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Articles 481 - 510 of 14814

Full-Text Articles in Earth Sciences

Cattle Preference And Plant Selection Within A Hybrid Grass, P O. Currie, R S. White, K H. Asay Jun 2026

Cattle Preference And Plant Selection Within A Hybrid Grass, P O. Currie, R S. White, K H. Asay

IGC Proceedings (1977-2023)

Recent development of hybrid forage grasses shows promise for advancing grassland agriculture. Previous selections within these hybrids have been based on morphological, reproductive, and adaptive attributes with only limited testing of animal ac• ceptability. Testing of animal preference and selectivity was the primary purpose of the present study. Yearling cattle were tamed and observed for their selectivity in grazing individual plants and genetic lines of F6 crosses between quackgrass (Agropyron repens) x bluebunch wheatgrass (Agropyron spicatum). Animals showed definite preference for individual plants within genetic lines and for different genetic lines. Different animals frequently preferred the same plant or lines …

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Combination Range-Pasture Management In South Florida For A Low-Energy Grassland Program, L L. Yarlett Jun 2026

Combination Range-Pasture Management In South Florida For A Low-Energy Grassland Program, L L. Yarlett

IGC Proceedings (1977-2023)

The semitropical environment of south Florida is favorable for coordinated management of a wide variety of native grass species and improved pasture forages. The decade of the 1980s will emphasize change from forage programs of high energy utilization to those with a low requirement of fossil fuels. For 4 decades, grassland management in south Florida has been primarily pasture establishment created from the rangeland resource. The establishment and management required substantial inputs of fossil fuel. Use and management of rangeland was largely neglected. Ecological concepts as a basis for managing semitropical ranges were not accepted. In recent years practical programs …

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Forage Intake Of Cattle As Affected By Grazing Pressure, C D. Allison, M M. Kothmann, L R. Rittenhouse Jun 2026

Forage Intake Of Cattle As Affected By Grazing Pressure, C D. Allison, M M. Kothmann, L R. Rittenhouse

IGC Proceedings (1977-2023)

A series of trials was conducted in 1977 to determine the effect of level of grazing pressure on organic-matter intake and the relationship between intake and forage disappearance. Levels of grazing pressure studied were 10, 20, 40, and 50 kg forage allowed/animal unit/day (kg/AU/day) for 14-day trials in April, July, and September. A standing crop of forage was measured before, in the middle of, and immediately after each trial. Organic-matter intake was estimated by the fecal output: indigestibility ratio technique. Organic-matter intake was highest in April; cattle also consumed Dlore forage in September than in July. The combination of forage …

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Effect Of Herbage Mass And Allowance Upon Herbage Intake By Grazing Dairy Cows, J.A C. Meijs Jun 2026

Effect Of Herbage Mass And Allowance Upon Herbage Intake By Grazing Dairy Cows, J.A C. Meijs

IGC Proceedings (1977-2023)

An adequate supply of nutrients for grazing animals depends on the intake and nutritive value of herbage. Little information is available on factors affecting herbage intake of grazing cows, particularly for grazing systems that do not involve daily change of animals to a new pasture. Our objectives were to determine the effects of variation in herbage mass ( due to variation in stage of maturity) and of herbage allowance on herbage intake by grazing dairy cows and on efficiency of consumption (herbage con­sumed as a proportion of herbage accumulated). From 1976 to 1979 the herbage intake oflactating cows was determined …

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Relation Of Animal Production To Stocking Rate On Cultivated Pastures In Cerrados Areas Of Brazil, C J. Escuder Jun 2026

Relation Of Animal Production To Stocking Rate On Cultivated Pastures In Cerrados Areas Of Brazil, C J. Escuder

IGC Proceedings (1977-2023)

