Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

56,647 Full-Text Articles 66,532 Authors 9,109,310 Downloads 260 Institutions

All Articles in Earth Sciences

Faceted Search

56,647 full-text articles. Page 6 of 2087.

Uranium And Thorium Enrichment Characteristics Of Bauxite In Coal Measure Strata And Their Natural Gamma-Ray Responses, ZHANG Xiaohui, ZHANG Shangqing, LIU Dongna, ZHAO Fenghua, ZHAO Jun, ZHONG Zhuanghua, HOU Xuqin 2024 College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, China

Uranium And Thorium Enrichment Characteristics Of Bauxite In Coal Measure Strata And Their Natural Gamma-Ray Responses, Zhang Xiaohui, Zhang Shangqing, Liu Dongna, Zhao Fenghua, Zhao Jun, Zhong Zhuanghua, Hou Xuqin

Coal Geology & Exploration

Shanxi Province boasts abundant bauxite resources occurring in coal measure strata, with the deep bauxite resources in this province subjected to progressive assessment. This study aims to further determine the endowment of aluminum resources within coals in the province and explore efficient exploration methods. To this end, this study investigated the bauxite layers in Upper Carboniferous coal measure strata in the Xiaoyi area, Shanxi Province. It examined 37 samples from three boreholes using methods such as optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), and inductively coupled plasma mass spectrometry (ICP-MS). Based on the analysis …


Numerical Simulation On Influence Of Skin Effect On Groundwater Flow Velocity In Wellbore, WANG Qihang, LI Xu, GUO Qiang, KUAI Dawei 2024 State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, Beijing 100011, China; School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China

Numerical Simulation On Influence Of Skin Effect On Groundwater Flow Velocity In Wellbore, Wang Qihang, Li Xu, Guo Qiang, Kuai Dawei

Coal Geology & Exploration

Groundwater flow velocity in wellbore is usually measured by single-well tracking tests or Aqua Vision flow velocity and direction meters to calculate the groundwater flow velocity in the aquifer. Due to the impact of the skin structure, the groundwater flow field near the wellbore changes, causing a difference between the flow velocity in the wellbore and that in the aquifer. In order to investigate the influence of the skin effect on the groundwater flow velocity in the wellbore, a numerical model of groundwater flow that considers the skin effect was established using the COMSOL Multiphysics software. On this basis, the …


Law Governing Variations In Water-Pressure Transmission Rate In Confined Aquifers, WANG Wenxue, WANG Bosen, GAO Yanwei, WU Bing, NIE Tianyu 2024 Henan Province Key Laboratory of Rock and Soil Mechanics and Structural Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, China; Key Laboratory of Xinjiang Coal Bearing Resources Exploration and Exploitation, Urumqi 830023, China; Henan Provincial International Joint Laboratory for Landslide Flow Monitoring and Early Warning, North China University of Water Resources and Electric Power, Zhengzhou 450045, China

Law Governing Variations In Water-Pressure Transmission Rate In Confined Aquifers, Wang Wenxue, Wang Bosen, Gao Yanwei, Wu Bing, Nie Tianyu

Coal Geology & Exploration

The water pressure in aquifers is transmitted as energy, with a transmission rate much higher than the migration rate of water particles. The water-pressure transmission rate holds great significance for the safe construction and disaster forecast and prediction of underground engineering under high-pressure water aquifers and bodies. Focusing on the confined aquifers bearing no cohesive soil, this study explored the law governing the changes in the water-pressure transmission rate through theoretical analysis, numerical simulations, field experiments, and laboratory physical model tests. Key findings are as follows: (1) The transmission of water-pressure changes in the aquifers exhibited noticeable hysteresis. The transmission …


Experimental Study On Acoustic Emission Evolution Characteristics And Response Mechanism Of Damaged Rocks, ZHANG Kai, ZHANG Dongxiao, ZHAO Yongqiang, YANG Yingming, GUO Weiyao, SUN Peng, XU Linpeng, FU Guangsheng 2024 State Key Laboratory of Water Resources Protection and Utilization in Coal Mining, National Institute of Clean-and-Low-Carbon Energy, Beijing 102211, China; China Energy Investment Group Co., Beijing 100011, China

