean and produces symptoms are unknown. Symptoms of TRD include foliar interveinal chlorosis and necrosis and root necrosis, yet X. necrophora appears to be restricted to the roots. While Xylaria species are predominantly wood decomposers, a few are pathogens. More importantly, they produce secondary metabolites (SMs) with multiple bioactivities, including phytotoxicity and antimicrobial activity. Preliminary experiments suggested that X. necrophora was producing SMs responsible for TRD symptoms. We evaluated cell-free culture filtrates (CFs) for phytotoxicity on soybeans, testing for changes in chlorophyll …

Tropical Legumes To Augment Forage Yield In The Eastern Caribbean, E. Valencia, M. B. Adjei

IGC Proceedings (1977-2023)

Little information is available on the contribution of tropical legumes to forage yield in the eastern Caribbean. This study assessed the effects of three grazing cycles (GC; 5, 10 and 15-wk) on seasonal dry matter (DM) yield of binary mixtures of the tropical legumes glycine (Neonotonia wightii) and desmanthus (Desmanthus virgatus) with “Bambatsi” (Panicum coloratum) and “Mottgrass” (Pennisetum purpureum Shum.). Plant responses were assessed by mob-grazing with sheep (12-24 hrs; to average stubble height of 15-cm) for each GC. Grazing cycles affected yield of both the legume and grass component (P< 0.05). At GC of 5-weeks, forage DM ranged from 1.5-2.0 Mg ha^-1 in …

Yield And Forage Quality In Alfalfa-Weeping Lovegrass Mixtures, H. Laborde, R. E. Brevedan, M. A. Varillas, M. N. Fioretti

IGC Proceedings (1977-2023)

Little is known about the relative performance of weeping lovegrass in mixtures with alfalfa. Our objective was to compare the productivity and forage quality of monocultures and binary mixtures of the species. Mixtures always gave higher yields than any of the monocultures and the highest was obtained in the mixture with the largest proportion of alfalfa. In the second year weeping lovegrass N concentration in the mixtures were higher than in monoculture. Weeping lovegrass did not affect the alfalfa N concentration. There was not differences in the NDF, for between these species.

Forage Quality Of Mixtures Of Bromus Wildenowii And B. Parodii Influenced By Nitrogen Fertilization Or Alfalfa Interseeding, S. Abarza, R. E. Brevedan, H. Laborde

IGC Proceedings (1977-2023)

Under good soil fertility conditions, Bromus wildenowii Kunth and Bromus parodii Covas et Itria are two high producing forage grasses. The objective of this study was to evaluate the effect of nitrogen fertilization or the association with alfalfa (Medicago sativa L) on yield and forage quality of mixtures of both grasses during the establishment year. Nitrogen fertilizer (300 kg ha^-1) was broadcasted in three 100 kg N dosis. Nitrogen fertilization or alfalfa intercropping did not increase dry matter yield. Tiller density and crude protein content of grass forage were increased by nitrogen application. Intercropped alfalfa increased N …

Intake And Yield Of Cynodon Nlemfuensis Alone And Associated With Leucaena Leucocephala Grazed By Sheep, J. G. Escobedo-Mex, Luis Ramírez-Avilés, Juan C. Ku-Vera

IGC Proceedings (1977-2023)

The objective of the present study was to determine dry matter intake (DMI) and the forage yield of green dry matter (GDM) of star grass (Cynodon nlemfuensis) alone and associated with Leucaena leucocephala cv. Perú grazed by sheep. The experimental treatments were: Systems T1) Star grass alone, and T2) Star grass + L. leucocephala. These treatments were evaluated during three seasons (i.e. Late-rainy, Dry and Rainy seasons). The availability of forage was lower (P < 0.0001) in T1, 2543 kg GDM/ha, than with T2, 3092 kg GDM/ha. Green dry matter in the rainy season was greater (P < 0.0001), with 3910 kg GDM/ha, than in the late-rainy and dry seasons, 2492 and 2052 kg GDM/ha, respectively. DMI was 5.9 and 7.6 g DM/kg of LW ^0.75/hour for the T1 and T2, respectively (P < 0.0001). DMI during the rainy season was lower (P < 0.01) than that of the dry and late-rainy seasons, 6.2, 6.4 and 7.5 g DM/kg LW^0.75/hour, respectively. The association C. nlemfuensis-L. leucocephala increased the availability of …

Allelopathy Of Panicum Maximum Jacq. Cultivars On Tree And Shrub Forage Legumes: Greenhouse Estimate, A. R. P. Almeida, T. J. D. Rodrigues

