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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effects of grazing cover crops on animal performance, soil characteristics, and subsequent soybean production in east-central Mississippi

Bass, Bronson Scott 10 December 2021 (has links) (PDF)
Integrated crop-livestock systems (ICLS) incorporate cropping systems and livestock production by grazing cover crops. With a growing awareness in recent years regarding agricultural sustainability, these systems have begun to be re-introduced into the southeastern U.S. This study evaluated cover cropping systems under grazed no-till (GNT), un-grazed no-till (UNT), and un-grazed conventional tillage (UCT) management, in Mississippi. Beef cattle (Bos spp.) performance was significantly less in the cover crop treatment of oats (Avena sativa) + crimson clover (Trifolium incarnatum) + radish (Raphanus sativus; OCR) in both average daily gain (ADG; 3.03 lb hd-1 d-1) and total gain ac-1 (GAIN; 346 lb ac-1). Soybean (Glycine max) yield was unaffected by cover crop treatment and tillage. The lowest expected economic return was generated by OCR ($749.31 ac-1). Soil penetration resistance was unaffected by the influence of grazing. The greatest concentrations of soil organic carbon (1.44%) and soil nitrogen (0.20%) were observed in GNT.
2

Analysis of the livestock production system of the Poroma community in the 2 section of the Oropeza province, department of Chuquisaca

Ramí­rez Serrudo, Freddy Claudio 01 January 2000 (has links) (PDF)
This study was performed in the Poroma community of the Oropeza Province, in the department of Chuquisaca. The Poroma community is characterized by a high poverty level among its members due to a number of different factors. Some of the major factors include: a restricted market, small farms, an absence of support systems, and a lack of support for agricultural development. This lack of support is seen in areas such as: research, roads, electricity, technical assistance, marketing systems, organization, and institutions that support rural development. Numerous studies on the production systems of farmers have described and analyzed the agricultural components but ignored the part livestock plays in the development of a rural production system. Due to this situation, this study has placed priority on the study of the livestock production system in the Poroma community. The objectives of this study are: to characterize and identify the components of the livestock production system; to establish the internal relations of the livestock production system; and to establish the relation between the livestock system and other systems present in the community. In order to accomplish the mentioned objectives, the participative research method was applied. The methods used are: Macro planning (participative prediagnosis) followed by case studies (micro planning). The techniques used to collect data are characterized as participatory. With these, we plan to involve farmers in the study. Some of the most important things are family and community workshops, participant observation, and informal discussions. The study investigated components of the livestock system such as: management, food, health, and production. Animal handling was observed to be completely free, like mating or birth, with men intervening very little in comparison to practices such as castration, branding, and grazing. The predominant race is the Creole. Delivery times are concentrated between the months of June and August (dry season) and November to December (rainy season). The main food source is the mountain where native species are used in regeneration. In general, the animals are browsers and the supplements provided are salt and bran. Only a few families control the health of their animals while the majority of families don’t control their health at all. This means that many problems exist with animal disease. The most common diseases in animals are: cattle: foot and mouth disease, anthrax, and diarrhea; sheep and goats: coenurosis; mules: angina; pigs: external parasites and cysticercosis; and birds: diarrhea. With respect to external parasites, the most severe in all the species are ticks and lice. The infrastructure for the animals in this area is not recommended because it does not offer the health conditions for their rusticity, let alone protect them from inclement weather. The products of the livestock system such as milk, meat, leather, manure, etc. are more commonly used for family consumption than for sale. The revenue earned by community members for this service is regular and is obtained at certain times of the year. Generally, they receive it at the beginning and end of each year as well as at fairs that are held in the area.
3

Factors influencing choices of grazing lands made by livestock keepers in Enhlanokhombe in Ukhahlamba (Drakensberg), KwaZulu-Natal.

