Digital Commons Network^™

Effects Of Different Levels Of Energy On Growth Of Grazing And Drylot Fed Holstein Heifers, L. P. Novaes, C. E. Polan

IGC Proceedings (1977-2023)

Growth of Holstein heifers were studied to evaluate the combination of a drylot phase followed by feeding energy for pasture supplementation during the grazing season of 1988. Heifers grazed a grass-legume mixture in six paddocks of 1.5 ha each. After drylot, animals were equally allotted to pasture and none or 2.0 kg/d of corn were fed in addition to grazing in a changeover design with repeated measurements. Heifers were fed a high (HE) or low energy (LE) diets in confinement and daily gains were 1190 (HE) and 990 g/day (LE) which were different. On pasture, corn supplementation did not enhance …

Nitrogen Fertilization In Paspalum Dilatatum, Poir: Herbage Production, Nutritive Value And Structural Characteristics, G. Acosta, V. A. Deregibus

IGC Proceedings (1977-2023)

It was studied the effect of nitrogen application on structural changes and quantity and quality characteristics of a Paspalum dilatatum Poir sward, under field conditions during two growing seasons. The nitrogen (N) rates were 0 and 440 kg ha^-1 applied during the first year in split applications. The nitrogen fertilization increased leaf, stem and cumulative total dry matter yield, plant height, tiller density, cover ground and leaf crude protein yield.

Growth Responses Of Acacia Angustissima To Vesicular-Arbuscular Mycorrhizal Inoculation, N. Lucena Costa, Valdinei T. Paulino, T. S. Paulino

IGC Proceedings (1977-2023)

The response of Acacia angustissima to VAM species (Acaulospora laevis, A. muricata, Entrophosphora colombiana, Glomus mosseae, G. fasciculatum, G. macrocarpum, G. etunicatum, Gigaspora margarita, G. gigantea and Scutellospora heterogama) was evaluated under greenhouse conditions, in a P-deficient clayey Oxisol of pH 5.5. The soil was sterilized at 110^oC for one hour each day for three days and reinoculated with a soil microbial suspension free of mycorrhizal fungi spores. The several VAM fungi were effective in increasing DM yield, nodulation, and N and P uptake of A. angustissima plants. The most efficient species were E. colombiana, A. …

Impact Of Overseeding Cool-Season Annual Forages On Spring Regrowth Of Tifton 85 Bermudagrass, Ricardo A. Reis, Lynn E. Sollenberger, D. Urbano

IGC Proceedings (1977-2023)

Field observations have shown stand reduction and slow spring regrowth of Tifton 85 bermudagrass (Cynodon spp.) pastures overseeded with temperate forages for grazing during the cool season. This experiment compared the effect of cool-season management programs, including overseeding and use of different grazing treatments, on productivity of Tifton 85 the following warm season. There were seven treatments: four were bermudagrass overseeded with a cool-season annual forage mixture (two grasses and two legumes) and grazed differentially, and three were bermudagrass controls with differences in amount of residual stubble remaining at beginning of autumn. There was only a slight delay in …

Influence Of Grazing Frequency On Biomass Production Using Several Selected Tropical Grasses, P. Mislevy, F. G. Martin, F. M. Pate, N. F. G. Rethman

IGC Proceedings (1977-2023)

To provide commercial growers with forage grasses that produce well throughout the year, there is a constant need for screening and testing new germplasm. Two rhodesgrasses (Chloris gayana cv. Rhods and Callide), four stargrasses (Cynodon nlemfuensis Vanderyst var. nlemfuensis cv. Florona, Zimbabwe, Okeechobee, and Rhodesian No. 2), one bermudagrass (C. dactylon var. dactylon cv. Jiggs), and one creeping signalgrass (Brachiaria humidicola CIAT 6369) were tested under a mob-grazing system. Dry biomass yield increased linearly as grazing frequency (GF) was delayed from 2 to 7 weeks. The cultivars, Florona, Zimbabwe and Okeechobee stargrasses and Jiggs bermudagrass, yielded …

