O objetivo do trabalho foi realizar uma análise econômica e de risco em sistemas integrados de produção agropecuária (SIPA) e de bovinos de corte de ciclo completo na Campanha Meridional do Rio Grande do Sul, região sul do Brasil, por um modelo de simulação. O modelo foi desenvolvido e operado em planilhas dinâmicas do Microsoft Excel®. O trabalho foi dividido em duas etapas, na primeira, foi realizada uma identificação e análise dos riscos existentes na produção de bovinos de corte e SIPA. Na segunda, foi realizada uma análise econômica e uma avaliação dos riscos de três sistemas de produção. Como resultado da primeira etapa, os principais fatores de risco na bovinocultura foram, condições climáticas, custo de produção, capacidade de investimento e gestão da propriedade. Na SIPA foram identificados novos ricos, como a produtividade da soja (Glycine max) e desconhecimento da atividade. No entanto, do total dos riscos considerados mais importantes, metade deles estão presentes nas duas atividades. Na segunda etapa, foram estabelecidos três sistemas de produção, bovinocultura de corte de ciclo completo (SBC), bovinocultura de corte de ciclo completo associado com leasing de uma área para soja (SLS) e bovinocultura de corte de ciclo completo com o cultivo de soja pelo próprio pecuarista (SCS). O sistema que apresentou maior margem bruta foi o SLS (R$ 223,57/ha) comparado aos outros dois sistemas (SBC: R$ 138,11/ha; SCS: R$ 149,62/ha). O SCS apresentou o maior risco entre os sistemas, devido a maior amplitude de resultados na margem bruta. A produtividade média da pecuária foi similar nos sistemas SBC e SLS (129,55 e 131,74 kg PV/ha/ano). Com exceção da produtividade da soja que foi o principal risco no SBS, todos os outros estiveram ligados as fontes de risco de mercado. Conclui-se que os produtores rurais percebem o SIPA com maior risco do que a bovinocultura. Em ambos os casos, o risco de produção é o que apresenta o maior número de fatores com alto risco de ocorrência e, portanto, deve receber especial atenção pelos produtores rurais. O que foi consolidado quando se concluiu que o melhor sistema foi o SLS por apresentar melhor margem bruta e menor risco que o SCS, e este último foi o que apresentou o maior risco, no entanto, os riscos que mais influenciaram a variação da margem bruta foram os de mercado e não os de produção. / The aim of this study was compare the economic and risk analysis on an integrated crop-livestock (ICLS) and a cycle complete beef cattle systems in the Campanha Meridional of Rio Grande do Sul, Brazilian Southern Region, through a simulation model. The simulation model was developed and operated through Microsoft Excel® dynamic worksheets. The research was divided in two stages, in the first, an identification and analysis of the existing risks in the production of beef cattle and ICLS was carried out. In the second, an economic and risk analysis of the three production systems. Because of the first stage, the main risk factors in beef cattle farming were climatic conditions, production cost, investment capacity and farm management. In the ICLS there were changes such as soybean yield (Glycine max) and lack of knowledge of the activity. However, of the total risks considered most important, half of them were present in both activities. In the second stage, three production systems were established, cycle complete beef cattle (SBC), cycle compete beef cattle associated with leasing of a soybean area (SLS) and cycle compete beef cattle with the cultivation of soybean by the owner (SCS). The system with the highest gross margin was SLS (R$ 223.57/ha) compared to the other two systems (SBC: R$ 138.11/ha; SCS: R$ 149.62/ha). The SCS presented the highest risk among the systems, due to the greater range of gross margins. The average productivity of livestock was similar in the SBC and SLS systems (129.55 and 131.74 kg PV/ha/year). Except for soybean yield that were the main risk at SCS, all others were linked to market risk sources. It is concluded that farmers perceive the SIPA with greater risk than beef cattle systems. In both cases, production risks are the one that presents the highest number of factors with high risk of occurrence and, therefore, should receive special attention. This was consolidated when we concluded that SLS presented a better gross margin and a lower risk than the SBC, and the latter was the one that presented the highest risk. However, the risks that most influenced the gross margin variation were the market, not the production.