Chonco, Johannes Mphumzeni. January 2009 (has links)
In South Africa, communal land still plays a significant role in the lives of many rural communities. While these communal lands have ostensibly been included within municipal frameworks, decisions about their utilisation still remains a practical reality for many livestock keepers. This research examined current herding and grazing practices, grazing areas being used in summer and winter, and factors taken into consideration by livestock keepers and herders when choosing grazing areas in the communal sub-ward of Okhombe, in the northern Drakensberg, KwaZulu-Natal. The aim of this research was to investigate the socio-cultural reasons of livestock keepers behind decision making about grazing areas. The primary research question pursued in the study was: How do livestock keepers select areas for livestock grazing in the sub-ward? Three sub-questions were developed to guide the research: What grazing and herding strategies are currently being used? Which areas are used for grazing, and in which season(s)? What are the considerations for choosing areas for livestock grazing? Data were collected from fifty-one (51) cattle keeping households in the sub-ward. Data were collected in five steps. The first two steps involved household and in-depth interviews using interview guides. The latter three steps involved a transect walks, one case study and focus group discussions to test and verify the data. The findings showed a wide range of livestock kept in Enhlanokhombe sub-ward. The majority (61%) of cattle keeping households had cattle and goats, which are important for ceremonial purposes. The primary reasons for keeping livestock involved agricultural, food and cultural purposes. The herding strategies found in the sub-ward involved family/relative member, hired herders and no herder, with the majority using family/relative members as herders. Three areas were used for livestock grazing were Maqoqa, Skidi and Mdlankomo. The key finding showed an increase in supplementary feeding, a decrease in traditional remedy usage and safety from theft as a new factor taken into consideration when selecting grazing land. Other factors involved presence of cropping fields, availability of grass and water, distance from home and family traditions. From these findings, one can conclude that there are clearly tensions between culture and changes in the society, culture and changes in economy; and livestock keepers' heritage and modern lifestyle. These tensions make livestock keepers' decision making processes harder. The grazing and herding strategies, and the choices of communal grazing areas are influenced by these changes. As a result, livestock keepers are shifting from their heritage and culture to being economic and adapting to modern world. The heritage and the clarity of gender roles are breaking down. Grazing and herding are, therefore, no longer simple and familiar, but complex and unfamiliar to livestock keepers. These findings have serious implications for extension, advisory and development approaches used when addressing livestock management among traditional livestock keepers. They imply that what is needed is a multi-dimensional and inclusive view of the livestock keepers' practices. Rather than relying on the long-held assumptions about livestock keepers, serious attention must be given to the tensions in communal livestock keeping and the complexity of communal grazing strategies. These must be deliberately and consciously used to inform interventions designed to improve communal grazing management. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
4

Evaluation of improved Brachiaria grasses in low rainfall and aluminium toxicity prone areas of Rwanda.

Mutimura, Mupenzi. January 2010 (has links)
Abstract available in the print copy. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
5

The Livestock Improvement Scheme in the Eastern Cape: experiences of small farmers in Elliot

Nompekela, Zikhona January 2016 (has links)
This study was motivated by the realisation that the Eastern Cape Province is a leading producer of cattle, but few to none of those cattle makes it to auction markets. The study was conducted in the Elliot area, selected as an area with a high number of Land Redistribution for Agricultural Development farms, as well as private farms and communal farmers. Most of these farmers battled to sell their cattle to the auctions or abattoirs. The objective of the study was therefore to investigate challenges facing smallholder beef cattle famers and those factors which prevented them to access auction markets to sell their cattle in the Elliot area. The second was to assess the effectiveness of the Livestock Improvement Scheme in support of smallholder beef cattle farmers in terms of the outcome and achievements of training these individuals to become successful farmers. The last was to find out how beef cattle farmers benefited from the scheme. Both semi-structured interviews and an open-ended questionnaire were used to collect data. A sample size of 10 farmers (eight farmers from LRAD/private and two from communal farmers) was selected, and observation was done on the auctions and abattoirs available in Elliot. The study found that smallholder cattle farmers struggle to sell their stock through formal and informal markets, as they are faced with marketing constraints.Such marketing constrainst are lack of marketing information, drought, poor condition of cattle, lack of infrastructure, shortage of land for grazing, price takers, stock theft, transaction costs, problems with cattle identification, and lack of physical access to markets. The study has also made recommendations on how smallholder cattle farmers of Elliot can be developed to procure markets to sell their stock.
6

Production and economics of Arado and Barka cattle in Eritrea.