Nutritive Value Of Double Cropped Corn For Ruminant Production, D. Vaz Martins, A. Fassio

IGC Proceedings (1977-2023)

The viability of double cropping corn (Zea mays L.) in Uruguay, germplasm combination, dry matter yield and nutritive value were evaluated. An early (E) maturing hybrid, an early to medium (E-M) one and an E-M variety were planted as spring crops. One E-M hybrid, one medium to late (M-L) hybrid and a late (L) variety were planted as a second crop. PVC laboratory scale silo of the spring crop and the whole plant of the summer crop were chemically analyzed. The nutritive value of the silages were related to plant maturity stage. No differences were detected in nutritive value among …

Identification Of Bacterial Wilt (Erwinia Tracheiphila) Resistances In Usda Melon Collection, Bimala Acharya, Lucas Mackasmiel, Ali Taheri, Christine A. Ondzighi-Assoume, Yiqun Weng, C. Korsi Dumenyo

Agricultural and Environmental Sciences Faculty Research

Bacterial wilt (BW) caused by the Gram-negative bacterium, Erwinia tracheiphila (Et.), is an important disease in melon (Cucumis melo L.). BW-resistant commercial melon varieties are not widely available. There are also no effective pathogen-based disease management strategies as BW-infected plants ultimately die. The purpose of this study is to identify BW-resistant melon accessions in the United States Department of Agriculture (USDA) collection. We tested 118 melon accessions in two inoculation trials under controlled environments. Four-week-old seedlings of test materials were mechanically inoculated with the fluorescently (GFP) labeled or unlabeled E. tracheiphila strain, Hca1-5N. We recorded the number of days to …

Adapting Tropical Forages To Low-Fertility Soils, Idupulapati M. Rao

IGC Proceedings (1977-2023)

Tropical forages growing in low-fertility acid soils usually increase the amount of dry matter partitioned to roots at the expense of shoot growth, but substantially different adaptive attributes to such soils have been found, both between and within species. By possessing the C₄ pathway of photosynthesis, grasses are more efficient than legumes in using N, Ca, and P, whereas legume roots are more efficient in extracting nutrients from low-fertility soils. Phosphorus uptake efficiency (mg of P uptake in shoot biomass per unit root length) of the legume Arachis pintoi is several times higher than that of the grass Brachiaria …

Adaptation Of Forage Species To Drought, D. J. Barker, J. R. Caradus

IGC Proceedings (1977-2023)

Variability in rainfall is the single greatest cause of variation in forage production for a given site. Current climate scenarios predict future annual rainfall to decrease at some geographic regions. The intensity of future rainfall is also predicted to increase at other regions, with the expectation of greater variability in soil moisture. The adaptation of forage species to drought is an issue that is likely to remain with us into the future.

Precise definitions are critical to water relations work, and imprecise use of terms has complicated comparisons of some studies on plant response to drought. Drought is a purely …

Grassland Plant Diseases: Management And Control, S. Chakraborty

IGC Proceedings (1977-2023)

Grasslands cover 40% of the earth’s surface and support animal-based industries; maintain soil cover, watersheds and biodiversity; sequester atmospheric carbon for storage in the soil; and provide tourism and leisure income. Diseases continue to decrease herbage and seed yield and reduce nutritive value and palatability of grasslands to impact on animal health and productivity but realistic data on loss are hard to find. Although principles of disease management remain the same, strategies used in crop protection can not be directly applied to grasslands due to differences in heterogeneity, population size, density and spatial distribution and population continuity. Low per hectare …

Micronutrients In Grassland Production, U. C. Gupta, F. A. Monteiro, J. C. Werner

IGC Proceedings (1977-2023)

Micronutrients, also known as trace minerals, which chiefly include boron (B), molybdenum (Mo), copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe), are required in extremely small quantities by crops and livestock. Their name, however, is not meant to imply their role is minor. Their lack, e.g., can cause serious crop production problems in forages and health disorders in livestock. This presentation includes the response of forage legumes and grasses to micronutrients, their deficiency and sufficiency levels in forages and their sufficiency levels in livestock. Forage legumes are more responsive to micronutrients, particularly B and Mo, than grasses. There are …

Novel Grasses And Legumes Germplam: Advances And Perspectives For Tropical Zones, E. A. Pizarro

IGC Proceedings (1977-2023)

It has been the aim, in the present article, to bring together as much as possible scientific evidence and experience in new available germplasm for tropical zones.

