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Understanding Shoot And Root Development, C. Matthew, E. N. Van Loo, E. R. Thom, L. A. Dawson, D. A. Care

IGC Proceedings (1977-2023)

Shoot and root development of the grass tiller is presented as a series of events on the tiller axis. Leaf, tiller bud, true stem, and root development are successive events in the life cycle of a single phytomer and the tiller is a co-ordinated series of phytomers, successive phytomers being progressively more advanced than the previous phytomer. In reviewing the individual growth processes of leaf, tiller, true stem, and root formation, fundamental determinants of light and nutrient capture are examined and examples presented to illustrate the link between component processes, plant morphogenesis, and plant performance. An example of the application …

Ecophysiology Of Grasslands: Dynamic Aspects Of Forage Plant Populations In Grazed Swards, G. Lemaire

IGC Proceedings (1977-2023)

The aim of this paper is to review knowledge of the ecophysiological mechanisms influencing the dynamics of plant populations in grazed swards. Such an objective requires some definitions. Firstly, it is necessary to define “ecophysiology” as the study of the interactions between biological individuals (plants) with their own environment: how individuals perceive and react to any constraint and change of their environment, and how the functioning of plants as a population can modify their own environment. Such a definition implies a dynamic approach to pant population functioning as resulting from constant plant-plant interactions mediated by micro-environment modifications. In a grazed …

Bite Depth Penetration Patterns Of Dairy Cows Foraging On Complex Swards, W. M. Griffiths, J. Hodgson, G. C. Arnold

IGC Proceedings (1977-2023)

Sward height was the dominant cue used by dairy cattle to determine the depth of penetration on young vegetative swards. On more complex swards, bite depth penetration was controlled by variations in the depth of regrowth. Evidence showed that cattle grazed to the pseudostem:lamina interface, but sward height exerted a stronger effect on bite depth than pseudostem height. Modelling efforts to predict how the herbivore places bites in space in the vertical dimension across sward states are currently being restricted by the absence of detailed canopy structure descriptions. We argue that the contrast between strata is an important determinant of …

Nitrogen Response Efficiencies From Grazed Dairy Pastures Under Dry Conditions, Frank R. Mckenzie, Joseph L. Jacobs

IGC Proceedings (1977-2023)

Experiments were conducted within a long-term nitrogen (N) fertiliser experiment under grazing. The objective was to examine N response efficiencies (kg dry matter (DM)/kg N) and herbage crude protein (CP) content to fertiliser N applied under dry soil conditions (gravimetric soil moisture content of 17% at 10cm; soil field capacity = 38% and wilting point = 11%) during autumn (April 1999) and late spring (November 1999) in southeastern Australia. Visually, N treated plots were greener in colour than control (no N) plots. No differences were recorded in primary or residual DM yields, N response efficiencies, and pasture growth rates between …

Effect Of Defoliation Frequency And Planting Density On Yield And Nutritive Value Of Coursetia Ferruginea (Hbk) Lavin, H. J. Delgado Gómez, R. González Anciani, G. López, D. Urdaneta, L. Ramírez Avilés

IGC Proceedings (1977-2023)

The aim of the present study was to asses the influence of the frequency of defoliation and density of sowing on yield and nutritive value of Coursetia ferruginea. Three defoliation frequencies (6, 8 and 10 weeks) and three densities of planting (1 x 1 m, 1 x 1.5 m and 1 x 2 m) were evaluated. A randomized block design, in a split plot arrangement and four repetitions, was used. Frequency of defoliation has a strong significant (P< 0.01) effect on dry matter (DM) yield (13.6, 18.1 and 27.8 g DM/plant for 6, 8 and 10-week defoliation frequencies), plant height (63.5, 76.6 and 101.2 cm) and plant survival (71, 74 and 86%). Nutritive value was significantly (P< 0.05) affected by the frequency of defoliation. Mineral content was reduced as the defoliation interval increased. Density of planting did not affect (P> 0.05) any of the variables. It is concluded that, C. ferruginea is a forage shrub with potential to improve animal feed …

Interactions Between The Effects Of Nitrogen, And Phosphorus, Potassium And Sulphur On Grass Production, J. D. Morton, L. C. Smith

IGC Proceedings (1977-2023)

The interactions between rates of nitrogen (N) and rates of phosphorus (P), potassium (K) or sulphur (S) on yield of ryegrass dominant swards were measured with no return of mown clippings in Southland, New Zealand. In the second year of the trial, the yield response to 176 kg N ha^-1 compared with no N increased only slightly with increasing soil Olsen P from 8 to 91 µg g^-1 soil. At 352 and 704 kg N ha^-1 there was a large increase in the yield response (from 5 to 9.4 and 11 t DM ha^-1 respectively) up …

Application Of Near Infrared Reflectance Spectroscopy (Nirs) For Macronutrients Analysis In Alfalfa (Medicago Sativa L.), A. Morón, D. Cozzolino

IGC Proceedings (1977-2023)