Tedla, Rezene Teweldemedhine. January 2007 (has links)
Grazing lands in Eritrea are degraded due to decades of overstocking and consequent overgrazing. Since the rangelands are accessible to entire village communities, organisation and coordinated decision making regarding the management of these resources is not often achieved. Farmers are not motivated enough to make investments to improve a communally owned resource due to the prevailing common access grazing systems. A field survey was undertaken interviewing 12 farmers in the private access commercial and 80 farmers in the common access subsistence grazing using face to face interviews in the Barka and Arado cattle farming communities in four out of the six regions in Eritrea. Debub, Gash-Barka, S. Keih Bahri and Maekel regions were selected using stratified and simple random sampling methods. The regions were chosen based on various agroecological zones where the representatives of different grass species and the two most common cattle breeds in Eritrea (Arado and Barka) are found. The survey included the collection of data on village and household characteristics focusing on rangeland grazing management systems and additional sources of supplementary forage. The study uses several stages of analysis like principal component analysis accompanied by regression analysis together with descriptive statistics and ordination diagram. The commercial farmers addressed grazing constraints by investing in improved grazing through planting 258 ha per farmer of drought resistant seeds and 1767 vs. 8 cactus slices per farmer and covered 75% vs. 40% of forage requirements from grazing resources compared to the subsistence farmers, respectively, during 2002. These results were achieved because 78% of the commercial farmers adopted controlled stocking rates. In common access grazing, the costs of collective action to control cattle stocking rates are high, making imple mentation of stocking rate controls difficult. As a consequence, 65% of the subsistence farmers were forced to migrate their cattle looking for grazing forage in the dry season during the year. The outcomes of migration were evidenced by the results of severe overgrazing and degradation on the rangelands proximity to villages in Debub and Maekel regions and the populated area of Gash_Barka region. The increased number of animals resulting in high grazing pressure was the consequence of migration. Ten vs. six percent of mortality rates was reported for the subsistence systems compared to the commercial systems respectively. The lower results of milk yield, calving rates and off- take rate productivity indicated in the different stages of analysis for the subsistence farmers were the consequences of the lack of the adoption of controlled stocking rates primarily constrained by the migration. The Barka and Arado cattle farming systems are kept under common access grazing systems. Compared to the Arado cattle farming, the Barka cattle farming region had relatively better access to grazing forage. The better quality of grazing in this region is attributed to a naturally low stock density in the region. During 2002, the Barka cattle farming had 1087 vs. 721 Lit of milk yield, 63% vs. 53% of calving productivity and 9.3% vs. 10.9% of mortality rates than the Arado cattle farming regions respectively, due to access to a wider area of grazing lands and more labour inputs. The Barka cattle area farmers are agro pastoralists and usually focus on grazing dairy cattle farming than crop farming. They increased calving rate productivity and decreased mortality rates by increasing the proportion of lactating cows and decreasing the proportion of oxen compared to the Arado cattle farming. The Arado cattle farming had higher offtake rates and income from cattle sales compared to the Barka cattle farming region. The higher off- take rate, which is an index of percentage of cattle sold, for the Arado cattle was probably linked to the shortage of grazing forage and increased herding costs. The Barka and Arado cattle farmers had a shortage of quality and quantity crop residue winter forage during 2002. Farmers were dependent only on rain fed cropping. The application of crop rotation, fallow and chemical fertilizers were low to enhance soil nutrients. Out of the total crop residues forage produced, only 22% and 15% of legumes residue DM forage was produced for the Barka and Arado cattle farmers respectively. Agro- industrial and crop farming by-products supplementary feeds were also limited due to the shortage of feeds in the country during the year. In general, government intervention is important to bring institutional changes to promote the adoption of controlled stocking rates to alleviate the shortage of grazing forage. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.
7

Cattle and veld interactions at the Armoedsvlakte Research Station.

