Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Annual medic pastures play an important role in conservation agriculture (CA) practices in the Western Cape, because of the beneficial role it plays in rotation systems and the fact that it can re-establish on its own. In the Overberg medic pastures are the main pasture short rotation crop, but farmers in recent years shifted away from including medics. This was due to unsuccessful re-establishment and a visible decrease in dry matter production. This trend started after CA practices were implemented for a few years. A field study conducted during 2013 investigated medic re-establishment and production following a wheat, barley, oat and medic pasture production year ( WM, BM, OM and MM) of which residues were left on the soil surface at different cover percentage levels (100%, 75%, 50%, 25% and 0%). The objective of this study was to determine what the effect of different amounts of residues was on annual medic re-establishment and production. Data from this study suggest that management of annual medic pastures should aim to re-sow the medic pasture if plant count drops below 78 pants per square meter. Weed management is of cardinal importance as it competes for resources, light and space and decrease medic pasture re-establishment and production. The data also indicates that the wheat/medic sequence is the best option when applying a short cash crop/annual pasture cropping system. Producers should manage their animals to ensure that a 50% to 75% cover is left on top of the soil following the grazing of residues during the summer months. The study in 2013 should have been replicated, but due to the low levels of re-establishment and production a decision was made to re-plant the trial sites. The field study conducted during 2014 investigated the medic/clover establishment and production following a re-plant. Medics were replanted following a W, B, O and M season, respectively. Residues again were manipulated to different cover percentages (100%, 75%, 50%, 25% and 0%). The objective was again to look at the amount and type of residues on medic/clover establishment and production following re-plant. Data from this study indicated that it might be advisable for annual medic/clovers to be re-sown after a cereal production year rather than a medic pasture year. With the production of medic/clover pastures not being affected by the residue cover percentage, a 100% residue cover following re-plant is best in rotations, if the optimal effect of CA wants to be observed. If animals are included in the production cycle, grazing of residues during summer months can occur until 50% cover is left. Soils will take longer to reach its potential, but by including animals the gross margin is more stable year on year. Two supplementary studies were conducted to investigate the germination of annual medics under controlled conditions. The objectives of the first supplementary study was to investigate the physical barrier effect of residues at different percentage cover (100%, 75%, 50%, 25% and 0%) and a possible allelopathic action from different types of residues (wheat, barley, oat and medic) on the annual medic cultivar Cavalier (one of the cultivars used during 2014 field re-plant). The different amounts of residue had no significant effect on percentage emergence of Cavalier. The 0% residue cover having the slightly higher germination could be because there are no physical obstructions preventing seedlings to establish. The different types of residue cover had no significant effect on the germination of annual medics, as the germination under wheat, barley, oats and medic residues did not differ from the control. The control had a slightly higher germination percentage (85%), while germination under residues was just below the recommended germination rate of 80-85%. This could be an indication of allelopathy from residues. The objective of the second supplementary study was to investigate the allelopathic effects of different residue leachates (wheat, barley, oat and medic) at different levels of concentrations (100% leachate, 75%, 50%, 25% and distilled water being the control) on Cavalier germination. The interaction between leachate type and concentration were significant. Low levels of leachate concentration did not have a significant impact on medic germination when compared between each other and the control. When the concentration percentage was increased differences were detected. Cavalier germination decreased drastically when medic leachate concentration increased, indicating allelopathic effects. Cavalier germination followed the same trend, just not as drastic, when wheat leachate concentration increased. This indicates that wheat could also have a negative allelopathic effect. With oat leachate Cavalier germination did not decrease except when 100% concentrate was used, which could indicate a small allelopathic effect. Cavalier germination following barley leachate showed no effect as concentration increased, even showing the odd increase. Depending on repeatability or follow-up studies of these experiments, data suggest that re-plant of medic pastures is beneficial if plant count drops below sustainable levels. Management of weeds during the medic pasture year improves production. Annual medic pastures should be re-planted following a cereal production year rather than a previous pasture year. Thus single medic rotations are preferred, for example WMWM rotation. Greater amounts of residues are beneficial for CA effects, but allelopathic effects of wheat and oat residues should be taken in consideration during re-establishment and residue levels should be lowered. / AFRIKAANSE OPSOMMING: Eenjarige medic weidings speel ʼn belangrike rol in bewaring landbou (CA) praktyke in die Wes Kaap, vanweë sy vermoë om jaarliks op sy eie te hervestig en sy voordelige rol in rotasie stelsels. Eenjarige medic weidings is tans die hoof kort rotasie gewas in die Overberg, maar boere is tans besig om dit uit die rotasie uit te sluit. Dit is as gevolg van lae hervestiging sowel as die opvallende afname in produksie. Hierdie waarnemings het na ʼn paar jaar na die toepassing van CA praktyke begin. Gedurende 2013 is daar ʼn veldstudie voltooi rakende medic weiding hervestiging en produksie wat na ʼn koring, gars, hawer en medic weiding produksie jaar volg (WM, BM, OM en MM). Gedurende die studie is stoppels by verskillende persentasie vlakke van bedekking op die grond gelaat (100%, 75%, 50%, 25% en 0% bedekking). Die doel van die studie was om die invloed van verskillende tipes en hoeveelhede stoppels op die hervestiging en produksie van eenjarige medic weidings vas te stel. Data van hierdie studie dui aan dat jaarlikse medic weidings so bestuur moet word dat medics in die Overberg area se plant telling nie laer as 78 plante per vierkante meter daal nie. Onkruid bestuur is van kardinale belang, omdat dit kompeteer met medics en veroorsaak ʼn verlaging in hervestiging en opbrengs. Data dui ook aan dat ʼn koring/medic stelsel die beste opsie is wanneer ʼn kort kontant gewas/eenjarige weiding gewas stelsel toegepas word. Produsente moet hul vee so bestuur dat ʼn 50 tot 75% stoppel bedekking gedurende die somer maande oorgelaat word na beweiding. Die herhaling van die 2013 veld studie was van plan, maar ag gevolg van lae hervestiging en produksie was die proef kampe oor geplant. Die veldstudie in 2014 was medic/klawer vestiging en produksie na herplanting ondersoek. Die medic/klawer saad is geplant na ʼn koring, gars, hawer en medic weiding seisoen onderskeidelik. Stoppels is weereens na verskillende bedekking persentasies verander (100%, 75%, 50%, 25% en 0% bedekking). Die doel was om te kyk wat die effek van verskillende tipes en hoeveelhede stoppels op eenjarige medic/klawer weiding is na herplant. Data wys dat medic/klawer weidings verkieslik herplant moet word na ʼn graan produksie jaar as ʼn medic weiding produksie jaar. Die medic/klawer weiding is nie geaffekteer deur die hoeveelheid stoppels op die grond oppervlakte nie, dus is ʼn 100% stoppel bedekking verkieslik vir optimale CA effekte. As diere in die sisteem teenwoordig is, kan stoppels bewei word gedurende die somer maande tot ʼn 50% bedekking bereik word. Grond sal langer vat om sy potensiaal te bereik, maar die jaarlikse bruto marge sal meer stabiel wees. Twee aanvullende studies is onderneem en ontkieming van eenjarige medics is ondersoek onder beheerde toestande. Die doelwit van die eerste aanvullende studie was om te kyk na die fisiese versperring effek van stoppels by verskillende persentasie bedekking (100%, 75%, 50%, 25% en 0%) en ʼn moontlike allelopatiese effek van verskillende tipe stoppels (koring, gars, hawer en medic) op die eenjarige medic kultivar Cavalier. Verskillende hoeveelhede stoppels het geen beduidende uitwerking op die vestiging van Cavalier gehad nie. Die 0% stoppel bedekking het ʼn effens hoër vestiging gehad. Dit kon wees as gevolg van geen fisiese versperring wat die saailing verhoed om te vestig nie. Die verskillende tipes stoppels het geen beduidende uitwerking op die ontkieming van eenjarige medics nie, die vestiging onder koring, gars, hawer en medic stoppels het nie statisties verskil van die kontrole nie. Die kontrole het wel ʼn effense hoër persentasie vestiging gehad (85%), terwyl die vestiging onder die stoppels onder die aanbevole koers van 80-85% was. Dit kan dalk ʼn allelopatiese effek van die stoppels aandui. Die doel van die tweede aanvullende studie was om die allelopatiese effek van die verskillende tipes stoppels (koring, gars, hawer en medic) by verskillende vlakke van konsentrasie (100%, 75%, 50%, 25% van die onverdunde loogsel en gedistilleerde water as kontrole) op Cavalier ontkieming. Daar was ʼn beduidende interaksie tussen tipe en konsentrasie loogsel. Met lae konsentrasie vlakke van loogsel was daar nie ʼn werklike impak op Cavalier ontkieming tussen die verkillende tipes en die kontrole nie. Slegs wanneer die konsentrasie persentasie verhoog is, is verskille waargeneem. Cavalier ontkieming het drasties af geneem soos die medic loogsel konsentrasie toegeneem het, wat ʼn negatiewe allelopatiese en verhoogde osmolaliteit effek wys. Cavalier ontkieming het dieselfde tendens gewys wanneer koring loogsel konsentrasie verhoog was, maar nie so drasties soos medic loogsel. Dit dui daarop dat koring ook ʼn negatiewe allelopatiese effek wys. Met hawer loogsel het Cavalier ontkieming slegs by die 100% konsentrasie pyl afgeneem, wat op ʼn lae allelopatiese effek dui. Cavalier ontkieming onder gars loogsel het geen verandering gewys as konsentrasies toegeneem het nie, en het selfs ʼn toename in ontkieming in party gevalle ondergaan. Afhangend van herhaling of op-volg studies van hierdie eksperimente, wys die data dat dit voordelig is om medic weidings te herplant as plant telling onder 78 plante per vierkante meter daal. Die bestuur van onkruid tydens die medic weidings jaar verbeter opbrengs. Eenjarige medic weidings moet herplant word na ʼn graan produksie jaar liewer as ʼn vorige weidings jaar. Medics moet dus in ʼn eenjarige rotasie stelsel wees, byvoorbeeld WMWM rotasie. Meer stoppels is voordelig vir CA promosie, maar allelopatiese stowwe van koring en hawer stoppels moet in ag geneem word en stoppels moet verlaag word vir hervestiging.

