<p>I investigated percent coverage, plant height, species richness, and woody stem density in plant communities in ten study plots during spring and fall (2010&ndash;2012) within 3 different treatments (continual mowings, one fall mowing, and one fall mowing with native wildflower seeds) on Highway 25 right-of-way in Oktibbeha and Winston counties, Mississippi. I recorded 277 plant species including native and non-native forbs, legumes, grasses, rushes/sedges, and woody plants. Non-native agronomic grasses exhibited greatest coverage greater than 90 percent occurring in all treatments. Percent coverage of plants less than 0.46m height category exceeded 100 while, greater than 0.46m plant height categories averaged 55 percent. Woody stem density ranged from 7,772 year 1 to 10,025 stems/hectare year 2. I detected no significant differences in plant height or woody stems among treatments. One mowing per year retained agronomic plant cover for erosion control and annual cost savings up to 75 percent for roadside maintenance. </p>

<p> The Gal&aacute;pagos Archipelago is recognized internationally as a unique eco-region, and many of the species that inhabit these islands can be found nowhere else on Earth. The Ecuadorian government recognized the value of this ecosystem, and, beginning in 1959, they designated 97% of the Archipelago as Ecuador's first National Park. The Charles Darwin Foundation also was founded in 1959 and, since then, the Park Service and the Foundation have worked towards preserving the Gal&aacute;pagos' unique flora and fauna for future generations. The waved albatross (<i>Phoebastria irrorata</i>) is the largest bird species found in the Gal&aacute;pagos Archipelago and was recognized as an iconic species early in the Park's history; it is the only tropical albatross. This species spends the majority of its life foraging at sea and is an important predator in the Humboldt Current off of the coast of South America. With the exception of a few pairs, this albatross breeds entirely on the southeastern most island of the archipelago, Espa&ntilde;ola. Tourists visit Espa&ntilde;ola every year to watch the elaborate courtship dances of this species, and albatrosses in general have been the foci of legends among sailors for centuries. </p><p> M.P. Harris (1969) began banding waved albatross as early as 1961, marking the beginning of a long-term monitoring program with a focus on estimating age-specific first-time breeding, abundance, and survival. This initial effort resulted in the first estimates of abundance and survival for the waved albatross (Harris 1973). Following these initial estimates, the population size of the waved albatross has been estimated in 1994 (Douglas 1998), 2001 (Anderson et al. 2002), and 2007 (Anderson et al. 2008). These estimates suggest that the population has been declining since 1994. Motivated by this apparent decline, Awkerman et al. (2006) investigated survival and concluded that survival estimates from 1999-2005 were lower than average survival from 1961-1970 (Harris 1973). Today, the waved albatross is considered critically endangered, with bycatch in artisanal longline fisheries and the increased occurrence of El Ni&ntilde;o-Southern Oscillation events thought to be contributing to these observed declines in survival and abundance. Given these observed declines in the waved albatross, the importance of the species in the ecosystem, and its intrinsic value in terms of biodiversity, continued monitoring and analysis efforts are needed to evaluate trends over time, and to gauge the effectiveness of management actions. My thesis is focused on these topics. </p><p> In Chapter 1:, I describe a framework to estimate abundance of wildlife populations, apply this framework to estimate population size of the waved albatross at a major breeding colony on Espa&ntilde;ola Island, and I conclude by providing recommendations for future island-wide surveys of this species. </p><p> In Chapter 2:, I revisit the dataset collected by M.P. Harris and the Gal&aacute;pagos National Park from 1961-1981 as well as a more recent dataset collected by K.P. Huyvaert and colleagues. I analyzed these datasets in a multistate mark-recapture framework to estimate and compare estimates of adult survival as well as other important demographic parameters that have not yet been evaluated for this species. </p><p> Bycatch from fisheries and extreme weather events have influenced survival and breeding probabilities of many pelagic seabird species worldwide. Lower adult survival of the waved albatross is thought to be associated with bycatch in the small-scale fishery located off of the coasts of Peru and Ecuador as well as with El Ni&ntilde;o-Southern Oscillation events. Previous efforts to document these threats have not formally considered that a variable proportion of the population does not breed every year or that different life history stages may have different survival rates. </p><p> The results from Chapter 1 suggest a continued decline in the principal breeding population of the waved albatross since 1994, and Chapter 2 shows indirect evidence that this decline may be linked to higher mortality associated with recent documented increases in small-scale longline fishing effort off of the coast of South America. Outside of the Galapagos Marine Reserve where fishing is heavily regulated by the Galapagos National Park Service, little is done to directly manage artisanal fishing operations off of the coasts of Peru and Ecuador. Conservation initiatives recognizing the environmental impact of fishing in this zone have been promoting reduction of seabird bycatch by educating local fishermen. Despite these conservation efforts, the results from my thesis suggest a continued population decline for this critically endangered species and additional mitigation may be needed for the persistence of the waved albatross.</p>