The relationships among stocking rate, gain/animal, and gain/ha were compared on six grazed pastures. The experiment was established on an oxisol acrustox in Brazil. The pasture consisted of (1) jaraguagrass (J); (2) jaraguagrass plus legumes (J + L); (3) molassesgrass (M); (4) molassesgrass plus legumes (M + L); (5) pangolagrass (P); (6) Pangolagrass plus legumes (P + L); (7) mixture of grasses (jaragua, molasses, and pangola) plus legumes (JMP + L). Pasture of pangolagrass alone was discarded because of poor establishment. Four stocking rates were applied on each pasture, from 1.0 to 3.4 animals/ha. For all pastures, gains/animal decreased linearly …

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Evaluation Of Forages Ensiled In Concrete Stave And Oxygen-Limiting Silos, J O'Leary, R W. Hemken, L S. Bull Jun 2026

Evaluation Of Forages Ensiled In Concrete Stave And Oxygen-Limiting Silos, J O'Leary, R W. Hemken, L S. Bull

IGC Proceedings (1977-2023)

This study evaluated corn silages stored in concrete stave and oxygen-limiting silos during 1978-1980. Factors considered in­cluded the effect of environmental conditions in each silo on silage stability and feeding value. Milk production was evaluated using Holstein cows, intake studies used Holstein heifers or steers. Weekly measurements of intake, milk production, silage temperature, pH, and yeast and mold content were made for each silage. Aerobic stability was determined monthly. Silo type had no effect on intake or milk production. Silage temperatures from the oxygen-limiting silo were higher, and the silage was less stable than that from concrete stave silos. No …

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Round Baling From Field Practices Through Storage And Feeding, W L. Kjelgaard, P M. Anderson, L D. Hoffman, L L. Wilson, H W. Harpster Jun 2026

Round Baling From Field Practices Through Storage And Feeding, W L. Kjelgaard, P M. Anderson, L D. Hoffman, L L. Wilson, H W. Harpster

IGC Proceedings (1977-2023)

A model analysis compared labor and fuel requirements for round and rectangular bale systems. Round baling reduced harvesting, transport, and handling labor by one-half but increased fuel use by a factor of 1.6. When data from field studies of all dry matter (DM) losses were included, round baling required 80 % as much labor and 200 % as much fuel as did rectangular bal­ing. Baling losses for round balers and stackers averaged 10 % compared with 3 % for rectangular balers. ·Dry-matter losses from mowing through feeding of field-cured round bales, including 6 months of outdoor storage, totaled 41 % …

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Harvesting And Processing Effects On Alfalfa Protein Utilization By Ruminants, R Britton, D Rock, T Klopfenstein, J Ward, J Merrill Jun 2026

Harvesting And Processing Effects On Alfalfa Protein Utilization By Ruminants, R Britton, D Rock, T Klopfenstein, J Ward, J Merrill

IGC Proceedings (1977-2023)

Alfalfa (Medicago sativa) is an efficient and important means of producing supplemental protein for ruminants. This research was undertaken to characterize the value of alfalfa protein for ruminants and to show how the protein is affected by different harvesting or processing regimens. The effects of maturity (prebloom, one-tenth, one half, and full bloom) and processing method (freeze dried [FD], sun cured [SC], and oven heated [HJ), on percentage of nitrogen (N), acid detergent insoluble N (ADIN), in-vitro rumen ammonia release (NH3), and in-situ rumen protein degradation, using dacron bags (BAG), were studied on irrigated alfalfa harvested over 2 years. …

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Comparison Of Conservation Methods Under Controlled Practical Conditions, H Honig, K Rohr, E Zimmer Jun 2026

Comparison Of Conservation Methods Under Controlled Practical Conditions, H Honig, K Rohr, E Zimmer

IGC Proceedings (1977-2023)

The most common forage conservation methods (direct-cut and low-moisture silage, barn,dried hay, and dehydration) have been compared under practical, but strictly controlled, conditions to determine their relative value for meeting the increasing demands of high-yielding ruminants. A grass mixture was used as forage, at different stages of maturity in different ex­periments. Parameters determined were changes of nutrient content; losses of DM and net energy; and, in three experiments, forage intake by dairy cows. From the results of the experiments, the following conclusions could be drawn: (1) roughage quality is influenced more by cuttng time than by preservation methods; (2) low-moisture …