O objetivo do trabalho foi realizar uma análise econômica e de risco em sistemas integrados de produção agropecuária (SIPA) e de bovinos de corte de ciclo completo na Campanha Meridional do Rio Grande do Sul, região sul do Brasil, por um modelo de simulação. O modelo foi desenvolvido e operado em planilhas dinâmicas do Microsoft Excel®. O trabalho foi dividido em duas etapas, na primeira, foi realizada uma identificação e análise dos riscos existentes na produção de bovinos de corte e SIPA. Na segunda, foi realizada uma análise econômica e uma avaliação dos riscos de três sistemas de produção. Como resultado da primeira etapa, os principais fatores de risco na bovinocultura foram, condições climáticas, custo de produção, capacidade de investimento e gestão da propriedade. Na SIPA foram identificados novos ricos, como a produtividade da soja (Glycine max) e desconhecimento da atividade. No entanto, do total dos riscos considerados mais importantes, metade deles estão presentes nas duas atividades. Na segunda etapa, foram estabelecidos três sistemas de produção, bovinocultura de corte de ciclo completo (SBC), bovinocultura de corte de ciclo completo associado com leasing de uma área para soja (SLS) e bovinocultura de corte de ciclo completo com o cultivo de soja pelo próprio pecuarista (SCS). O sistema que apresentou maior margem bruta foi o SLS (R$ 223,57/ha) comparado aos outros dois sistemas (SBC: R$ 138,11/ha; SCS: R$ 149,62/ha). O SCS apresentou o maior risco entre os sistemas, devido a maior amplitude de resultados na margem bruta. A produtividade média da pecuária foi similar nos sistemas SBC e SLS (129,55 e 131,74 kg PV/ha/ano). Com exceção da produtividade da soja que foi o principal risco no SBS, todos os outros estiveram ligados as fontes de risco de mercado. Conclui-se que os produtores rurais percebem o SIPA com maior risco do que a bovinocultura. Em ambos os casos, o risco de produção é o que apresenta o maior número de fatores com alto risco de ocorrência e, portanto, deve receber especial atenção pelos produtores rurais. O que foi consolidado quando se concluiu que o melhor sistema foi o SLS por apresentar melhor margem bruta e menor risco que o SCS, e este último foi o que apresentou o maior risco, no entanto, os riscos que mais influenciaram a variação da margem bruta foram os de mercado e não os de produção. / The aim of this study was compare the economic and risk analysis on an integrated crop-livestock (ICLS) and a cycle complete beef cattle systems in the Campanha Meridional of Rio Grande do Sul, Brazilian Southern Region, through a simulation model. The simulation model was developed and operated through Microsoft Excel® dynamic worksheets. The research was divided in two stages, in the first, an identification and analysis of the existing risks in the production of beef cattle and ICLS was carried out. In the second, an economic and risk analysis of the three production systems. Because of the first stage, the main risk factors in beef cattle farming were climatic conditions, production cost, investment capacity and farm management. In the ICLS there were changes such as soybean yield (Glycine max) and lack of knowledge of the activity. However, of the total risks considered most important, half of them were present in both activities. In the second stage, three production systems were established, cycle complete beef cattle (SBC), cycle compete beef cattle associated with leasing of a soybean area (SLS) and cycle compete beef cattle with the cultivation of soybean by the owner (SCS). The system with the highest gross margin was SLS (R$ 223.57/ha) compared to the other two systems (SBC: R$ 138.11/ha; SCS: R$ 149.62/ha). The SCS presented the highest risk among the systems, due to the greater range of gross margins. The average productivity of livestock was similar in the SBC and SLS systems (129.55 and 131.74 kg PV/ha/year). Except for soybean yield that were the main risk at SCS, all others were linked to market risk sources. It is concluded that farmers perceive the SIPA with greater risk than beef cattle systems. In both cases, production risks are the one that presents the highest number of factors with high risk of occurrence and, therefore, should receive special attention. This was consolidated when we concluded that SLS presented a better gross margin and a lower risk than the SBC, and the latter was the one that presented the highest risk. However, the risks that most influenced the gross margin variation were the market, not the production.