Experimental Study On Acoustic Emission Evolution Characteristics And Response Mechanism Of Damaged Rocks, Zhang Kai, Zhang Dongxiao, Zhao Yongqiang, Yang Yingming, Guo Weiyao, Sun Peng, Xu Linpeng, Fu Guangsheng

Coal Geology & Exploration

The evolution of rock internal damage is one of the causes of geotechnical engineering disasters, and revealing the response characteristics of key parameters during the rock failure could provide a basis for the identification instability state after rock failure, which is of great importance for the early warning and prevention of rock engineering disasters. Herein, the siltstone specimens with different damage degrees were prepared by cyclic loading-unloading tests, and uniaxial loading tests were carried out with the damaged specimens. On this basis, the relationship between the damage degree of specimen and the wave velocity, as well as the acoustic emission …


Silvopastoral Agroforestry In Upland And Lowland Uk Grassland: Tree Growth And Animal Performance, W R. Eason, R Lavender, R O. Clements, C Duller, E Gill, M Hislop 2024 Institute of Grassland and Environmental Research, UK

Silvopastoral Agroforestry In Upland And Lowland Uk Grassland: Tree Growth And Animal Performance, W R. Eason, R Lavender, R O. Clements, C Duller, E Gill, M Hislop

IGC Proceedings (1997-2023)

Trees, individually protected from herbivore damage using plastic shelters, were planted at two densities (100 and 400 stems/ha) into sheepgrazed pasture in upland and lowland UK grassland sites in 1988. Tree and animal performance were compared with conventional forestry (no sheep) and pasture (no tree) systems. Effects on tree growth and survival are highly species and site dependent although some treatment effects did emerge. Tree shelters encouraged rapid early height growth compared to forestry controls although in some cases tree form was also adversely affected. Generally tree performance within agroforestry treatments was better at the higher planting density. Eight years …


Use Of Annual Self-Reseeding Legumes In An Oak Forest In Central Italy, P Talamucci, G Argenti, A Pardini, S Piemontese, N Stagliano 2024 Universita di Firenze, Italy

Use Of Annual Self-Reseeding Legumes In An Oak Forest In Central Italy, P Talamucci, G Argenti, A Pardini, S Piemontese, N Stagliano

IGC Proceedings (1997-2023)

A trial has been carried out for three years in an oak coppice geometrically thinned out of Mediterranean Central Italy, about the functioning of a pastoral system made by four different resources: native pasture, subterranean clover (Trifolium brachycalycinum Katzn. et Morley) in pure stand, strips thinned out and firebreaks improved with oversown subclover, all grazed by sheep. Subclover increased the forage yield and improved the palatabilty of the pasture and the regularity of grazing; the higher biomass intake by animals reduced the quantity of dried biomass in summer and contributed to keep low either fire hazards or flame diffusion …


The Effects Of Shelterbelts On Adjacent Pastures And Soils In A Temperate Climate, A G. Gillingham, M F. Hawke 2024 AgResearch, Palmerston North

The Effects Of Shelterbelts On Adjacent Pastures And Soils In A Temperate Climate, A G. Gillingham, M F. Hawke

IGC Proceedings (1997-2023)

Two trials were conducted to differentiate the direct (exposure) from the indirect (modified soil fertility due to nutrient transfer by grazing animals) effects of farm shelterbelts on associated pasture growth.Soil from close to “unmanaged”shelterbelts with dense shelter to ground level had relatively high potassium (K) levels and, in a glasshouse situation, provided more pasture growth than soil from further distances, or from adjacent to “managed” shelterbelts. Pasture grown in boxes of a common soil implanted at increasing distances from a shelterbelt also produced highest growth rates close to shelter. These results generally explain the pattern of resident pasture growth, except …


Temperate Pasture And Sheep Performance Under Radiata Pine And In Open Pasture, K M. Pollock, R J. Lucas, D B. Pownall, S E. Thomson 2024 Lincoln University, NZ