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 150-156). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 150-156). Also available on the Internet.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 130-135). Also available on the World Wide Web.

Maize is a staple crop and underpins food security for Zambia. Maize productivity in Zambia is almost half the potential due to low uptake of conservation agricultural practices. This study tests the hypothesis of the trade-offs between agriculture productivity and long-term ecosystem services (ES) provision among maize farmers practising conventional agriculture on the one hand, and those practising conservation agriculture on the other hand, in Kafue district, Zambia. In addition, challenges which affect conservation agriculture uptake are assessed. Besides these challenges, the study notes that adoption of a new technology is also influenced by its efficiency, and therefore technical efficiency scores were estimated using the Stochastic Frontier Approach (SFA) to compare efficiency levels of the two agricultural systems. Kafue was purposefully selected as it is among the first districts where conservation agriculture was introduced. Through purposive and random sampling, the households surveyed were split into two distinct groups namely conservation agriculture (CA) farmers (treatment group) and conventional agriculture (CV) farmers (control group). The analysis significantly shows that farmers practicing CA have more knowledge than CV farmers about the capacity of conservation agriculture to reduce soil erosion, increase soil fertility, retain nutrients, mitigate pests and weeds and increase crop yield. However, both farming groups knew that CA helps conserve soils and that soil maintenance is important for food production. On the other hand, significantly, CV farmers knew more than CA farmers that CV reduces crop yield and increases soil erosion. On the other hand, CV farmers expressed a higher level of willingness to adopt CA practices than CA farmers who are unwilling to expand their area under CA. The study further shows that at least 55% of farmers practicing CA find inadequate labour to be the main challenge faced in CA. It appears that a policy that improves the farmers' knowledge on CA would help improve the uptake of CA. CA farmers were significantly more knowledgeable than CV farmers about the detrimental effects of CV, such as increasing air and water pollution, thus raising the need for training among CV farmers with emphasis on the effects of their farming system on the environment which affect the supply of ecosystem services. Efficiency is also a means of improving productivity hence the Stochastic Frontier Analysis (SFA) was employed to estimate technical efficiency levels in maize production. Using SFA, the study found that the technical efficiency of maize among CV farmers is 71.3% on average while that of CA farmers is 57.9% on average. Moreover, the study found that there was a significant difference (t=3.9854, P=0.0002) in the technical efficiency scores of the both CV and CA farmers. Nevertheless, the study also found that 77% of output variation among CA farmers can be explained by variation in technical efficiency. However, 33.4 % of total maize output can be explained by variation in technical efficiency among CV farmers. This means that CA farmers have a higher potential to increase their current output than CV farmers. Finally there was no significant difference in fertiliser usage between CA and CV farmers (t=1.3825, P=0.1700). Further, from SFA fertiliser responsiveness to maize output showed that a 1% increase in the use of synthetic fertiliser leads to 0.678% and 0% increase in maize output per hectare for CA and CV respectively at both 1% and 10% level of significance at the expense of water and air quality. Therefore, it can be concluded that there is a higher trade-off between maize production and water and air quality under conventional than under conservation agriculture. / Dissertation (MSc (Agric))--University of Pretoria, 2016. / Agricultural Economics, Extension and Rural Development / MSc (Agric) / Unrestricted