The aim of the thesis is to compare two systems of cost calculation - the calculation of total costs and the calculation of variable costs - on the farm Těšovský statek, s.r.o. The calculation are compiled for various sections of the plant and animal production.

O estudo consistiu de dois experimentos com o objetivo de avaliar o efeito metabólico, custos e viabilidade econômica de dietas com diferentes fontes nitrogenadas e teores proteicos. No primeiro experimento avaliou-se o efeito de dois teores de proteína bruta (PB) (130 e 148g/kg de MS) e duas fontes nitrogenadas (farelo de algodão 38 e grão de soja cru integral) na dieta de vacas leiteiras com cana de açúcar como volumoso, sobre as frações nitrogenadas do leite, balanço de nitrogênio e perfil metabólico. Foram utilizadas 12 vacas da raça Holandesa com 155 (±65) dias em lactação, agrupadas em três quadrados latinos 4x4 contemporâneos, com período experimental de 21 dias, sendo 14 dias para adaptação às dietas e os sete últimos para a realização das coletas. As vacas foram alojadas em baias individuais e alimentadas ad libitum. As amostras de leite para análise do balanço nitrogenado e frações nitrogenadas foram coletadas no 15° dia de cada período. O consumo e balanço de nitrogênio foram maiores para vacas alimentadas com dietas com 148 g PB/kg de MS. Por outro lado, vacas alimentadas com dietas contendo farelo de algodão apresentaram maior excreção de nitrogênio no leite do que vacas alimentadas com grão de soja cru integral. A relação entre caseína e proteína verdadeira no leite foi maior em vacas alimentadas com grão de soja cru integral. Houve interação entre fonte nitrogenada e teor de PB da dieta sobre as concentrações de nitrogênio ureico no leite (NUL) e nitrogênio não proteico (NNP). A concentração de NUL foi maior em vacas alimentadas com farelo de algodão e com maior teor de PB, em contrapartida houve menor excreção de NUL em vacas alimentadas com grão de soja com maior teor proteico. Não houve efeito das dietas sobre os teores de proteína do leite, nitrogênio não caseinoso (NNC), caseína e proteína do soro. Conclui-se que o uso de dietas com 130g de PB/Kg na MS não altera o balanço de nitrogênio e de composição do leite de vacas leiteiras em comparação com teores de 148g/Kg de PB na MS, e resultam em menor excreção de nitrogênio no ambiente. No segundo experimento foram calculados os custos e margens totais de dietas com cinco fontes nitrogenadas principais (ureia, farelo de soja, farelo de algodão, grão de soja cru integral e farelo de glúten de milho) e cinco teores proteicos (130, 145, 148, 157 e 160 g/kg de MS) com cana de açúcar como volumoso para vacas em lactação. Os dados foram provenientes de três estudos conduzidos com a finalidade de coleta de dados produtivos e respostas metabólicas. A análise econômica foi realizada com base nos preços históricos deflacionados (corrigidos do efeito da inflação) praticados durante o período 2002 a 2012, e no cálculo dos custos de alimentação, em função do consumo de alimento, da produção de leite e do teor de proteína bruta no leite. Dietas com cana de açúcar com teor proteico de 14,5% com ureia como fonte nitrogenada principal apresentaram a maior margem bruta (diferença entre a receita da venda do leite e do custo da dieta) com valor médio anual de R$1,85.vaca-1.dia-1. A dieta com 14,8% de PB com grão de soja cru integral apresentou a menor margem bruta de R$ 2,16.vaca-1.dia-1. / The study consisted of two experiments to evaluate the N balance and economical analysis of diets with different nitrogen sources and crude protein levels. On the first experiment it was evaluated the effect of two crude protein (CP) levels (130 e 148 g/kg DM) and two nitrogen sources (cottonseed meal 38% and whole raw soybean) in diets of dairy cows using sugar cane as forage on nitrogen in milk, nitrogen balance and metabolic parameters. Twelve Holstein cows with 155 (±65) days in lactation were distributed into three contemporary 4x4 Latin squares, with experimental period of 21 days, 14 days for diet adaptation and the remaining seven days for sampling. The cows were housed in individual pens and fed ad libitum. Milk samples for nitrogen balance and milk nitrogen fractions analysis were collected on the 15th day of each experimental period. Nitrogen intake and nitrogen balance were higher for the cows fed diets with 148 g CP/kg DM. However cows fed diets with cottonseed meal had higher nitrogen excretion in milk than cows fed diets with whole raw soybean. The casein: true milk protein ratio was higher in cows fed diets with whole raw soybean. There was interaction between the nitrogen source and the diet CP content on the milk urea nitrogen and non-protein nitrogen. Milk urea nitrogen was