Temperate Pasture And Sheep Performance Under Radiata Pine And In Open Pasture, K M. Pollock, R J. Lucas, D B. Pownall, S E. Thomson

IGC Proceedings (1997-2023)

Forage production from years 4 to 6 of an agroforestry system at 400-600 trees per ha and pasture alone were compared for a temperate sub-humid environment. Forage production was best for lucerne pasture followed by phalaris/clover and cocksfoot/clover, and least for ryegrass/clover and the ryegrass only pastures. Total pasture production in the agroforest relative to the open pasture was from 10% more for phalaris to 20% less for lucerne. Sheep carrying capacity over all pastures was 14.6 sheep/ha in the open and 11.8 sheep/ha in the agroforest and varied by ±15% according to the pasture types.


Grazing Management Of Tagasaste (Chamaecytisus Proliferus) For Sheep And Cattle Production In Southern Australia, N J. Edwards, G M. Allen, D M. McNeill, C M. Oldham 2024 The University of Western Australia

Grazing Management Of Tagasaste (Chamaecytisus Proliferus) For Sheep And Cattle Production In Southern Australia, N J. Edwards, G M. Allen, D M. Mcneill, C M. Oldham

IGC Proceedings (1997-2023)

Direct grazing of hedgerows of tagasaste (Chamaecytisus proliferus) by sheep or cattle appear to be very robust systems. Tagasaste persists under a continuous grazing regime with cattle such that plant regrowth maintained between 5 and 10 cm in length produces in excess of 215 kg of animal liveweight/ha/year. This level of production is also sustained within a rotational grazing regime. Under both grazing systems cattle production within a year is highly seasonal, with liveweight gains from young cattle peaking at 1.0-1.5 kg/head/day in winter and spring, but dropping to maintenance only by late summer-autumn. Sheep, like cattle, can …


Shrub Palatability To Rusa Deer (Cervus Timorensis Russa) In New Caledonia, C Corniaux, S Le Bel, J M. Sarrailh 2024 Centre de CoopÈration Internationale en Recherche Agronomique pour le DÈveloppement

Shrub Palatability To Rusa Deer (Cervus Timorensis Russa) In New Caledonia, C Corniaux, S Le Bel, J M. Sarrailh

IGC Proceedings (1997-2023)

The objective of this study was to determine a palatability scale of five shrub legumes to rusa deer during the dry season in New Caledonia. Acacia ampliceps and Samanea saman remain low in acceptability. Gliricidia sepium is more palatable but quite less than Leucaena leucocephala (native cultivar) and Calliandra calothyrsus (San Ramon). Therefore, since the regression of Leucaena leucocephala population, Calliandra calothyrsus could be very promising to replace it in the deer diet. On the other hand, Acacia ampliceps seems to be the most interesting shrub legume to plant in the west coast, where soil erosion, due to successive droughts …


Soil Nutrient Redistribution Pattern About The Tree In A Silvopastoral System, L C. Nwaigbo, H G. Miller, A R. Sibbald, G Hudson 2024 University of Aberdeen

Soil Nutrient Redistribution Pattern About The Tree In A Silvopastoral System, L C. Nwaigbo, H G. Miller, A R. Sibbald, G Hudson

IGC Proceedings (1997-2023)

The objective of this paper is to report the effect of animal-tree interactions on soil nutrient redistribution pattern in a grazed silvopastoral experiment site at Glensaugh, in NE Scotland. Scots pine (Pinus sylvestris L) tree species were planted in square lattice arrangements at 5 m x 5 m, spacing (400 stems/ha) on plots replicated over three blocks in Randomized Complete Block design on a predominantly rye grass (Lolium perenne L) pasture which was grazed by sheep yearly from April to October. Included in the design were grazed pasture plots without trees (Control). Soil samples were collected from around …


Trees For Shelter: The Implications In Agroforestry System, L C. Nwaigbo, A R. Sibbald, G Hudson 2024 University of Aberdeen

Trees For Shelter: The Implications In Agroforestry System, L C. Nwaigbo, A R. Sibbald, G Hudson