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Wet Fractionation Of Alfalfa: A Direct Forage-Harvesting System, M Collins, R G. Koegel, N A. Jorgensen, H W. Ream Jun 2026

Wet Fractionation Of Alfalfa: A Direct Forage-Harvesting System, M Collins, R G. Koegel, N A. Jorgensen, H W. Ream

IGC Proceedings (1977-2023)

In this syst􀀇m, termed wet fractionation, fresh forage is macerated and pressed to remove approximately 50 % of the moisture. The result is a forage product containing 32 %-38 % dry matter (DM) that can be ensiled directly. In addition, the protein con­tained in the plant juice can be coagulated and removed. The remaining deproteinized juice contains large quantities of mineral nutrients that can be returned to the soil. This process has several potential advantages: (1) less weather-dependent harvesting, which minimizes harvest losses; (2) reduced harvesting time; (3) reduced fertilizer requirements; and (4) ability to harvest protein from land unsuited …

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Hastening Hay Drying, J W. Thomas, T R. Johnson, M A. Wieghart, C M. Hansen, M B. Tesar, Z Helsel Jun 2026

Hastening Hay Drying, J W. Thomas, T R. Johnson, M A. Wieghart, C M. Hansen, M B. Tesar, Z Helsel

IGC Proceedings (1977-2023)

The objectives of these studies were to increase the drying rate of cut alfalfa (Medicago sativa) by treating with chemical solu­tions and to examine factors that influence drying. Time to dry and drying rate of cut alfalfa were studied under laboratory and field conditions. Treatment consisted of spraying the cut alfalfa with methyl esters of long-chain fatty acids, an emulsifier alone, or a combination of an emulsifier and a potassium carbonate solution. Alfalfa sprayed with solutions of each chemical under specified conditions increased drying rate and decreased drying time to 60% or 75 % dry matter (DM) or …

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Alternative Treatment Systems To Increase The Drying Rates Of Green Forage Crops, W E. Klinner, O D. Hale Jun 2026

Alternative Treatment Systems To Increase The Drying Rates Of Green Forage Crops, W E. Klinner, O D. Hale

IGC Proceedings (1977-2023)

Forms of conditioning treatment are being developed that aim to minimize the barrier effect of the crop cuticle without sacrificing too much of the structural strength of the herbage. Effective surface abrasion and favorable windrow structure can be achieved with steel-spoked rotors, which are now beginning to be offered commercially. More recently, plastic brushes have been developed because the higher population density and yielding ability of the crop-engaging elements, plus the absence of metal components, appeared to offer additional advantages. Four different brush conditioner systems have been evaluated in the laboratory and in replicated field experiments. Tufted brushes using trilobar …

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Effects Of Microwave Treatment On Drying And Respiration In Cut Alfalfa, S A. Seif, D A. Holt, V L. Lechtenberg, R J. Vetter Jun 2026

Effects Of Microwave Treatment On Drying And Respiration In Cut Alfalfa, S A. Seif, D A. Holt, V L. Lechtenberg, R J. Vetter

IGC Proceedings (1977-2023)

After forage crops are cut mechanically, they usually undergo some degree of natural drying before being stored or further processed. During early stages of drying, plant respiration continues. Treatments or management practices that hasten drying and reduce postharvest respiration are desirable, because they minimize quantity and quality losses. Our objective was to determine the effects of brief microwave treatment on subsequent natural drying rate and respiration of alfalfa (Medicago sativa L. ). Duplicate samples of field grown Apollo alfalfa were subjected to focused microwave energy (2,450 MHz) generated at 0.25, 0.50, or 1.0 kilowatt of power for 3, 6, …

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Effect Of Formic Acid- Formaldehyde Treatments On The Nitrogenous Constituents In Annual Ryegrass Silage, M L. Fishman, F Mchan, D Burdick Jun 2026

Effect Of Formic Acid- Formaldehyde Treatments On The Nitrogenous Constituents In Annual Ryegrass Silage, M L. Fishman, F Mchan, D Burdick

IGC Proceedings (1977-2023)