higher in cows fed diets with cottonseed meal and higher CP concentrations, however lower milk urea nitrogen was observed in cows fed diets with whole raw soybean and higher CP concentration. The concentration of crude protein, noncasein protein, casein and whey protein in milk did not differ between diets. In conclusion the use of low concentrations of protein (130g/Kg in MS) does not affect the performance of dairy cows and provides lower excretion of nitrogen in the environment. On the second experiment, the costs and the gross margin were calculated for diets formulated with five nitrogen sources (urea, soybean meal, cottonseed meal, whole raw soybean and corn gluten meal) and five protein levels (130, 145, 148, 157 e 160 g/kg DM) using sugar cane as forage. Performance data were obtained from three experiments conducted previously. Economical analysis were performed based on historical prices adjusted for the effect of inflation during the period between 2002 and 2012 and based on the feed costs, cow intake, milk prodution and milk protein levels. The higher gross margin (difference between the income from milk sale and diet costs) were obtained for 145 g/kg of CP in DM diets and urea as main nitrogen source, with mean of R$1,85.vaca-1.dia-1. The lower gross margin were observed in the 148 g/kg of CP in DM diet and whole raw soybean as nitrogen source, with mean of R$ 2,16.vaca-1.dia-1.

The experiment was carried out with the objective of evaluating the gross margin, the productive and reproductive performance of beef heifers kept exclusively on ryegrass pasture (Lolium multiflorum Lam.) or ryegrass receiving 0.5 and 1.0% of body weight (BW) of whole rice bran as supplement, provided daily at at 2:00 p.m. The grazing method was the rotational and the interval between grazings was set by the thermal sum required for the appearing of 1.5 ryegrass leaf (187.5º C). The experimental design was completely randomized with repeated measures, three feeding systems and two and two area replications. Heifers in different feeding systems were kept in similar forage mass and canopy height when they came out of plots in all paddocks. The heifers average daily gain did not differ between the feeding systems. The stocking rate and weight gain per area were higher when heifers received 1.0% BW of whole rice bran. The provision of 0.5% BW of WRB allowed stocking rate and capacity gain for intermediate area between the other feeding systems. The higher gross margin was observed when heifers received 0.5% BW. The variable cost obtained for the different feeding systems showed increasing behavior depending on the WRB levels, surpassing the exclusive use of ryegrass in 37.2% and 60.6%. The final body weight, body condition score and reproductive tract score did not differ between the feeding systems. Considering an adult animal with an average body weight of 450 kg, the heifers at the beginning of the experiment showed 34% of mature body weight and final average body weight of 56% of adult weight. / O experimento foi conduzido com o objetivo de avaliar a margem bruta, o desempenho produtivo e reprodutivo de bezerras de corte mantidas exclusivamente em pastagem de azevém (Lolium multiflorum Lam.) ou em azevém recebendo 0,5 e 1,0% do peso corporal (PC) de farelo de arroz integral (FAI) como suplemento, fornecido diariamente às 14 horas. O método de pastejo foi o rotativo e o intervalo entre pastejos foi estabelecido considerando a soma térmica necessária para a emissão de 1,5 folha de azevém (187,5º C). O delineamento experimental foi o inteiramente casualizado, com medidas repetidas no tempo, três sistemas alimentares e duas repetições de área. As bezerras, nos diferentes sistemas alimentares, foram mantidas em similar massa de foragem e altura de dossel quando saíram das parcelas em todos os piquetes. O ganho médio diário das bezerras não diferiu entre os sistemas alimentares. A taxa de lotação e o ganho de peso por área foram maiores quando as bezerras receberam 1,0% do PC de farelo de arroz integral. O fornecimento de 0,5% do PC de FAI permitiu taxa de lotação e ganho por área intermediários entre os demais sistemas alimentares. A maior margem bruta foi observada quando as bezerras receberam 0,5% de FAI. O custo variável obtido para os diferentes sistemas alimentares apresentou comportamento crescente em função dos níveis de FAI, superando o uso exclusivo do azevém em 37,2% e 60,6%. O peso corporal final, o escore de condição corporal e o escore do trato reprodutivo não diferiram entre os sistemas alimentares. Considerando um animal adulto com peso corporal médio de 450 kg, as bezerras ao início do experimento apresentaram 34% do peso corporal adulto e peso corporal final médio de 56% do peso adulto.