Le Roux, Gustav Nic. January 2011 (has links)
A long-term grazing trial was started in 1977 at Armoedsvlakte Research Station, about 10km west of Vryburg, in Tarchonanthus veld of the Ghaap’s Plateau, which is a variation of the Kalahari Thornveld veld type. The main aim of this study was to use the extensive veld condition and animal production data set to investigate the effects and interactions of stocking rate, grazing system applied and seasonal rainfall on veld condition and cattle production. The grazing trial has changed three times since its inception resulting in three different phases. The main changes in veld condition during phase one (1977-1991) was due to density independent effects (e.g. seasonal rainfall) and not density dependent effects (e.g. stocking rate). A major change occurred in 1985 following a multiple year drought. The drought resulted in adverse changes in species composition, basal cover and residual biomass of all treatments. The system did not recover from the drought during phase one, despite well above mean seasonal rainfall for a number of years after the drought. During phase two (1992-1999) and phase three (2000 to present) completely different vegetation dynamics occurred than what was experienced during phase one. Density dependent effects (e.g. stocking rate) were more important in explaining variation in veld condition during these two phases. High stocking rates resulted in adverse changes in species composition, poor basal cover and a low residual biomass production. It is however important to note that seasonal rainfall did explain a significant additional amount of variation in veld condition. This suggests that a continuum of non-equilibrium and equilibrium vegetation dynamics occurred in these two phases. The residual biomass and seasonal rainfall model for phase one indicate completely different results for the gain per animal data. In the seasonal rainfall model, stocking rate does not have a significant effect on gain per animal, but seasonal rainfall and the interaction of stocking rate with seasonal rainfall explains most of the variation in gain per animal. This suggest a continuum of non-equilibrium and equilibrium dynamics and that animal production is more sensitive to seasonal rainfall than to stocking rate, although the significant interaction of stocking rate with seasonal rainfall suggest that the seasonal rainfall effect on animal production is dependant on stocking rate. The residual biomass model however indicates that stocking rate is more important than rainfall in explaining variation in the mass gains per animal. The stocking rate effect on gain per animal was significant and indicated that as stocking rate increased, that gain per animal decreases. Seasonal rainfall and the interaction of stocking rate with seasonal rainfall had no significant effect on gain per animal. The amount of variation explained by the seasonal rainfall model was larger than the residual biomass model and this indicates that rainfall explains more variation in gain per animal, than residual biomass does. This possibly indicates that non-equilibrium effects are stronger than the equilibrium effects, but it is important to notice that stocking rate had a significant effect in some cases. The gain per hectare models (seasonal rainfall and residual biomass) for phase one indicates that stocking rate has a significant effect on gain per hectare. Increasing stocking rates resulted in higher gain per hectare, which suggests that the turning point of the typical “Jones and Sandland model” has not been reached and this might be due to light stocking rates applied during the duration of phase one. The seasonal rainfall model however has significant effects of seasonal rainfall and interactions of stocking rate with seasonal rainfall on gain per hectare. This suggests that the effect of stocking rate is dependent on seasonal rainfall and that seasonal rainfall explain an additional amount of variation in gain per hectare. In general, it appreared that the optimal stocking rate for animal production was higher than those applied during the duration of the trial, but this is due to lower than planned actual stocking rates applied during all three phases of the trial. It is very difficult to determine a generic optimal stocking rate for different rainfall volumes and it is recommended that the actual stocking rate for different ecological zones be determined based on rainfall, biomass, species compos[i]tion, basal cover and available browse and not just on the provisional recommendations. The type of grazing system applied did not show any statistically significant effects on both gain per animal and gain per hectare for the animal production data during phase one. This result is interesting and contradictive to most of the scientific literature where some authors concluded from their studies that rotational grazing systems produce higher animal production than continuous grazing systems, whereas others researchers state that continuous grazing systems produce higher animal production than rotational grazing systems. In phase two both the residual biomass and seasonal rainfall models for phase two did not show any significant effects and interactions of stocking rate, seasonal rainfall level and/or residual biomass on both gain per animal and gain per hectare. Both the residual biomass and seasonal rainfall models for phase three did not show any significant effects and interactions of stocking rate, seasonal rainfall level and/or residual biomass on animal gains per animal. The seasonal rainfall model did not show any any significant effects and interactions of stocking rate, seasonal rainfall level and/or residual biomass on animal gains per hectare. However, the residual biomass model indicated that stocking rate had a significant effect on gain per hectare and the production closely followed the Jones and Sandland (1974) model as at low stocking rates, gain per hectare increases at a rapid rate, but as stocking rates increases to high stocking rates, the rate of increase in gain per hectare declines, until it eventually reaches a turning point, where after gain per hectare declines with increasing stocking rates. Stocking rate only had a significant effect on the condition score of cows during phase two and phase three, as high stocking rates resulted in poor animal condition in both phases. No significant effects and interactions of stocking rate and seasonal rainfall were indicated on calving percentage, weaning percentage, conception rates and percentage of desirable meat produced during phase two. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, [2011].
8

