Grain sorghum provides energy-rich seeds for waterfowl. I conducted experiments in 22 sorghum fields in Arkansas, Mississippi, and Louisiana during falls 2006 – 2007 to evaluate abundance of ratoon grain (i.e., second crop after harvest), waste grain, and natural seeds. I also conducted surveys of wintering waterfowl in flooded croplands and moist-soil wetlands to evaluate if ducks and geese differentially used habitats. Fertilized plots in 2007 produced >4 times more ratoon grain (x = 219.57 ± 39.65 [SE] kg/ha) than other treatments. Fertilized plots in southern regions of my study area produced ~5 times more ratoon grain (x = 262.93 ± 50.28 kg/ha) than others. Mallards and other ducks used moist-soil wetlands (x >65 ducks/ha) more than other habitats. I did not observe geese using flooded sorghum. I recommend not manipulating sorghum stubble after harvest, fertilizing, and flooding it after ratoon grain has matured, and integrating moist-soil wetlands into agricultural lands.

No description available.

No description available.

Dramatic alterations have occurred on agricultural landscapes throughout North America, reducing the quantities of herbaceous habitat that once dominated field margins. A concomitant decrease of grassland bird populations paralleled these modifications. Conservation buffers, in the form of field borders, are a method of habitat establishment that effectively balances wildlife and landowner needs. Recent popularity of field borders led to their establishment throughout the southeastern US despite a paucity of knowledge regarding avian response to management regimes. This research evaluated wintering and breeding avian communities, as well as nesting ecology in response to field border establishment. Results indicated that birds utilize field borders for various life history requirements. Field borders provided enhanced avian benefits over traditional farm practices; and borders of widths >10 m were superior nesting habitat than more narrow borders. Based on these results, we strongly recommend field border establishment to enhance ecosystem integrity on farm landscapes.