Situated on the western edge of Africa's harsh Sahel region, Senegal faces a number of agricultural production constraints. Limited rainfall, poor soil fertility, and insufficient agronomic inputs all contribute to low yielding millet production systems. This study was initiated to assess the potential for intercropping either cowpea (Vigna unguiculata (L.) Walp.) or mungbean (Vigna radiata (L.) Wilczek) into traditional pearl millet (Pennisetum glaucum (L.) R. Br.) cropping systems. During the 2013 and 2014 growing seasons two varieties of cowpea (upright and viney), and one variety of mungbean (upright) were grown in monoculture and subsequently intercropped with millet to evaluate the potential for increasing millet and overall yields. Millet was also planted with a mulch (2 t/ha of neem leaves) to test the effectiveness of increased ground cover on millet yields. In addition to yield data, soil moisture and plant NDVI data were also collected. Millet grain yields increased when intercropped with either cowpea or mungbean compared to millet that was grown alone, with grain yield increases of up to 55%. Additionally, the combined grain yields (millet + bean) were up to 67% higher than the traditional monoculture millet. The addition of mulch was the most effective treatment and increased millet grain yields up to 70%. Soil moisture increased up to 14% in mulched treatments over millet monoculture treatments. All yield increases were achieved without the addition of fertilizers or nutrient amendments. In an attempt to mimic local practices our experiment was rainfed and no soil amendments were introduced. / Master of Science

Conservation agriculture has many potential benefits for small farmers. This study seeks to estimate the value that farmers in eastern Uganda place on some these benefits. Data from a choice experiment study are analyzed with a mixed logit model to determine farmers' willingness to pay for increases in maize yield, reductions in erosion, and reductions in land preparation labor requirements. It finds that farmers have a statistically significant willingness to pay for increases in yield and reductions in erosion, but not for reductions in planting labor. In addition, farmers in Kapchorwa district value erosion control and labor reductions more and price increases less than in Tororo district, while women care more about price increases than men do. / Master of Science / CCRA-6 (Economic and Impact Analysis)

This research investigates gender-based constraints and opportunities to the dissemination of conservation agriculture based on a case study with smallholder farmers in the village of Pichangva, Rattanakmondol, Battambang Province, Royal Kingdom of Cambodia. Using qualitative and quantitative methods, including focus group discussions, semi-structured interviews, household surveys, and participatory mapping, we explore the effect of conservation agriculture on men's and women's allocation of labor, gendered power relations in intra-household negotiations, and access to resources and information. I found that conservation agriculture has the potential to decrease men's and women's workload and drudgery in cash crop production and generates opportunities for other work; however, this may contribute to an increase in women's "triple workload" as they invest part of this "extra time" in additional domestic and community responsibilities. I also found that gender intersects with other factors to limit men's and women's access to and control over resources, access to information, and participation in household negotiations. These findings could have implications on smallholder farmers' decision to experiment with conservation agriculture. / Master of Science / CCRA-7 (Gendered Knowledge)

While extensive research has been carried out to examine the yield growth brought about by innovations in agricultural technology, not enough work has been done to document the economic impacts of these innovations on areas besides yields and income. This study presents two papers which contribute to our understanding of the health and environmental impacts of agricultural innovation, "Expected economic benefits of meeting nutritional needs through biofortified cassava in Nigeria and Kenya," and "Projected farm-level impacts on income of conservation agriculture in the Andean Region." The first paper is motivated by the public health consequences of vitamin and mineral deficiencies, which affect more than two billion people worldwide and can lead to increased incidence of illness, disability, and mortality. Through the use of the disability adjusted life years concept (DALYs), economic surplus analysis, and benefit-cost analysis, the authors determine the economic impact of a staple crop biofortification project. The study finds that biofortified cassava in Nigeria and Kenya is a cost effective means of reducing health problems associated with vitamin A and iron deficiency. The second paper considers the significant livelihood challenges faced by rural communities in the Andes, including poverty, food insecurity, and natural resource constraints. Through the development and implementation of a linear programming model, the study analyzes the economic impact of a conservation agriculture project in central Ecuador, and finds that certain experimental cropping activities designed to decrease soil degradation may contribute to increased incomes for farm households. / Master of Science