ESTRATÉGIAS DE AGRICULTURA DE PRECISÃO PARA DEFINIÇÃO DE ZONAS DE MANEJO EM SISTEMAS DE INTEGRAÇÃO LAVOURA PECUÁRIA / STRATEGIES OF PRECISION AGRICULTURE FOR DEFINING MANAGEMENT ZONES CROP IN LIVESTOCK SYSTEMS

Pilon, Marcelo 05 June 2014 (has links)
The Precision Agriculture is a great tool to assist and enhance the spatial and temporal management of agricultural activities. In this sense the site-specific management, provides an understanding of agricultural crops or livestock on smaller spatial scales than those adopted in conventional agriculture. For data acquisition and obtaining maps, the Electrical Conductivity of the soil, the Penetration Resistance and Chemical Analysis of the Soil were used because they are variables which correlate with factors for grain production. This study evaluated the data obtained in a reference unit of Embrapa, submitted to a system of long-term crop-livestock integration succeeded by soybean cultivation during the summer and ryegrass pasture during the winter. The data on variability obtained on soybean yield, were used to establish management zones in pasture productivity, along with the (EC), (PR) and (CAS). From the values of correlation between soybean yield and forage production presented, it was observed that there was a positive correlation between the productivity of soybean and the forage production, only in the first cut of the forage. This result demonstrates that the response in productivity of different crops is distinct in the same area. Considering the results, it is concluded that the EC measures showed good repeatability, with a strong positive correlation with relatively small scattering. On the other hand, the areas of EC were not effective to determine the areas of management in the pasture phase, still fitting complementary studies to verify the efficiency of the EC in relation to variability in pasture productivity in southern Brazil. / A Agricultura de Precisão é uma excelente ferramenta para auxiliar e aprimorar o gerenciamento espacial e temporal das atividades agrícolas. Nesse sentido o manejo sítio-específico, proporciona o entendimento de lavouras agrícolas ou pecuárias em escalas espaciais menores do que aquelas adotadas na agricultura convencional. Para a aquisição de dados e obtenção de mapas, a Condutividade Elétrica do Solo, a Resistência a Penetração e a Análise Química do Solo, foram utilizadas por serem variáveis que se correlacionam com fatores de produção dos grãos. O presente trabalho avaliou os dados obtidos em uma unidade de referência da Embrapa, submetida a um sistema de integração lavoura-pecuária de longa duração com sucessão de cultivo de soja durante o verão e de pastagem de azevém durante o inverno. Os dados relativos à variabilidade obtida na produtividade da soja, foram utilizados para tentar estabelecer zonas de manejo na produtividade da pastagem, juntamente com a (CE), (RP) e (AQS). A partir dos valores de correlação entre a produtividade da soja e a produção de forragem apresentados, foi observado que houve correlação positiva da produtividade da soja com a produção de forragem, apenas no primeiro corte da forragem. Este resultado demonstra que a resposta em produtividade de culturas diferentes é distinta em uma mesma área. Tendo em vista os resultados obtidos, conclui-se que as medidas de (CE) apresentaram boa repetibilidade, com forte correlação positiva e com espalhamento relativamente pequeno. Por outro lado, as zonas de (CE) não foram correlacionadas para determinar as zonas de manejo na fase da pastagem, cabendo ainda estudos complementares para verificar a eficiência da (CE) em relação à variabilidade na produtividade do pasto na região sul do Brasil.
9