[EN] The understanding of the mechanical behaviour of natural intact soils is central to engineers when designing new structures. The research carried in this thesis focused on investigating the effects of the naturally occurring in-situ structure on the mechanical behaviour of two shallow recently deposited Holocene alluvial materials, the Bormida River silts (BRS) from Italy and the Valencia silty soils (VSS) from the alluvial plains of the Turia River, Spain. These types of deposits are frequently characterised by highly heterogeneous in-situ structures. A large range of soils with different size distributions from sands to silty clays were investigated. Oedometer and triaxial tests were carried out on intact, slurry and compacted samples. The first step was to characterise the behaviour of the materials at their reconstituted state to define the reference framework for investigating the effect of the in-situ structure of the intact specimens. The effects of the sample preparation technique on the mechanical behaviour were examined, in particular its influence on the uniqueness of the normal compression line and critical state line. The initial structure created during the preparation of the specimens was totally removed after compression and shearing regardless of the sample preparation method. Only one soil displayed a clear effect of the sample preparation technique, the oedometer compression lines of which remained parallel to each other even at a very high stress levels for the case of the slurry samples. This result showed that contrary to what is stated in the literature the sample preparation technique can created very robust initial structures resulting in a transitional behaviour. Clears effects of the in-situ structure of the intact samples of the BRS and VSS were observed on the oedometer compression behaviour even at very high stress levels with stress sensitivity values still larger than unity at the end of the tests. It appeared that the effects were more noticeable as the degree of heterogeneity inside the specimens increased at a meso-structure level as it was the case of some samples of the VSS materials which exhibited a certain layering. Small effects of the in-situ structure were seen at large shearing strains and only on the wet side of the critical state. / [ES] El conocimiento del comportamiento mecánico de los suelos en su estado natural es de importancia capital para los ingenieros a la hora de diseñar nuevas obras. La investigación desarrollada en esta Tesis se centra en descubrir los efectos que tiene la estructura del suelo en su estado natural en la respuesta mecánica de dos suelos aluviales holocenos, depositados superficialmente: los limos del río Bormida (BRS) en Italia y los suelos limosos provenientes de la llanura aluvial del río Turia (VSS) en España. Este tipo de suelos se caracterizan frecuentemente por una estructura inicial altamente heterogénea. Se ha ensayado una gran variedad de muestras con diferentes granulometrías, desde arenas a arcillas limosas en las que se han realizado ensayos edométricos y triaxiales en muestras intactas, compactadas y en muestras reconstituidas (slurry). En una primera etapa de la investigación se caracterizó la respuesta del material en su estado reconstituido para definir un marco de referencia con el que poder comparar la respuesta de las muestras intactas tomadas in situ y que preservan su estructura natural (inalteradas). Se ha analizado la influencia del modo de preparación de las muestras en su comportamiento mecánico, y, en particular, en la unicidad de las curvas de compresión noval y de estado critico. Se ha comprobado que la estructura inicial inducida durante el proceso de preparación desaparece completamente tras someter la muestra a compresión y corte, independientemente del método de preparación utilizado. Únicamente un suelo mostró, de un modo nítido, el efecto de la técnica de preparación, de modo que las líneas de compresión edométrica se mantuvieron paralelas incluso a niveles de tensión elevados en el caso de muestras reconstituidas (slurry). Este resultado demostró, contrariamente a la opinión aceptada en la bibliografía, que el sistema de preparación de la muestra puede crear una potente estructura inicial dando lugar a un comportamiento de tipo transicional. En los ensayos de compresión edométrica se ha podido comprobar un claro efecto positivo de la estructura inicial de las muestras intactas, incluso a niveles altos de tensión, observándose índices de sensitividad tensional superiores a uno al final de los ensayos, de modo que para igualdad de índice de huecos, la tensión efectiva vertical de la muestra intacta es superior a la correspondiente en la muestra reconstituida. Aparentemente, este efecto es tanto más significativo cuanto mayor es el grado de heterogeneidad interno de la muestra a nivel de meso-estructura, como se pudo observar en algunas muestras de los suelos (VSS) que presentaban niveles de laminación horizontal. En los ensayos de corte la influencia de la estructura intacta fue relativamente pequeña y únicamente en el lado húmedo del estado critico. / [CA] Conèixer el comportament mecànic dels sòls en el seu estat natural és d'importància capital per als enginyers a l'hora de dissenyar noves obres. La investigació desenvolupada en aquesta Tesi se centra a descobrir els efectes de l'estructura del sòl en el seu estat natural en la resposta mecànica de dos sòls al¿luvials holocens, dipositats superficialment: els llims del riu Bormida (BRS) a Itàlia i els sòls llimosos provinents de la plana al¿luvial del riu Túria (VSS) a Espanya. Aquests tipus de sòls es caracteritzen sovint per una estructura inicial altament heterogènia. S'ha assajat una gran varietat de mostres amb diferents granulometries, des d'arenes fins a argiles llimoses amb les quals s'han realitzat assajos edomètrics i triaxials en mostres intactes, compactades i en mostres reconstituïdes (slurry). En una primera etapa de la investigació es va caracteritzar la resposta del material en el seu estat reconstituït per a definir un marc de referència amb el qual poder comparar la resposta de les mostres intactes preses in situ i que preserven la seua estructura natural (inalterades). S'ha analitzat la influència del mètode de preparació de les mostres en el seu comportament mecànic i en particular, en la unicitat de les corbes de compressió noval i d'estat crític. S'ha comprovat que l'estructura inicial induïda al llarg del procés de preparació desapareix completament després de sotmetre la mostra a compressió i tall, independentment del mètode de preparació utilitzat. Únicament un sòl va mostrar clarament l'efecte de la tècnica de preparació, de manera que les línies de compressió edomètrica es van mantenir paral¿leles fins i tot a nivells de tensió elevats en el cas de mostres reconstituïdes (slurry). Aquest resultat va demostrar, contràriament a l'opinió acceptada en la bibliografia, que el sistema de preparació de la mostra pot crear una potent estructura inicial donant lloc a un comportament de tipus transicional. Als assajos de compressió edomètrica s'ha pogut comprovar un clar efecte positiu de l'estructura inicial de les mostres intactes, inclús a nivells alts de tensió, observant-se índexs de sensitivitat tensional superiors a la unitat al final dels assajos, de manera que per a igualtat d'índex de buits, la tensió efectiva vertical de la mostra intacta és superior a la corresponent en la mostra reconstituïda. Aparentment, aquest efecte és més significatiu quant major és el grau d'heterogeneïtat intern de la mostra a nivell de meso-estructura, com es va poder observar en algunes mostres dels sòls (VSS) que presentaven nivells de laminació horitzontal. Als assajos de tall la influència de l'estructura intacta va ser relativament petita i únicament en el costat humit de l'estat crític." / Carrión Carmona, MÁ. (2016). The effects of the structure on the mechanical behaviour of young Holocene alluvial materials from the Bormida River (Italy) and Turia River (Spain) [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63470