Thesis (Ph.D. (Agricultural Economics )) -- University of Limpopo, 2021 / Regardless of the strategies adopted globally and nationwide to fight food insecurity within communities, particularly in the rural context, poverty becomes a major constituent which translates to most rural households experiencing food insecurity shocks. Given the high unemployment rate in South Africa which triggers several household’s vulnerability to food insecurity, the country has diverse natural resources which include indigenous plants such as Indigenous Leafy Vegetables (ILVs), which can be used as food and for business purposes by its residents. Irrespective of the diversity of ILVs in South Africa, there is a significant decline in the production and consumption of ILVs particularly in rural areas where these vegetables are mostly available. In addition, production and consumption of ILVs may not only address food insecurity but these vegetables may benefit households through the income obtained from their sales. The income generated from sales of ILVs may therefore assist towards improving and sustaining rural livelihood needs. Given this background information, the study aimed at assessing ILV production for income generation and food security among rural households in the Eastern Cape Province (ECP) of South Africa. The study was conducted within the three district municipalities of the ECP which were selected because statistics report these districts to be the most affected areas by poverty within the province. These districts are OR Tambo District Municipality (ORTDM), Alfred Nzo District Municipality (ANDM) and Joe Gqabi District Municipality (JGDM). Multistage and proportional random sampling procedures were employed to select households which could participate in the study. Thus, 407 households within these three (3) districts municipalities were used for the purposes of the study. The study also included interviewing role players within the ILV production value chain, thus a snowball sampling procedure was used to select role players. Sixteen hawkers and three input suppliers were interviewed from the three district municipalities. In addition, from the 407 households that were interviewed, 260 households from the three district municipalities reported to be producers of ILVs. A structured questionnaire was therefore used to collect pertaining data allied in achieving the aim of the study. The collected data was captured using Excel 2016, after data cleaning, it was then exported to Statistical Package for Social Sciences (SPSS) version 25 for analysis. Numerous analytical models were used from SPSS 25. For instance, to identify and describe socio-economic characteristics of households, to assess the most produced ILVs from the study areas and to identify role players within the ILV production value chain, descriptive statistics in a form of means, percentages, frequencies, and standard deviation was used. To determine factors which influence production of ILVs, a Binary Logistic Regression Model was used. A Multinomial Logistic Regression model was used to determine factors which influence different uses of ILVs by households and to determine factors influencing food security status among households. A gross margin analysis was used to estimate viability from each ILV produced, harvested and sold, while Household Food Insecurity Access Scale (HFIAS) was used to measure food security status among households. Lastly, a correlation matrix was also used to determine the relationship between the role players and their functions among the ILV production value chain. Based on the results, the study therefore concluded that, from the three district municipalities used in the study, there are various ILVs growing naturally and produced. The production of ILVs from these municipalities is habituated by socio economic characteristics of households, wherein households use ILVs for various purposes which include these vegetables as source of food, medicine and livestock feed. The use of ILVs among households is influenced by socio-economic characteristics and seasonal availability of ILVs in ORTDM, while in ANDM and JGDM, the use of ILVs by households is conditioned by socio-economic characteristics of households, knowledge/ awareness related to nutrition and health benefits of ILVs and seasonal production of ILVs. Furthermore, this research concludes that, ILVs have a potential of diversifying diets and addressing food insecurity problems within rural parts of the three