Modélisation multi-agents et pluri-niveaux de la réorganisation du cycle de l’azote dans des systèmes agro-sylvo-pastoraux en transition : le cas du bassin arachidier au Sénégal / Multi-agent and multi-level modelling of the nitrogen cycle reorganisation in agro-sylvo-pastoral systems in transition : the case of the groundnut basin in Senegal

Grillot, Myriam 16 March 2018 (has links)
Les systèmes agro-sylvo-pastoraux (SASP) d’Afrique de l’Ouest sont des agro-écosystèmes limités en biomasses et en nutriments. Le recyclage des nutriments et les transferts de fertilité sont traditionnellement rythmés par la mobilité des troupeaux de ruminants conduits en extensif. Les agro-éleveurs pratiquent le parcage nocturne de leurs troupeaux pour concentrer la matière organique, dans les champs à proximité des habitations afin de sécuriser une production vivrière suffisante à leurs besoins. Dans un contexte de croissance démographique et de réduction des parcours naturels au profit des zones cultivées, le système d’élevage « traditionnel », basé sur une forte mobilité intra-terroir villageois, est remis en cause. Les stratégies adoptées par les agro-éleveurs sont, soit (i) l’éloignement des troupeaux du terroir villageois pendant des périodes plus ou moins longues par des pratiques de transhumance saisonnière vers des régions moins peuplées et disposant de davantage de ressources fourragères ; soit (ii) plus récemment, des pratiques d’intensification avec des animaux gardés à l’étable au sein du terroir villageois et nourris avec des aliments concentrés, achetés sur le marché local. Ces changements de systèmes d’élevage ont possiblement des conséquences importantes sur les flux de biomasses et les cycles des nutriments au niveau du ménage et du territoire. Il convenait de les évaluer en termes d’impacts sur le fonctionnement et la durabilité des SASP. A cet effet, le modèle multi-agents TERROIR a été développé et implémenté sur la plateforme de modélisation GAMA. Il simule l’effet de changements dans l’organisation du paysage et des systèmes d’élevage sur les flux de biomasse et d’azote aux différents niveaux d’organisation du territoire : la parcelle, le troupeau, le ménage et le terroir villageois. Le modèle simule les échanges de biomasses entre une centaine de ménages comportant des stratégies et des pratiques différentes. Cela inclut les transferts spatiaux de biomasses orchestrés par plusieurs centaines de troupeaux se déplaçant de façon indépendante sur un millier de parcelles. Le modèle synthétise ces flux par un ensemble d’indicateurs issus de deux méthodes d’analyse (« Ecological Network Analysis » et « System Gate Balance ») pour décrire la structure, le fonctionnement et la durabilité de l’agroécosystème, en termes de productivité, d’efficience, d’autonomie, de recyclage, de transferts spatiaux et de bilan de nutriments. Le modèle a été conçu et paramétré à partir des données disponibles sur les agroécosystèmes de savane en Afrique de l’Ouest et il a été évalué à partir des données observées dans deux terroirs villageois du bassin Arachidier au Sénégal où les pratiques des agro-éleveurs sont particulièrement contrastées.Le modèle TERROIR a été utilisé pour explorer les impacts des dynamiques territoriales observées sur la période 1920-2015 dans le bassin Arachidier au Sénégal, une zone agricole à transition agraire rapide et avancée. Les résultats soulignent une réorganisation du cycle de l’azote et une tendance générale à l’intensification des flux et à l’augmentation de la dépendance des agroécosystèmes vis-à-vis de sources extérieures de nutriments. Cependant, le recyclage et les transferts spatiaux de nutriments internes aux agrosystèmes restent à des niveaux élevés. L’intégration sol-plantes-animaux-hommes et l’hétérogénéité spatiale de la répartition des ressources fertilisantes apparaissent comme deux propriétés persistantes des agro-écosystèmes étudiés. Consolider cette intégration et cette organisation spatiale seraient ainsi un gage pour la durabilité des futurs systèmes agricoles qui émergeront dans un contexte de poursuite de la forte croissance démographique et de changement climatique. / Agro-sylvo-pastoral systems (systèmes agro-sylvo-pastoraux - SASP) of West Africa are agroecosystems limited in biomass and nutrients. Nutrient recycling and fertility transfer are traditionally