Prevention of proteolysis during ensiling is important in preserving the nutritive value of silage. Hence, the mechanism by which silage protein is protected against degradation was studied in wilted annual ryegrass (Lolium multiflorium Lam.) silage pretreated with formic acid, formaldehyde, and a formic acid-formaldehyde mixture. Raw-wilted ryegrass, control ryegrass silage, and treated ryegrass silage were extracted and fractionated under conditions previously found to maximize yield of nitrogenous constituents and minimize proteolysis during the extraction of fresh grass. Extractions were by boric acid-borate buffer at pH 8.0 with and without detergent (1 % sodium dodecyl sulfate). Sodium metabisulfite, an antioxidant, was …

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Addition Of Lactobacillus Sp. To Aid The Fermentation Of Alfalfa, Corn, Sorghum, And Wheat Forages, N J. Moon, L O. Ely Jun 2026

Addition Of Lactobacillus Sp. To Aid The Fermentation Of Alfalfa, Corn, Sorghum, And Wheat Forages, N J. Moon, L O. Ely

IGC Proceedings (1977-2023)

As preservation of forage by ensiling has increased, so has the use of additives to enhance acid fermentation. Many of the fermentation aids currently on the market contain microflora to insure a lactic acid fermentation. The objectives of this study were to characterize the basic patterns of fermentation in a variety of crops and to evaluate the effects of adding selected microflora to forages to enhance the fermentation. Four crops were ensiled in each of three seasons. Alfalfa was harvested at 20 %-40 % bloom, second cut; wheat was cut in the early dough stage; corn was cut in the …

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Interrelationships Between Pattern Of Fermentation During Ensilage And Initial Crop Composition, J M. Wilkinson, P F. Chapman, R J. Wilkins, R F. Wilson Jun 2026

Interrelationships Between Pattern Of Fermentation During Ensilage And Initial Crop Composition, J M. Wilkinson, P F. Chapman, R J. Wilkins, R F. Wilson

IGC Proceedings (1977-2023)

Relationships between crop composition and silage composition were examined for 231 silages made at the Grassland Research Institute from 1968 to 1978 without additives. A test was made of the model of Weissbach et al. (1974) in which silage characteristics were related to the percentage of dry matter in the crop (OM) and the ratio of sugar (Z) to buffering capacity (PK). Although these factors accounted for significant variance, the percentage accounted for was low at 36 % for lactic acid (percentage of total acids), 26 % for Flieg's score, 22 % for ammonia N (percentage of total N), and …

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Effect Of Delayed Sealing During Ensiling On Fermentation And Dry-Matter Loss, N Takano, Y Masaoka, T Manda Jun 2026

Effect Of Delayed Sealing During Ensiling On Fermentation And Dry-Matter Loss, N Takano, Y Masaoka, T Manda

IGC Proceedings (1977-2023)

Two experiments were carried out from 1976 to 1980 to ascertain the effect of delayed sealing of silo on fermentation, dry· matter (DM) loss, digestibility, and silage intake. The effect of delayed sealing (up to 72 hours) of grass and corn silage was tested in laboratory silos on fermentation quality with storage temperatures at 15°C and 30°C, moisture content from 49% to 85 % , water-soluble carbohydrate (WSC) content ranging from 11.1 % to 17.5%, and with and without an addition of 0.25% formic acid. In all cases, delayed sealing resulted in poor-quality silage with high pH values and low …

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Improving Hay Quality By Ammoniation, K J. Moore, V L. Lechtenberg, K S. Hendrix, J M. Hertel Jun 2026

Improving Hay Quality By Ammoniation, K J. Moore, V L. Lechtenberg, K S. Hendrix, J M. Hertel

IGC Proceedings (1977-2023)

Experiments were conducted to determine the effect of hay ammoniation on hay consumption and weight gain by steers when the hay was fed unsupplemented and supplemented with energy and protein. Mature orchardgrass (Dacrylis glomerata L.) hay was baled in early June 1979 and treated with anhydrous ammonia at 30 g/kg of hay. Seven weeks after treatment the hay was uncovered and allowed to aerate for 3 days. It was then fed to weanling steer calves weighing approximately 225 kg each. Similar hay baled from the same field but not ammoniated was fed to separate groups of steers. Both the treated …