The expanding irrigated acreage in the Mississippi Delta has resulted in increased withdrawals that exceed the recharge rate of the Mississippi River Valley Alluvial Aquifer (MRVAA), leading to a decline in water levels. This trend poses a threat of rapid depletion, potentially resulting in deteriorating water quality and increased pumping costs in the region. Water-conserving irrigation practices are a key component to any potential solution, promising enhanced water use efficiency and sustainable agricultural practices. Nonetheless, farmers adopt these practices at different times. This study used a duration model to identify the factors that influence the timing of adoption of computerized hole selection (CHS) and center pivot (CP) practices. We found that farmers who attended extension meetings and held the belief that CHS would lower their input costs adopted it more promptly. Also, participation in conservation programs facilitated the quicker adoption of CP. Conversely, greater farming experience and a higher cumulative number of adopters were associated with slower adoption times for both CHS and CP.

A combination of geological and hydraulic techniques represents the most sensible approach to flood hazard analysis on alluvial fans. Hydraulic models efficiently yield predictions of flood depths and velocities, but the assumptions on which the models are based do not lead to accurate portrayals of natural fan processes. Geomorphological mapping, facies, mapping, and hydraulic reconstructions of past floods provide data on the location, types, and magnitude of flood hazards, respectively. Geological reconstructions of past floods should be compared with the results of hydraulic modeling before, potentially unsound, floodplain management decisions are implemented. The controversial Federal Emergency Management Agency procedure for delineating flood-hazard zones underestimated the extent, velocity, and depth of flow during recent floods on two alluvial fans by over 100, 25, and 70 percent, respectively. Flow on the alluvial fans occurs in one or more discontinuous ephemeral stream systems characterized by alternating sheetflood zones and channelized reaches. The importance of sheetflooding is greater on fans closer to the mountain front and with unstable channel banks. Channel diversions on five alluvial fans repeatedly occurred along low channel banks and bends where the greatest amount of overland flow is generated. Channel migration occurs through stream capture whereby overland flow from the main channel accelerates and directs erosion of adjacent secondary channels. The recurrence interval of major channel shifts is greater than 100 years, but minor changes occurred on all five fans during this century. Small aggrading flows are important, because they decrease bank heights and alter the location of greatest overland flow during subsequent floods. The results of this study demonstrate that (1) geological reconstructions of past floods can check the results of hydraulic models, (2) the character of flooding on alluvial fans can vary significantly in the same tectonic and climatic setting due to differences in drainage-basin characteristics, and (3) flood-hazard assessments on alluvial fans must be updated after each flood, because the location and timing of channel diversions can be affected by small floods.

In South Central Cut Bank Sand Unit (SCCBSU) of Cut Bank field, primary production and waterflood projects have resulted in recovery of only 29 % of the original oil in place from heterogeneous, fluvial sandstone deposits. Using highresolution sequence stratigraphy and geostatistical analysis, I developed a geologic model that may improve the ultimate recovery of oil from this field. In this study, I assessed sequence stratigraphic concepts for continental settings and extended the techniques to analyze low-accommodation alluvial systems of the Cut Bank and Sunburst members of the lower Kootenai formation (Cretaceous) in Cut Bank field. Identification and delineation of five sequences and their bounding surfaces led to a better understanding of the reservoir distribution and variability. Recognition of stacking patterns allowed for the prediction of reservoir rock quality. Within each systems tract, the best quality reservoir rocks are strongly concentrated in the lowstand systems tract. Erosional events associated with falling baselevel resulted in stacked, communicated (multistory) reservoirs. The lowermost Cut Bank sandstone has the highest reservoir quality and is a braided stream parasequence. Average net-to-gross ratio value (0.6) is greater than in other reservoir intervals. Little additional stratigraphically untapped oil is expected in the lowermost Cut Bank sandstone. Over most of the SCCBSU, the Sunburst and the upper Cut Bank strata are valley-fill complexes with interfluves that may laterally compartmentalize reservoir sands. Basal Sunburst sand (Sunburst 1, average net-to-gross ratio ~0.3) has better reservoir quality than other Sunburst or upper Cut Bank sands, but its reservoir quality is significantly less than that of lower Cut Bank sand. Geostatistical analysis provided equiprobable representations of the heterogeneity of reservoirs. Simulated reservoir geometries resulted in an improved description of reservoir distribution and connectivity, as well as occurrences of flow barriers. The models resulting from this study can be used to improve reservoir management and well placement and to predict reservoir performance in Cut Bank field. The technical approaches and tools from this study can be used to improve descriptions of other oil and gas reservoirs in similar depositional systems.