The act of decision making involves a choice amongst tradeoffs. In agriculture this is no different. This dissertation is composed of four papers that examine the tradeoffs being made across different agricultural decision making processes. The first two papers examine the tradeoffs made at the individual producer level while the last two papers examine tradeoffs made at the national policy level. The first paper investigates farmer attitudes towards how a hypothetical set of production practices referred to as "]conservation agriculture" will affect yield, labor use, erosion, and cost in two communities of Bolivar province, Ecuador. By evaluating the tradeoffs producers are willing to make when choosing to adopt such practices, changes in producer welfare associated with adoption may be identified. These measures can assist in identifying constraints to adoption and aid in extension and policy outreach development. The second paper aims to gain a better understanding of the dynamic relationship between farmers and food buyers. This issue is examined from the perspective of small-scale specialty crop producers who are currently or are considering marketing their products into wholesale food markets. With a focus on farms in Virginia and North Carolina, this study seeks to identify key contract characteristics and buyer attributes which are valued by small-scale specialty crop producers; quantify tradeoffs small-scale specialty crop producers are willing to make between buyer attributes and contract characteristics when establishing a new contractual relationship; and determine the factors influencing these tradeoffs. The third and fourth papers examine the demands that U.S. biofuel production has placed on domestic nutrient fertilizer production. A key argument in favor of domestic biofuel production is that it is a renewable path towards energy independence. However the inputs used in the production of biofuel feedstock, primarily fertilizer nutrients, are anything but renewable. These two papers add to the discussion surrounding biofuel policies by asking an important question that has not received the attention it deserves: "What about the non-renewable inputs (e.g., nutrient fertilizers) that go into producing the inputs (e.g., corn) used for biofuel production?" / Ph. D.