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Evaluations Of Low-Quality Roughages And Fibrous Cereal Grains Treated With Various Chemicals, G C. Fahey Jr, L L. Berger, M I. Mora, P J. Van Der Aar Jun 2026

Evaluations Of Low-Quality Roughages And Fibrous Cereal Grains Treated With Various Chemicals, G C. Fahey Jr, L L. Berger, M I. Mora, P J. Van Der Aar

IGC Proceedings (1977-2023)

Large improvements in the feeding value of low-quality roughages have resulted from treatment of them with various chemicals. Chemical treatment of grains may also be a potentially useful practice. The research reported here was designed (1) to determine how Chelating Metal Caustic Swelling (CMCS), a nontoxic, alkaline, aqueous reagent, compares with sodium hydroxide (NaOH) in enhancing in-vitro cellulose digestion (IVCD) of cornstalks (CS) (Zea mays) and soybean residues (SBR) (G!),cine max.), and (2) to evaluate the effects of NaOH and CMCS treatments of fibrous grains using in-situ techniques. CMCS or 7.5% NaOH solutions were added to CS or SBR at …

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Effect Of Solvent Treatments On Intake And Digestibility Of Corn Stover, D M. Schaefer, M R. Ladisch, C H. Noller, V L. Lechtenberg Jun 2026

Effect Of Solvent Treatments On Intake And Digestibility Of Corn Stover, D M. Schaefer, M R. Ladisch, C H. Noller, V L. Lechtenberg

IGC Proceedings (1977-2023)

Treatment of crop residues with low levels of sodium hydroxide has been shown to improve organic-matter digestibility and animal performance. One objective of these experiments was to evaluate the effects of three treatments -water, sodium hydrox­ide, and chelating metal cellulose-swelling solution-on solubilization of cell-wall components in corn (Zea m£rys) stover. The two latter treatments were balanced for level of sodium hydroxide application, which was .3 .2 % of stover dry matter. The second objective was to determine the effects of these treatments on in-vitro and in-vivo digestibility as well as on consumption of corn stover. Twelve growing ram lambs were …

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Factors Causing Greater In-Vitro Than In-Vivo Digestibility Of Sodium Hydroxide - Treated Roughages, L L. Berger, T J. Klopfenstein, R A. Britton Jun 2026

Factors Causing Greater In-Vitro Than In-Vivo Digestibility Of Sodium Hydroxide - Treated Roughages, L L. Berger, T J. Klopfenstein, R A. Britton

IGC Proceedings (1977-2023)

Research on sodium hydroxide (NaOH) treatment oflow-quality roughages generally indicates that in-vivo digestion is lower than in-vitro digestion. The purpose of this research was to identify factors that may cause less of the potentially digestible fiber to be digested in vivo than in vitro. Corn (Zea mays) cobs were raised to 60% moisture and treated to contain 0%, 2.5%, 5.0%, 7.5 % , and 10.0% NaOH. Lambs were fed diets containing 80% cobs and 20% supplement, giving a complete mixed diet con· taining 0%, 2.0%, 4.0%, 6.0%, and 8.0% NaOH. Five abomasally cannulated lambs were assigned to a 5 x …

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Relationship Between Silage Quality And 15 N-Nitrate Reduction During Ensilage, K Ataku, M Horiguchi, T Matsumoto Jun 2026

Relationship Between Silage Quality And 15 N-Nitrate Reduction During Ensilage, K Ataku, M Horiguchi, T Matsumoto

IGC Proceedings (1977-2023)

Nitrate in forage has been proven to occasionally poison ruminants. Our recent studies, however, have shown that a high con­centration of nitrate inhibits butyric acid fermentation to the advantage of the silage quality. This work was undertaken to see the relationship between silage quality and the pattern of nitrate reduction during ensilage.