districts. Given the positive gross margins from the three districts, production and selling of ILVs has a potential to contribute to rural household income. Lastly, the study concludes that, the ILV production value chain system lacks governmental support in the form of institutional engagement since there is no evidence of extension officer support from these three district municipalities concerning ILVs production. To this end, the study recommends that, policy makers should further establish inclusion of ILVs in both farming and food systems. Also, government and related institutions which focus on sustainable rural development must intervene in promoting production of ILVs particularly within rural contexts since production of these vegetables may alleviate poverty through job creation, addressing food insecurity and income generation. Thus, a successful intervention of government and policy makers in ILV production would have a potential of translating to sustainable rural livelihoods / National Research Foundation (NRF)

Les exploitations mixtes d'agriculture-élevage sont le pilier des systèmes agricoles des pays en développement. Dans les hauts plateaux de Madagascar, les exploitations familiales d'agriculture-élevage sont basées sur l'association riz et élevage bovin. Les bovins ont un rôle central dans l'économie et la reconnaissance sociale de ces exploitations malgaches. Cependant ces exploitations sont souvent confrontées à des problèmes de faibles productivités liés à la dégradation de la fertilité des sols et à un accès limité aux intrants. Dans ce contexte, les exploitants doivent gérer les ressources végétales pour trouver un compromis entre alimentation humaine, alimentation animale et retours aux sols. Certaines pratiques de gestion des biomasses peuvent aggraver les phénomènes de dégradation de la fertilité des sols et remettre alors en cause la durabilité des exploitations. L'objectif de cette thèse est de montrer que la diversité des pratiques de gestion des biomasses au sein des exploitations familiales d'agriculture-élevage des hauts plateaux de Madagascar conditionne la durabilité des systèmes en termes de fertilité des sols, de recyclage des éléments nutritifs, de revenus et de sécurité alimentaire. Pour cela, il a été nécessaire de : i) caractériser au préalable la diversité des exploitations familiales d'agriculture-élevage du Vakinankaratra et de comprendre le fonctionnement de ces exploitations mixtes ; ii) étudier les effets des pratiques de gestion des parcelles sur la variabilité de la fertilité des sols des exploitations ; iii) évaluer la durabilité des exploitations d'agriculture-élevage et tester l'impact d'améliorations des pratiques d'alimentation animale, de gestion des effluents et de fertilisation sur la durabilité des exploitation. Quatre exploitations d'agriculture-élevage du Vakinankaratra, sélectionnées à dires d'experts, ont été enquêtées par immersion. Une étude typologique des exploitations d'agriculture-élevage du Vakinankaratra a été effectuée. Des prélèvements de sol ont été effectués pour l'ensemble des parcelles des quatre exploitations d'agriculture-élevage étudiées. Un outil de calcul des flux d'azote au sein des exploitations a été élaboré, puis a été associé aux matrices du Network Analysis afin de générer des indicateurs environnementaux, sociaux et économiques. Cet outil a été utilisé pour simuler les options d'améliorations des pratiques d'alimentation animale, de gestion des effluents et de fertilisation.L'étude typologique a identifié six types d'exploitations d'agriculture-élevage au Vakinankaratra. L'étude du fonctionnement des exploitations sélectionnées a mis en évidence d'une grande diversité des pratiques d'alimentation des animaux, de gestion des effluents d'élevage et de fertilisation. Une hétérogénéité de la fertilité des sols induite par les pratiques de gestion des parcelles a été révélée. Pour les quatre exploitations étudiées, l'amélioration des pratiques d'alimentation du troupeau bovin laitier associée à l'amélioration des pratiques de gestion des effluents d'élevage a permis d'améliorer la durabilité environnementale (efficience azotée globale, recyclage de l'azote, bilan azoté du sol), économique (marge brute agricole) et sociale (autosuffisance alimentaire).Ce travail a permis de caractériser la diversité des exploitations d'agriculture-élevage du Vakinankaratra, la diversité des pratiques et leurs effets sur la fertilité du/des sol. Cette étude s'est avérée être une approche intéressante