<p> Invasive phragmites (<i>Phragmites australis</i>) has encroached on the central Platte River in recent years potentially out-competing native stands of phragmites. Invasive stands are thought to have an overall negative impact on ecosystems, but do provide ecological benefits to some species as food or shelter. Little research has been conducted on its impacts on small mammals. The goals of this project were to identify potential native and invasive stands along the central Platte River and determine small mammals use of invasive phragmites. I examined 35 phragmites samples along the central Platte River using restriction fragment length polymorphism. I used molecular sequencing and morphological features to identify stands. All samples were determined to be invasive. Four study sites along the Platte River were selected to evaluate phragmites use and potential impacts on small mammals. Each study site was in a wooded grassland area and consisted of three patches of invasive phragmites and three patches of wooded grassland vegetation. Study sites were sampled using Sherman live traps from April to October 2014. I found no significant difference in overall small mammal use between vegetation types and no seasonal difference between use of phragmites and wooded grassland stands. I did, however, catch fewer individuals in both habitat types during August. Deer mice (<i> Peromyscus maniculatus</i>) selected native vegetation whereas the white-footed mouse (<i>Peromyscus leucopus</i>), meadow vole (<i>Microtus pennsylvanicus</i>) hispid cotton rat (<i>Sigmodon hispidus</i>) and meadow jumping mouse (<i>Zapus hudsonius</i>) selected phragmites. Capture of hispid cotton rat was the first documentation of this species in Dawson County, Nebraska. Differences in selection by these species could be attributed to their different life histories or habitat preferences. The focus of management for invasive phragmites may not need to focus on total eradication. Additional sampling would be required to document the spatial extent of native phragmites stands along the central Platte River.</p>