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Examining The Relationship Between Civic Agriculture Participation And Civic Engagement In South Texas, Allison Kaika, Dongkyu Kim, William Donner, Alexis Racelis, Owen Temby Jun 2026

Examining The Relationship Between Civic Agriculture Participation And Civic Engagement In South Texas, Allison Kaika, Dongkyu Kim, William Donner, Alexis Racelis, Owen Temby

School of Earth, Environmental, & Marine Sciences Faculty Publications

Civic agriculture is often credited with strengthening democratic life by encouraging civic and political engagement, yet this claim has scarcely been tested in socioeconomically marginalized regions. Using original survey data collected through a combination of random and purposive sampling, this study assesses that relationship in the Lower Rio Grande Valley of Texas, a majority-Hispanic agricultural region marked by high poverty and low civic participation. Phone and online surveys were administered in English and Spanish to reach both the general population and individuals involved in civic agriculture initiatives, yielding over 400 responses. We examine whether civic agriculture participation predicts greater community …

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Agrivoltaic Shading Reduces Soil Greenhouse Gas Fluxes In A Semi-Arid Vineyard, Marcelo Gomes Da Silva, Rafael M. Almeida, Carine Cocco, Engil Pereira Jun 2026

Agrivoltaic Shading Reduces Soil Greenhouse Gas Fluxes In A Semi-Arid Vineyard, Marcelo Gomes Da Silva, Rafael M. Almeida, Carine Cocco, Engil Pereira

School of Earth, Environmental, & Marine Sciences Faculty Publications

Agrivoltaic systems are expanding in semi-arid regions, raising questions about how panel driven shading alters soil greenhouse gas exchange. We used automated chambers to measure high frequency soil CO2, N2O, and CH4 fluxes in a newly established vineyard agrivoltaic system in Texas across three shading intensities (0%, 35%, 88%) that represent the light environment beneath panels as shaped by panel tilt and solar trajectory. Shading primarily cooled the soil, reducing mean soil temperature from 35.9 °C (0%) to 32.5 °C (35%) and 30.5 °C (88%), while mean soil water content shifted modestly (0.125, 0.106, and 0.130 m3 m−3, respectively). Over …

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Comparison Of Fish Biomass And Fish Carbon Content Associated With Reef Sites At The Rio Grande Valley Artificial Reef In The Gulf Of Mexico, Allison K. White, Md Saydur Rahman, Richard J. Kline Jun 2026

Comparison Of Fish Biomass And Fish Carbon Content Associated With Reef Sites At The Rio Grande Valley Artificial Reef In The Gulf Of Mexico, Allison K. White, Md Saydur Rahman, Richard J. Kline

School of Earth, Environmental, & Marine Sciences Faculty Publications

As global fisheries stocks have decreased due to overfishing and climate change, artificial reefs have gained significant attention. In addition to providing or restoring habitat, artificial reefs may serve as carbon capture sinks and potential climate mitigation strategies. The Rio Grande Valley (RGV) Reef is an artificial reef located in the northwestern Gulf of Mexico off the coast of Texas. The RGV Reef area spans 1,650 acres and is comprised of hundreds of groupings of recycled and pre-formed materials ranging from low relief (1–2 ft) to high relief (8–30 ft) reef structures. This reef provides a variety of novel habitat …

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Updates To The Caniform Fauna (Carnivora, Caniformia) Of The John Day Formation, Oregon, Usa, John D. Orcutt, Kevin C. Talbott, Michael J. Monroe, Nicholas A. Famoso Jun 2026

Updates To The Caniform Fauna (Carnivora, Caniformia) Of The John Day Formation, Oregon, Usa, John D. Orcutt, Kevin C. Talbott, Michael J. Monroe, Nicholas A. Famoso