The economic importance of the Brachiaria, Paspalum and Pennisetum grasses is well established. New germplasm has become available since 1980. This paper reviews evaluations of Brachiaria accessions in humid lowlands and savannas of tropical America. The selection criteria need to be revised. Also, it is necessary to expose the new material as early as possible to farmers in order to select new germplasm with high chances of adoption.

Within the genus Paspalum …

Temperate Forage Grass-Legume Mixtures: Advances And Perspectives, A. S. Laidlaw, N. Teuber

IGC Proceedings (1977-2023)

The paper summarises some of the advances which have been made a) in increasing understanding of the grass-legume association, especially grass-white clover, so that the association can be more predictably exploited and b) in overcoming limitations in the use of such mixtures. The contribution which forage legumes make to the N economy of mixtures is reviewed with estimates approaching 400 kg N ha^-1 for some. Uptake by grass of legume- derived N (N transfer) reduces soil mineral N levels and increases the proportion of fixed N in the total legume N relative to legume monoculture. Although N transfer also …

Assessing The Effect Of N And P Supply On Dry Matter Yield Of Three Tropical Grasses, O. Topall, C. Jouany, M. Duru, P. Cruz

IGC Proceedings (1977-2023)

The objectives are to study the effects of N and P supply and their interaction, on herbage dry matter yield and nutrient status of three tropical grasses. In order to estimate direct and indirect effects of P supply we express above-ground dry matter production as a function of the herbage nutrient status obtained from plant analysis. Results show that in absence of N, the significant increase in P nutrition status has only moderate consequences on herbage production and suggest that both N and P are limitant for herbage growth. P fertilization results in significant increase in dry matter yield only …

Sources And Rates Of Phosphorus In Improving Degraded Pasture In Brazilian West Amazon, Valdinei T. Paulino, N. L. Costa, C. R. Townsend, J. A. Magalhães, R. G. A. Periera

IGC Proceedings (1977-2023)

The effects of phosphorus sources (triple superphosphate – TSP, single superphosphate – SSP and partially acidulated rock phosphate – PARP) and rates (0, 50 and 100 kg/ha of P₂O₅ on dry matter (DM) yields and chemical composition of a degraded Brachiaria brizantha cv. Marandu pasture were evaluated in a cutting trial. Phosphorus fertilization, irrespective of sources and rates, showed an effective agronomic technique for pasture recuperation. The grass DM yields and potassium contents were significantly improved by phosphorus application, while weed DM yields were depressed. Irrespective of sources and rates, crude protein, phosphorus, and calcium contents were …

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 …

Effect Of Volatile Compounds Produced By Selected Bacterial Endophytes In Promoting Plant Growth, Asha Maheshwari, Margaret T. Mmbaga, Bandana Bhusal, Christine A. Ondzighi-Assoume

Agricultural and Environmental Sciences Faculty Research

Bacterial endophytes selected for their capability to suppress diverse fungal pathogens in vitro and in greenhouse studies have been shown to promote plant growth. The effect of volatile compounds emitted by selected bacteria on plant growth in Arabidopsis thaliana, tomato (Solanum lycopersicum), sweet pepper (Capsicum annuum), and cucumbers (Cucumis sativus) was evaluated on container-grown plants nested above bacterial cultures, with roots exposed to the volatiles without direct contact between bacterial cells and the plant roots. Significant increases in plant growth were observed in plant height, root length, leaf size, fresh weight, and chlorophyll content in all plants tested. Although diverse …

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 …