<p> For mule deer (<i>Odocoileus hemionus</i>) in the Intermountain West, alterations to habitat are outpacing strategies to mitigate human disturbance on critical seasonal ranges and migration routes. </p><p> Conserving mule deer habitat requires cooperation between a diverse group of stakeholders, state wildlife agencies, and federal land management agencies. The first chapter of this thesis explores the current and historical relationship between state wildlife agencies, citizen stakeholders, and federal agencies in order to highlight opportunities to improve cooperative habitat conservation in the United States. Conservation is a result of social, political, and economic action, but relies upon science to inform policy. The second chapter explores the seasonal habitat use of mule deer in southwestern Wyoming. In response to low fawn recruitment, the Wyoming Game and Fish Department deployed 15 GPS collars on adult female mule deer in an effort to enhance knowledge of mule deer population dynamics, migrations, and habitat use. The study captured two winter climate regimes, with greater winter severity during the 2010-11 winter compared to the winter of 2011-12. Deer migrated an average of 23.9 km (SE = 2.2) between seasonal ranges, and completed spring migrations nearly one month earlier following the milder winter of 2011-12 (<i>t</i>19 = 5.53, df = 19, <i>P</i> &le; 0.001). Pooled, the average area of winter ranges (1057 ha, SE = 103, <i>n</i> = 26) was larger than summer ranges (423 ha, SE = 51 ha, <i>n</i> = 25) (<i>t</i> = &minus;5.44, df = 49, <i>P</i> &amp;le; 0.001), with no increase or decrease in size of seasonal ranges detected between years (<i>P</i> = 0.243) according to a post-hoc Tukey HSD test. Between years, deer were observed to shift the geographic center of winter ranges (2.9 km, SE = 1.1, <i> n</i> = 12) to a larger degree than summer ranges (0.4 km, SE = 0.1, <i> n</i> = 12) (<i>t</i> = &minus;2.20, df = 22, <i>P</i> = 0.040). Survival and pregnancy rates (86% and 96%, respectively) correlated closely with other mule deer studies, and neither factor appears to negatively impact population growth. </p><p> Identifying seasonal ranges and migration routes, and quantifying seasonal habitat use, will assist Wyoming Game and Fish Department efforts to protect mule deer seasonal habitats and migration routes, and direct vegetation manipulations intended to improve the nutritional quality of habitats. On average, winter ranges included a later percentage of shrub-dominated habitat (83.8%, SE = 0.3, <i>n</i> = 26) than summer ranges (57.5%, SE = 2.0, <i> n</i> = 25) (<i>t</i> = &minus;4.42, df = 49, <i>P</i> &le; 0.001). Summer ranges averaged a greater proportion of agricultural lands (2.8%, SE = 1.1, <i>n</i> = 25) and aspen (<i>Populus tremuloides </i>) habitats (9.0%, SE = 2.2, <i>n</i> = 25) than winter ranges (0.1%, SE = 0.1, <i>n</i> = 26 and 0.2%, SE = 0.0, <i> n</i> = 26, respectively) (<i>t</i> = 3.03, df = 49, <i>P</i> = 0.004 and <i>t</i>= 3.86, df = 49, <i> P</i> &le; 0.001, respectively). Mule deer ranges are primarily located on Bureau of Land Management (73%, SE = 2.8, <i>n</i> = 51) and privately owned (17.3%, SE = 2.9, <i>n</i> = 51) lands, highlighting opportunities for cooperative partnerships for mule deer habitat conservation. </p>