driven by the mobility of ruminant herds led in extensive practices. Agro-pastoralists practice night corralling of their herds to concentrate the organic matter in the fields near the houses, in order to secure a sufficient food production for their needs. In a context of demographic growth and the reduction of natural rangelands in favor of cultivated areas, the "traditional" mobile livestock system, based on high mobility within the village is being called into question. The strategies adopted by the agro-pastoralists are: (i) keeping the herds away from the village for periods of varying lengths, by seasonal transhumance in less populated regions where forage resources are more important, or (ii) more recently, intensified practices with animals kept in the barn within the village and fed with concentrate feeds, bought on the local markets. These changes in livestock systems may have important consequences for biomass flows and nutrient cycling at the household and village landscape level. There was a need to assess their impact on the functioning and sustainability of SASP.To this end, the TERROIR multi-agent model has been developed and implemented on the GAMA modeling platform. It simulates the effect of changes in the organization of the landscape and livestock systems on biomass and nitrogen flows at different levels of organization in the village: plot, herd, household, village landscape. The model simulates the exchanges of biomasses between dozens of households with different strategies and practices. It includes the spatial transfers of biomasses between several hundred plots orchestrated by dozens of herds moving independently. The model synthesizes these flows with a set of indicators from two methods of analysis (Ecological Network Analysis and System Gate Balance) to describe the structure, functioning and sustainability of the agroecosystem, in terms of productivity, efficiency, autonomy, recycling, spatial transfers and nutrient balance. The model was designed and configured with available data on savannah agroecosystems in West Africa. It was evaluated from data observed in two villages of the Groundnut Basin in Senegal where the practices of agro-pastoralists are particularly contrasted. The TERROIR model was developed and implemented to explore the impacts of the village dynamics observed over the period 1920-2015 in the Groundnut Basin in Senegal, an agricultural zone in fast and advanced agrarian transition. The results highlight a reorganization of the nitrogen cycle and a general trend towards increased flows and increased dependence of agroecosystems on external sources of nutrients. However, the recycling and spatial transfers of nutrients internal to agroecosystems remain at high levels. The soil-plant-animal-human integration and the spatial heterogeneity of the distribution of fertilizing resources appear as two persistent properties of the studied agro-ecosystems. Consolidating this integration and spatial organization could guarantee for the sustainability of future farming systems that will emerge in a context of continued high-population growth and climate change.
10

Towards livelihoods security : livelihoods opportunities and challenges in Embui, Kenya

Mwasaa, Walter Mbele 06 February 2013 (has links)
Given the livelihoods challenges which face many rural communities, understanding a community’s livelihoods dynamics and opportunities is one major step to developing workable options to address the challenges. This study has focused on one rural community and used the five determinants of the Sustainable Livelihoods Approach to describe the livelihoods situation in Embui sub-location in Machakos County, Kenya. Residents of Embui have had to deal with the fact that traditional production systems are not sufficient to provide for their livelihoods needs. The community and continues to be challenged by limited capital for diversifying income sources, low skills and limited social and economic services. This study recommends support to marketing of locally produced artifacts, improved access to capital and provision of water for irrigation along with extension services as the key areas of support to improve the living standards of the residents of Embui / Development Studies / M.A. (Development Studies)

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