Three seasons of initial succession were followed in the frame of this thesis after a restoration project in a section of the Stropnice River and its floodplain. The succession tends towards formation of community of alluvial meadows, which is prevailing biotope in the neighborhood of the restored part. Strong factor influencing the course of succession is wetness of the substrate, which is partially given by distance of a site from the water-course and by the difference in the altitude of a site and of the river water table. Synantrophic species were most abundant in the first year (2014), followed by meadow and wetland species (2015, 2016).

Le développement industriel et urbain accroit la pollution des eaux au Cameroun. Il faut donc rechercher des méthodes de dépollution peu onéreuses et de mise en oeuvre facile. L'objectif de ce travail était d'éliminer les métaux lourds (Cu2+, Pb2+, Hg2+, Cr3+) des eaux usées, par adsorption sur de l'argile brute ou traité thermiquement. L'argile alluviale prélevée dans la région de l'Extrême Nord du Cameroun est essentiellement composée de smectite (46%), kaolinite (38%), interstratifiés (10%) et quartz (5%). Les formules structurales sont (Si3,42Al0,58)(Al0,87Fe0,96Mg0,17)O10(OH)2(C+)0,75 , pour la smectite et Si2Al1,95Fe0,05O5(OH)4. pour la kaolinite. Les cations de métaux lourds s'adsorbent très rapidement sur l'argile brute ; la température et le pH de la solution influencent peu leur adsorption. L'affinité de l'argile pour Cu2+, et Pb2+ est très forte mais faible pour Hg2+ et Cr3+. Le mécanisme proposé est l'échange cationique et la complexation de surface pour l'adsorption de Cu2+, Pb2+ et Cr3+ et un mécanisme de spéciation pour l'adsorption de Hg2+. Les boulettes obtenues par traitement thermique de l'argile au dessus de 500°C sont stables en solution et montrent une bonne capacité d'adsorption des métaux lourds. Les boulettes sont moins efficaces que l'argile brute, mais leur utilisation, évitant la séparation solide-liquide, après adsorption est plus facile / The industrial and urban development increases the water pollution in Cameroon. It becomes imperative to develop inexpensive and easy to manage remediation methods. This work aimed at eliminating heavy metals (Cu2+, Pb2+, Hg2+, Cr3+) from water by adsorption on raw or heat treated clay. The alluvial clay sampled in the far North of Cameroon mainly contains smectite (46%), kaolinite (38%), interlayers (10%) and quartz (5%). The structural formulas are : (Si3,42Al0,58)(Al0,87Fe0,96Mg0,17)O10(OH)2(C+)0,75 for the smectite and Si2Al1,95Fe0,05O5(OH)4 for the kaolinite. The heavy metals cations fastly adsorb on raw clay, the temperature and the pH have not much influence on their adsorption. The clay affinity in relation to Cu2+, and Pb2+ is very strong whereas it is low for Hg2+, Cr3+. For the adsorption of Cu2+, Pb2+ and Cr3+ the proposed mechanisms are the cation exchange and the complexation while for the Hg2+, a mechanism of speciation is involved. The pellets obtained by thremic treatment of the clay above 500°C are stable in solution and they have a good capacity for heavy metals adsorption. Performances of the pellets are lower than those of raw clay, however, their use is easier since they do not need solid-liquid separation after adsorption