IGC Proceedings (1997-2023)

The objective of this study was to determine the horizontal and vertical variations in soil penetration resistance (PR) observed at tree-scale in silvopastoral plots that were grazed by sheep with and without trees. Sycamore trees (Acer pseudoplatanus L) were planted in the spring of 1988 at 10 m x 10 m spacing (100 stems/ha) at Glensaugh NE of Scotland on plots replicated over three blocks in Randomized Complete Block design on a predominantly rye grass (Lolium perenne L) pasture. Included in the design were pasture plots without trees (Control). The experiment is grazed by sheep yearly from April to …


A Silvopastoral System In The North Atlantic Zone Of Costa Rica: Combining Indigenous Timber Species With Dairy Pasture Swards, A Moulaert- Quiros, J P. Mueller, M Villarreal, R Piedra, L Villalobos 2024 North Carolina State University

A Silvopastoral System In The North Atlantic Zone Of Costa Rica: Combining Indigenous Timber Species With Dairy Pasture Swards, A Moulaert- Quiros, J P. Mueller, M Villarreal, R Piedra, L Villalobos

IGC Proceedings (1997-2023)

The objective of this study was to design, establish and monitor a silvo pastoral experiment on a dairy farm in the northern Atlantic region of Costa Rica. Indigenous timber species, Vochysia guatemalensis and Hyeronima alchorneoides were used together with or without the tropical pasture legume, Arachis pintoi in a split plot design with a 4 x 2 x 2 factorial arrangement. First year establishment was good for the tree component (2.3 to 10 % mortality) but poor for A. pintoi (4 to 5 % of sward). Poor legume establishment was attributed to lax grazing management and excess competition from existing …


Productivity Of Three Tree Legumes Grazed By Cattle, R C. Gutterridge 2024 The University of Queensland, Australia

Productivity Of Three Tree Legumes Grazed By Cattle, R C. Gutterridge

IGC Proceedings (1997-2023)

Three tree legumes Albizia chinensis, Leucaena leucocephala K 636 and Tipuana tipu were grown in conjunction with the grass Brachiaria decumbens and grazed by weaner cattle at a stocking rate of 2.5 animals per hectare for a total of 447 days. Albizia was best adapted to this acidic, poorly drained site in south east Queensland giving the highest yields of edible dry matter, high survival rate and moderate liveweight gains of 0.45 kg/head/day. The productivity of L. leucocephala K 636 was always poor but it gave the highest liveweight gains of all treatments in the first 280 days of grazing, …


Morphological And Physiological Response Of Planeleaf Willow (Salix Planifolia Pursh.) To Simulated Browsing, L Xu, J L. Dodd, M A. Smith, Q D. Skinner, W A. Laycock 2024 North Dakota State University--Fargo

Morphological And Physiological Response Of Planeleaf Willow (Salix Planifolia Pursh.) To Simulated Browsing, L Xu, J L. Dodd, M A. Smith, Q D. Skinner, W A. Laycock

IGC Proceedings (1997-2023)

Morphological and physiological responses of planeleaf willow (Salix planefolia Pursh.) to simulated browsing were studied under controlled conditions. The treatments consisted of every combination of three clipping intensities (30%, 60% and 90% of current twigs length removal) and three clipping timings (late winter, early spring and mid-summer). Increased clipping intensity stimulated bud activation; increased total leaf area and leaf size and increased the length of current year’s twigs. Mid-summer browsing increased the total number of leaves, the number of current twigs and decreased the length of current twigs. Higher browsing intensity resulted in higher photosynthetic rate of recently matured …


Psyllid Resistance In The Leucaena Genus, B F. Mullen, H M. Shelton, F Gabunada, W W. Stur 2024 The University of Queensland, Australia

Psyllid Resistance In The Leucaena Genus, B F. Mullen, H M. Shelton, F Gabunada, W W. Stur

IGC Proceedings (1997-2023)

Leucaena species varied from highly susceptible to highly resistant in their response to the psyllid insect (Heteropsylla cubana) at 2 sites, a high psyllid environment at Brisbane, Australia and a moderate psyllid environment at Los Baños, Philippines. L. leucocephala was the most susceptible species. There was considerable intraspecific variation in psyllid resistance within L. collinsii, L. diversifolia and L. pallida. Plant reponse to psyllid challenge between environments was highly correlated but not linear. The higher psyllid challenge environment at Brisbane permitted greater discrimination between species and fewer Leucaena species were ranked as psyllid resistant.