<p>The Mississippi Alluvial Valley (MAV) is an important region for wintering mallards (Anas platyrhynchos) in North America, yet little is known about their spatiotemporal habitat use and related survival in Mississippi. I tracked 126 radio-marked female mallards to quantify survival, habitat use, and use of wildlife management areas (WMAs) with experimental hunt regimes in the south MAV of Mississippi during winters 2010-2012. Daily survival was greatest in agricultural (0.997) and moist-soil (0.999) habitats in winters 2010-2011 and 2011-2012, respectively. Overall interval survival across both winters was 0.60 (SE = 0.02). Forested (40-54%) and moist-soil wetlands (41-59%) received greatest use diurnally and nocturnally, respectively. Mallards used WMAs similarly (P > 0.22) whether they were hunted 2- or 4-days/week. My data suggest that complexes of flooded cropland, forest, and moist-soil habitats are suitable habitats for mallards in the MAV, WMAs can be hunted 4-days/week, and sanctuaries should be revised at two WMAs.

<p> Stocking of trout into naturally fishless water bodies in the mountains of western North America has reduced populations of many native species in those systems, with benthic aquatic invertebrates being particularly impacted. Although bats are known consumers of emergent aquatic insects, almost no studies have focused on how changes to these prey populations at lakes subsequent to trout stocking could affect them. This study assessed bat activity, foraging activity, and foraging rate at nine feature-matched pairs of stocked and unstocked high elevation lakes in the central Sierra Nevada mountains in an effort to determine which provide higher quality foraging habitat for bats. Bats in the 25 kHz and 50 kHz echolocation call categories showed little to no behavioral change between lakes with trout and lakes without. In contrast, bats in the 40 kHz group had higher levels of activity at stocked lakes, which may indicate that at those lakes bats are consuming numerous small insects. If this is the case, it could represent a cost to those bats due to the lower energetic return of small prey items compared to the preferred prey species. </p>

Thesis (M.S.) in Resource Ecomonics and Policy--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 94-100).

Thesis (M.U.R.P.)--Ball State University, 2009. / Title from PDF t.p. (viewed on July 12, 2010). Research paper (M.U.R.P.), 3 hrs. Includes bibliographical references (p. 57-60).

Based on cross-sectional data drawn from 135 treated and 68 control farmers in Tanzania, and 133 treated and 71 control farmers in Zambia, this study uses propensity score matching to test whether conservation agriculture (CA) improves smallholder farmers’ welfare, in response to the policy objective of enhancing their resilience in the face of climate change. Farmers in Tanzania assess CA as having statistically significant impacts on increasing total agricultural yield, adaptation to climate change impacts, resilience to droughts, increasing maize production, enhancing household food security, increasing number of meals per day, increasing household income, accumulation of productive assets , addressing gender disparity and social cohesion, and improving soil health . However, CA had no impact on reducing the forest area cleared per year and total agricultural costs. Farmers in Zambia assess CA as having statistically significant impacts on increasing total agricultural yield , adaptation to climate change impacts, resilience to droughts, increasing maize production, enhancing household food security, increasing number of meals per day, decreasing number of food insecure months, increasing household income, accumulation of productive assets, addressing agricultural calendar bottlenecks, increasing total agricultural costs, addressing gender disparity and social cohesion, and decreasing soil health. However, CA had no impact on reducing forest area cleared per year. Policy could use such evidence to leverage CA adoption in support of the sustainable development goals (SDGs) and Africa Agenda 2063, although its potential to sequester carbon and provide ecosystem services comes into question. / Dissertation (MSc Agric (Agricultural Economics))--University of Pretoria, 2021. / AERC-CMAAE / African Conversation Tillage Network / Agricultural Economics, Extension and Rural Development / MSc Agric (Agricultural Economics) / Unrestricted

This research identifies gender-based constraints and opportunities for the adoption of conservation agriculture production systems (CAPS) based on a case-study with smallholder farmers in two villages in Misamis Oriental, Philippines. It explores gendered soil knowledge and perceptions, access to resources, and agricultural practices in the context of food security and soil conservation. This approach combines qualitative and quantitative methods such as focus group discussions, household interviews, participatory mapping, and GPS mapping. I found that men and women have gendered soil perceptions which are linked to topography, gender roles, and access to assets.  These could have implications for whether men and women adopt conservation agriculture. I also demonstrate the importance of combining geospatial techniques and participatory methods for gender research in a development context. Much of the qualitative GIS literature focuses on incorporating qualitative data into a GIS, yet I argue it is important to incorporate geospatial tools into qualitative, participatory research to understand the spatiality of people\'s perceptions, practices, and resources. / Master of Science