IGC Proceedings (1977-2023)

The available information about allelopathic effects of the genus Panicum on tropical forage legumes is scarce and inconclusive. Based on this fact this research was carried out, under greenhouse conditions to evaluate potential allelopathic effects of aqueous extracts (0,10 and 20%) of three cultivars of Panicum maximum Jacq. cv. Mombaça, cv. Aruana and cv. Tanzânia-1 on three forage legumes, Leucaena leucocephala (Lam.) de Wit. (leucaena), Cajanus cajan (L.) Millsp. cv. Kaki (pigeon pea) and Sesbania sesban (L.) Merr. (sesbania) seeking for mixed grasses and legumes pastures. The following characteristics were evaluated: emergence porcentage, speed of germination index, root density, dry …

Tillage Systems In The Establishment Of Pastures In Argentinian Subhumid Area, H. Pagliaricci, C. Saroff, A. Ohanian, T. Pereyra

IGC Proceedings (1977-2023)

The effect of three tillage systems on the number of plants produced and forage production of a pasture the first year of establishment was assessed in this experiment. The components of the pasture were alfalfa (Medicago sativa L.), tall fescue (Festuca arundinacea Shreb), orchard grass (Dactilys glomerata L), and prairie grass (Bromus unioloides). Treatments were three tillage systems: conventional tillage (CT), reduced tillage (RT), and direct sowing (DS). Sowing was performed with (NI) and without fertilizers (N0) in each treatment. A split-plot experimental design with two repetitions was used, with tillage being the main factor …

Correlation Between Yield Of Forage Legumes In Grass Mixtures And Accumulation Of Soil Mineral Nitrogen In Sweden, Magnus A. Halling, David Scholefield

IGC Proceedings (1977-2023)

Soil mineral N and DM yield of five forage legume species were investigated in field experiments at two sites in Sweden, established 1997. The species studied were: red clover (Trifolium pratense L.), lucerne (Medicago sativa L.), white clover (Trifolium repens L.), galega (Galega orientalis Lam.) and lotus (Lotus corniculatus L.), all grown in grass-legume mixed swards. No nitrogen was applied to the legumes. Results from two years of ley (1998 and 1999) are presented. Correlation was found between accumulated mineral N in the soil in the autumn and the total seasonal DM yield of the …

Introduction Of Forage Legumes Into Pastures Of Three Different Grasses, Maria T. Colozza, Joaquim C. Werner, Luciana Gerdes, E. A. Schamass, J. C. T. Freitas

IGC Proceedings (1977-2023)

It was evaluated the introduction of a mixture of calopo, galaxia, perennial soybean, guata and stylo broadcsted into marandu, setaria and tanzania half-plots already established in three cafeterias, each one located inside a paddock of each grass. The legumes were seeded in the end of the Spring (12/07/98), after the plots had been cut down and fertilized. The cafeterias were grazed intermittently by buffaloes maintained in the three paddocks. The occurrence of the five legume plants was avaluated by countings (#/m²) effected in the middle of Autumn, Winter and Spring of 1999 and Summer of 2000. Along with …

Allelopathy Of Panicum Maximum Jacq. Cultivars On Tree And Shrub Forage Legumes: Tolerance Index, A. R. P. Almeida, T. J. D. Rodrigues

IGC Proceedings (1977-2023)

The objective of this work was to evaluate the tolerance of three forage legumes (Leucaena leucocephala (Lam.) de Wit., Cajanus cajan (L.) Millsp. cv. Kaki and Sesbania sesban (L.) Merr.) to the allelopathic effects of three cultivars of Panicum maximum Jacq. (cv. Mombaça, cv. Aruana and cv. Tanzânia-1), under greenhouse conditions. The root and shoot tolerance indexes were calculated using the data of dry mass of roots and shoots of plants cultivated in pots and moistened with water or aqueous extracts (0,10 and 20%) of the cultivars of P. maximum. The results indicated that: a) the root tolerance …

Compatibility Of Kura Clover And Cool Season Grass Mixtures In Michigan, P. Jeranyama, R. H. Leep, T. Dietz

IGC Proceedings (1977-2023)