Fodder Production Of Multipurpose Trees In A Maize Farming System Of Subhumid Southern Africa, B H. Dzowela, L Hove, P L. Mafongoya 2024 SADC-ICRAF, Zimbabwe

Fodder Production Of Multipurpose Trees In A Maize Farming System Of Subhumid Southern Africa, B H. Dzowela, L Hove, P L. Mafongoya

IGC Proceedings (1997-2023)

Ways to integrate fodder production into maize production systems under Southern Africa’s subhumid conditions have been studied. One way involves the planting of tree and grass fodder hedges along soil conservation contour-bunds in maize fields. Management factors that influence the productivity of maize and fodder components in the system are fodder spp., side-pruning and deferment of wet season cutting. The other option involves interplanting tree fodders with maize through the use of a coppicing tree such as Acacia angustissima. Practical applications of these methods in mixed crop-livestock production systems are discussed.


Differences In Chemical Composition Among Provenances Of Browse Species In A Subhumid Environment: Relation To Use As Supplements, B H. Dzowela, L Hove, P L. Mafongoya 2024 SADC-ICRAF

Differences In Chemical Composition Among Provenances Of Browse Species In A Subhumid Environment: Relation To Use As Supplements, B H. Dzowela, L Hove, P L. Mafongoya

IGC Proceedings (1997-2023)

Studies were initiated in a subhumid Southern African environment to assess the chemical composition and nutritive value of Acacia angustissima (Mill.) Kuntze, Calliandra calothyrsus Meiss. and Leucaena species. The objective was to determine variability in crude protein (CP) concentration, acid detergent fibre (ADF), neutral detergent fibre (NDF), and soluble and insoluble proanthocyanidins from fodder samples of species, subspecies and provenances. A wide range was found in these parameters. The implications of these chemical composition factors, especially proanthocyanidins, on the use of these browse fodders in livestock feeding systems are discussed.


Tree Forages As Nitrogen Source For Ruminants In Sahelian Agro-Silvipastoral Systems, S T. Fall, B M. Doreau 2024 ISRA LNERV

Tree Forages As Nitrogen Source For Ruminants In Sahelian Agro-Silvipastoral Systems, S T. Fall, B M. Doreau

IGC Proceedings (1997-2023)

Tree forages contribute up to 80% DM and 100% nitrogen content in the ruminants diet in the Sahel during the dry season. However, crude protein (CP) concentration in browse within a wide range and variation factors remain to be elucidated for better integration of browses in ruminants feeding systems. Variation factors of CP content and in vivo digestibility of four Sahelian browse species were investigated to appreciate the potential as nitrogen sources in Sahelian ruminant feeding systems. Seasonal variations in nitrogen content were evaluated in different plants part of A. raddiana, B. rufescens, B. aegyptiaca and G. senegalensis harvested in …


Introduction Of Multipurpose Tree Species For Improving The Productivity Of Grasslands In The Tropics, N G. Hegde, C Sall, T Nolan, J Connolly 2024 BAIF Development Research Foundation, India

Introduction Of Multipurpose Tree Species For Improving The Productivity Of Grasslands In The Tropics, N G. Hegde, C Sall, T Nolan, J Connolly

IGC Proceedings (1997-2023)

To improve the productivity of the Sahelian pastures, 10 different tree species were introduced and cattle, sheep and goats were allowed to graze. After a year of establishment, survival rate of different species ranged from 6% to 68%. Acacia senegal, Acacia seyal, Acacia nilotica, Combretum aculeata and Prosopis cineraria performed well and the impact of browsing by goats was severe.


Digital Commons powered by bepress