Biology Faculty Scholarship

The John Day Formation of central Oregon preserves a diversity of Oligo-Miocene caniform carnivorans, many of which were first described from the formation. However, many historically important specimens lack detailed locality or stratigraphic information, complicating any analysis of faunal change through time. Here, we describe 16 new specimens of caniforms from the John Day Formation, most with precise stratigraphic information. We report multiple specimens of the amphicyonids Daphoenus Leidy, 1853, Paradaphoenus cuspigerus (Cope, 1878), and Temnocyon altigenis (Cope, 1878), all previously known from the formation. We also report the first definitive occurrence of the hesperocyonine canid Osbornodon Wang, 1994 from …

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Shallow-Marine Crinoid Genera May Have Been More Resilient Across Permian Extinction Events In Terms Of Richness Than Deep-Marine Crinoid Genera, Amelia C. Kolstad Jun 2026

Shallow-Marine Crinoid Genera May Have Been More Resilient Across Permian Extinction Events In Terms Of Richness Than Deep-Marine Crinoid Genera, Amelia C. Kolstad

University Honors Theses

Throughout the Phanerozoic, one of the most successful phyla of marine invertebrates has been Echinodermata. Echinodermata was particularly successful throughout the Paleozoic, with class Crinoidea making up a majority of occurrences. The proportion of echinoderm occurrences that are crinoids declined massively at the end of the Permian and continued to decrease into modern day, never fully recovering. One of the factors thought to have been so important for crinoid success in the Paleozoic and their decreasing success throughout geologic time has been their propensity for success in shallow-marine environments, though crinoids also exist within deep-marine environments. This study seeks to …

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Fate Of Nitrogen Applied To Grassland In Animal Wastes, M Sherwood May 2026

Fate Of Nitrogen Applied To Grassland In Animal Wastes, M Sherwood

IGC Proceedings (1977-2023)

The experiment was designed to determine the effects of land spreading of animal manures on the nutrient content of surface runoff water and infiltrating soil water. This report deals only with nitrogen (N) and attempts to quantify the losses through runoff, leaching, and volatilization of ammonia (NH3) as well as N uptake in the grass over a 3-year period. Experimental plots sited on grassland, on two soil types (a moderately drained loam and an impermeable gley), were equipped to collect surface runoff water. Ceramic probes were installed in each plot at 15-, 30-, 60-, and 100-cm depths to extract in­filtrating …

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Annual Losses Of Ammonia From A Grazed Pasture Fertilized With Urea, V R. Catchpoole, L A. Harper, R J.K Keyers May 2026

Annual Losses Of Ammonia From A Grazed Pasture Fertilized With Urea, V R. Catchpoole, L A. Harper, R J.K Keyers

IGC Proceedings (1977-2023)

Nitrogen-balance studies have shown losses of applied nitrogen (N) from grazed pastures in southeastern Queensland. Losses as high as 80% have been observed from urea N broadcast at 376 kg N/ha/yr over 8 years on a Setaria sp1uu:elata cv. Nandi pasture. Management techniques aimed at reducing this loss and thereby increasing the efficiency of use of N by pastures cannot be devised until the pathways of loss are known. The objective of this research was to estimate the annual ammonia (NH3) loss by convective transport from a urea-fertilized pasture at Samford Pasture Research Station in southeastern Queensland. Urea was broadcast …

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Nitrogen Losses From Urine-Affected Areas Of A New Zealand Pasture, Under Contrasting Seasonal Conditions, P R. Ball, D R. Keeney May 2026

Nitrogen Losses From Urine-Affected Areas Of A New Zealand Pasture, Under Contrasting Seasonal Conditions, P R. Ball, D R. Keeney

IGC Proceedings (1977-2023)

Grazing ruminants aggregate large quantities of forage nitrogen (N) into urine patches. Pasture plots treated with urine N were studied to assess its fate under contrasting seasonal conditions: cool-moist (representing winter-spring); warm-moist (late spring-early summer), and warm-dry (late summer-autumn). A permanent ryegrass (Lolium perenne L.)-white clover (Trifolium repens L.) sward on free-draining alluvial soil was studied. 'freatments were replicated in randomized blocks. Urine N was applied at 30 or 60 g N/m2• Relevant measurements were then continued until treatment differences disappeared. Apparent N balances for urine treatments were compiled. Fixation by white clover was always greatly reduced in …

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