Kura clover (Trifolium ambiguum Bieb.) is an alternative forage legume for rotational grazing in cool-season grass mixtures. However, compatibility with cool-season grasses is unknown. Seven cool-season perennial grasses were seeded into Kura clover in a rotational grazing experiment. The objectives of this study were to evaluate botanical composition, forage yield and quality of binary mixtures of cool-season grass with Kura clover. Field studies were conducted on a Nester (fine sandy loam) soil at Lake City Experiment Station, Lake City, MI. Botanical compositions in the first year of the study heavily favored grasses (avg. 74%) and Kura clover accounted for …

Forage Legume Presence And Grazing Intensity Effect On Nitrogen Dynamics In Brachiaria Pastures In The South Of Bahia, Brazil, R. B. Cantarutti, R. Tarré, R. Macedo, C. De P. Rezende, J. M. Pereira, E. Ferreira, B. J. R. Alves, S. Urquiaga, R. M. Boddey

IGC Proceedings (1977-2023)

The objective of this study performed in the Atlantic forest region of the South of Bahia (Brazil) was to examine the influence of the presence of the forage legume Desmodium ovalifolium in pastures of Brachiaria humidicola on the nitrogen recycled through plant litter over stocking rates of 2, 3 and 4 head ha^-1. The results demonstrated that the presence of the D. ovalifolium in the pasture significantly increased the protein content of the associated Brachiaria grass, and the rate and quantity of N recycled through the litter pathway. While had no significant increase in animal weight gain due …

Production Of Orchard-Grass Cultivars (Dactylis Glomerata) In Mixtures With Alfalfa (Medicago Sativa), Under Grazing Conditions, R. A. Barbarossa, D. P. Miñón

IGC Proceedings (1977-2023)

In the Lower Valley of the Río Negro (northern Patagonia, Argentina), six binary mixtures of orchard-grass (Dactylis glomerata) cultivars (Porto, Currie, Filox, a Local ecotype, Pergamino El Cencerro MAG) and alfalfa (Medicago sativa) Monarca SP INTA, were tested under grazing and irrigation. Mixtures were evaluated during three growing seasons (96/97; 97/98 and 98/99). Total forage production of mixtures and botanical composition was measured (orchard-grass cultivars and alfalfa). Porto, Currie, Filox, Local and Cencerro cultivars reached similar yield, while Amba produced less forage (p< 0.05). Mixture yield showed no significant difference, except Porto + alfalfa, which was lower (p< 0.05). The grass was higher in spring (1^st grazing) of three growing seasons. Orchard-grass + alfalfa showed highest dry matter …

International Grassland Congress Outlook – A Historical Review And Future Expectations, L. R. Humphreys

IGC Proceedings (1977-2023)

Features of the history of the International Grassland Congress are mentioned. Aspects of a number of failed themes in grassland science are described with respect to molecular biology, intensive systems of ruminant production, carbohydrate use in plant growth, plant succession and range condition, and stocking method. Future expectations are focused on meeting a balance of objectives, maintaining reductionist science, taking new initiatives in plant improvement and in the development of animal production systems, and reducing barriers to international trade. The adoption of grassland science depends upon the growth of new learning, especially through cyclical interaction between scientists and farmers.

Production Potential Of South America Grasslands, G. E. Maraschin

IGC Proceedings (1977-2023)

Grasslands exist all over the world under a wide range of climates, soil types, topography conditions and seasonality. The South America grasslands cover a wide range of ecosystems and vegetaion types, going from desert areas to steppes, subhumid temperate, subtropical and tropical savannas embodying also portions of the tropical rain forest environment, and represent one of the Earth’s largest expanses of natural rangelands (Oesterheld et al., 1992). They represent developed ecosystems requiring acquaintance to accept sound agronomic and ecological activities. The diversity of vegetation determined by the latitudes 6^oN, down to the southern most tip of the continent …

Grassland Production And Management – Trends And Perspectives For The 21St Century, John Hodgson

IGC Proceedings (1977-2023)

The XIX International Congress is set in a time of unprecedented change, with increasing uncertainty about the long-term sustainability of established systems of land use. The major threats are the continuing rapid increase in the human population of the world, the pressure on land resources to meet food requirements, the effects of global warming on climate stability, and the consequence of these factors on land resource stability and food production potential. Overlying these threats is the impact of the global economy on land use policies.

Projections made at the XVIII International Grassland Congress in 1997 suggested that food production could …

Analysis And Countermeasure Of Unbalanced Ecology System Of Chinese Temperate Grassland, Xinshi Lu, Lin Ai

IGC Proceedings (1977-2023)

No abstract provided.

Natural Grassland Of China, Changcun Lin, Tingcheng Zhu

IGC Proceedings (1977-2023)

No abstract provided.