Near infrared reflectance spectroscopy was used to assess the mineral composition of alfalfa (Medicago sativa L.) as a tool for nutritional diagnosis. One hundred and ninety four (n = 194) samples of alfalfa from different locations representing a wide range of soils were used. Samples were reflectance scanned in a NIRS 6500 (NIRSystems, USA) instrument. The coefficients of determination (R²) of the regression estimate of the concentration of nitrogen, calcium, phosphorus, potassium, magnesium and sulphur and the errors in cross validation (SECV) were 0.93 (SECV: 1.6), 0.95 (SECV: 1.3), 0.93 (SECV: 1.9), 0.88 (SECV: 2.8), 0.82 (SECV: …

Effect Of Liquid Cattle Manure Application On The Botanical Composition Forage Dry Yield And Soil Chemical Characteristics In Mixed Pastures, J. K. Lee, W. H. Kim, D. E. Shin, S. Seo, G. J. Choi, E. S. Chung, G. J. Park

IGC Proceedings (1977-2023)

Many farmers apply liquid cattle manure on grassland, often in excess of crop N requirement, resulting in groundwater contamination. Our experiment was carried out to determine the effect of liquid cattle manure application on the botanical composition, forage dry yield and soil chemical characteristics in mixed pastures at the forage experimental field, National Livestock Research Institute, RDA, Korea. Five treatments consisting of no fertilizer, chemical fertilizer (210kg N/ ha), liquid cattle manure (40, 60 and 80 ton N/ ha) were arranged in a randomized complete block design with three replicates. No fertilizer treatment consistently had lower botanical composition rate of …

Biological Interactions In Grassland Soils And Productivity, R. Cook, R. D. Bardgett, W. R. Eason, L. Skøt, K. J. Webb

IGC Proceedings (1977-2023)

This paper describes research on interactions between grassland plant species and soil microorganisms. Both parasitic and symbiotic microorganisms modify nutrient transfers between plants and soil. Experiments are described in which nematode infection of clover increased nitrogen transfer to companion ryegrass plants. Infection of clover enhanced activity of soil bacterial and fungal communities. Legume genotypes differing only in responses to symbionts (rhizobium and arbuscular mycorrhizal fungi) and pathogens are being developed for studies of gene expression during establishing and functional symbioses. Such plants can be used in experiments as defined perturbations that will provide information on the interactions and functions of …

Nitrogen Or Water Limitation To Grassland Growth During A Moderate Dry Season In The Humid Tropics, P. Cruz, M. Boval

IGC Proceedings (1977-2023)

The aim of this work was to compare the effects of nitrogen and water shortage on grassland production during a moderate dry season in a tropical humid environment. The results of two experiments carried out in Guadeloupe (FWI) have shown that during dry spells, the reduction in growth of natural grasslands based on Angleton grass (Dichantium aristatum) is more easily corrected by nitrogen fertiliser application than by irrigation. This shows that it is not the availability of water, but that of nitrogen, which is limiting the primary production of Angleton grass, stands. This result is less clear for …

Leaf Appearance Rate In Brachiaria Decumbens Grown In Nitrogen And Potassium Rates, M. D. C. Ferragine, F. A. Monteiro, S. C. Da Silva

IGC Proceedings (1977-2023)

A greenhouse experiment was carried out with Brachiaria decumbens Stapf. cv. Basilisk grown in nutrient solution. Five nitrogen rates (42; 140; 238; 336 and 434 mg/L) and three potassium rates (78; 234 and 390 mg/L) were studied in a factorial experiment, in a randomized complete block design, with four replications. Green leaf number was evaluated in six times in the first period of growth (27, 30, 33, 36, 39 and 42 days after transplanting) and nine times in the second period (45, 48, 51, 54, 57, 60, 63, 66 and 69 days after transplanting). Data was registered in three plants …

Morphogenesis And Defoliation Frequency Of Italian Ryegrass (Lolium Multiflorum) And Paspalum Urvillei In Lowland Under Three Levels Of P And K, Fernando L. F. De Quadros, A. G. S. Pigatto, D. G. Bandinelli, E. Marchezan, Marta G. Da Rocha

IGC Proceedings (1977-2023)

This trial was conducted to evaluate growth dynamics and defoliation frequency of Italian ryegrass (Lolium multiflorum) and Paspalum urvillei in a lowland area under three levels of P and K. Using randomization tests we observed that, in a general way, fertilizer treatments were not the determinant factors of leaf appearance and elongation rates for both species. Only the leaf appearance rate of Paspalum urvillei at 100 % of recommendation level and the elongation rate for Italian ryegrass, in the same treatment, was different. Probably other factors, like drainage, are contributing to these results. I. ryegrass phyllochron ranged from …

Effect Of Temperature On Phenology In Triple-Awned Grass (Stipagrostis Plumosa), Hossein Azarnivand, H. Dastmalchi

IGC Proceedings (1977-2023)

Phenology of triple-awned grass in different stages of vegetative growth, flowering and seed falling was investigated. Each phenological stage was related to minimum and maximum air and soil surface temperatures. Soil surface temperature was measured two times per day during different seasons. Climate data were obtained from the nearest weather station. The study was carried out in sand dunes of band-e-rig of Kashan in the central region of Iran. This species is important in terms of wind erosion control and livestock feeding in arid areas. The results showed that air temperatures ranged from –22 ^oC to 41.5 ^oC …

Response Of Mombaça Grass (Panicum Maximum Jacq.) To Nitrogen Doses And Clipping Frequency, Gustavo J. Braga, P. H. C. Luz, V. R. Herling, R. J. Schmidt, C. G. Lima

IGC Proceedings (1977-2023)

The present experiment had the objectives of determining the response of Mombaça grass (Panicum maximun Jacq.) to three levels of nitrogen fertilizer (0, 250, 500 kg/ha) and two clipping frequencies (28 and 42 days). Dry matter yield (DMY), density and the average weight of tillers and the mean stage count (MSC), value that represents the quantity of the plant phenological development were evaluated. Nitrogen levels affected DMY, with the 500 kg/ha of N resulting in highest yield, and highest MSC as well. The number of tillers responded positively until the 250 kg/ha level. The 42-day frequency gave higher numbers …

Seasonal Botanical Composition And Available Forage Of Natural Grasslands In The Southeastern Range Region Of Rio Grande Do Sul, Brazil, J. C. L. Reis, H. Alfaya, O. J. W. Siqueira, C. B. Farias Jr.

IGC Proceedings (1977-2023)

The objective of the study was to verify the influence of climatic seasons on botanical composition and on available dry matter of grasslands in the physiographic region known as Serra do Sudeste (Southeastern Range), RS, Brazil. The climate is Cfb according to Koëppen`s classification. The experiment was conducted in two natural grasslands submitted to two pre-experimental stocking rates [area 1: 0.65 AU ha^-1 (normal grazing); area 2: over 2.0 AU ha^-1 (overgrazing); AU: Animal Unit = 500kg live weight]. Stocking rates throughout the experimental period (June 1996–July 1997) were 0.4 and 0.65 AU ha^-1, over winter …

Effect Of Sowing Time On Phytomass Production During Early Growth Of Two Varieties Of Stylosanthes Guianensis (Aubl.) Sw., M. L.S. Paterniani, T. J. D. Rodrigues, G. T. Pereira, L. R. A. Rodrigues

IGC Proceedings (1977-2023)

The objective of this research was to determine the effect of two sowing times on phytomass production of two varieties of Stylosanthes guianensis (var. pauciflora and var. vulgaris). Two experimental periods were studied (1: January - May/1998 and 2: November/1998 - March/1999) using a completely randomized factorial design 2 x 2 x 14 (two periods, two varieties and fourteen ages of evaluation), with four replications. The results showed a difference between the periods concerning the growth and development of Stylosanthes, and that period 2 was the most favourable to this forage plant. There was, also, different adaptability between …

Effects Of Photoperiod, Low Temperature And N Nutrition On Vsp Accumulation In Taproot Of Alfalfa, J. C. Avice, C. Noquet, A. Ourry, J. J. Volenec

IGC Proceedings (1977-2023)

In Medicago sativa L., vegetative storage protein (VSP), specifically accumulated in taproot, are strongly involved in nitrogen storage. How the accumulation of such VSPs is regulated remains largely unknown. Experiments were designed with non-nodulated alfalfa to determine if length of the photoperiod, a decrease of temperature, or high availability of mineral nitrogen may induce the accumulation of VSPs. ¹⁵N labelling was used to quantify nitrogen uptake and its further relative translocation within the plant while VSPs accumulation was analysed by ELISA quantification. Results showed that environmental factors such as shortening daylength or low temperature changed biomass allocation within the …

Tillering Dynamics Of Panicum Maximum Jacq. Cv. Tanzania-1 After Grazing, Rodrigo A. Barbosa, Domicio Nascimento Jr., Valéria P. B. Euclides, A. J. Regazzi, D. M. Fonseca

IGC Proceedings (1977-2023)

Tillering dynamics and tiller dry matter weight from Tanzania grass (Panicum maximum cv. Tanzania-1) were evaluated in two post-grazing stubbles (High Post-grazing Stubble – HPS-3.6 t of DM/ha and Low Post-grazing Stubble – LPS-2.3 t of DM/ha). There was no difference between post-grazing stubbles for decapitated axillary and basal remainder and new axillary tillers. The LPS presented greater number of new basal tillers. The rate of appearance of new basal and axillary tillers decreased with time after grazing. There were differences between the treatments on tiller dry matter weight, and greater values were found in the high post-graze stubble.

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 …

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.

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 …

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 …

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 …

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 …

Finding New Strategies To Rehabilitate Grasslands In Western China, David R. Kemp, Z. B. Nan, J. P. Wu, J. F. Yun, Z. Xu

IGC Proceedings (1977-2023)

No abstract provided.

Slope Aspect Has Effects On Belowground Biomass And Root Length Of Semi‐Arid Hilly Steppe, Xiaoying Gong, Shan Lin, Qingmin Pan, Holger Brueck, Klaus Dittert, Friedhelm Taube

IGC Proceedings (1977-2023)

No abstract provided.