pour évaluer des options d'amélioration de la durabilité des exploitations d'agriculture-élevage dans un contexte peu documenté. / Mixed crop-livestock systems constitute the backbone of agriculture in developing countries. In highlands of Madagascar, crop–livestock systems are based on rice and cattle. Cattle play a major role in the economy and the social recognition of these smallholder farms. Smallholder farms used to face with low crop productivity related to soil fertility degradation and to low access to inputs. In this context, smallholders have to manage plant resources in order to find a trade-off between food, feed and soil returns. Some biomass management may increase soil fertility degradation and then compromise farms sustainability.The objective of this thesis is to show that the diversity of biomass management on smallholder crop–livestock systems of highlands of Madagascar determines the sustainability of farming systems in terms of soil fertility, nutrients recycling, incomes and food security. For this, it was necessary to: i) characterize the diversity of crop-livestock systems in the region of Vakinankaratra and understand how smallholder farms are managed; ii) study the effects of soil management on the soil variability; iii) assess the farms sustainability and explore improvements of feeding, manure management and fertilization.Four crop-livestock farms of the Vakinankaratra (selected with local experts) were surveyed using participant observation methodology. A typology of crop-livestock farms was performed. Topsoil samples were collected in all plots of the four cases studies. A nitrogen flows calculating tool was developed and has been associated with Network Analysis matrices to generate environmental, social and economic indicators. This tool was used to simulate improvements in feeding, manure management and fertilization.The typology identified six farm types of crop-livestock systems in the Vakinankaratra. The farms study revealed a great diversity of animal feeding practices, manure management and fertilization. Heterogeneity of soil fertility induced by farmer management was shown. For the four case studies, improved feeding practices on dairy combined with improved manure management have increased environmental (farm nitrogen efficiency, nitrogen recycling, soil nitrogen balance), economic (agricultural gross margin) and social (food self-sufficiency) sustainability.This study characterized the diversity of crop-livestock farms of the Vakinankaratra, the diversity of practices and their effects on soil fertility. It proved to be an interesting approach to explore options for improving sustainability of crop-livestock farms in context of data scarcity.

Lentil (Lens culinaris Med.) is an important component of the human diet in the world, but in the meantime, Europe produces only 26% of the lentils it consumes. This is partly due to strong agronomic weaknesses that reduce yield such as lodging, bruchid beetles and weeds, especially in organic farming. Intercropping, the simultaneous growing of two or more species in the same field is tested here as an option to reduce these drawbacks and develop organic lentil production. The aims of this thesis were to (1) assess the potential of lentil-spring wheat intercrops to produce organic lentil, (2) understand the mechanisms that explain their performances, and (3) evaluate the profitability of such intercrops. A two-year field experiment was carried out in southwestern France in 2015 and 2016 under organic farming rules. Four lentil and two wheat cultivars were grown as sole crops and intercrops in multiple additive and substitutive designs. Our results showed that the total intercrop attainable grain yield was higher than the mean of sole crops. Yet, lentil yield in intercrop was lower than in sole crop as the result of a strong competition for resources from wheat in early lentil growth stages reducing the number of branches per plant of lentil. This led to lower gross margins of intercrops. However, lentil lodging was strongly reduced in intercrops thus its mechanical harvest efficiency increased. This led to similar mechanically harvested yields of lentil in intercrop and sole crop. Consequently, after mechanical harvest and grain cleaning, the marketable gross margin of intercrops was higher than that of sole crops. Our results suggest that (1) intercrop had no effect on bruchids, (2) the most effective intercrop is when lentil is at sole crop density and wheat at 15-20%, (3) intercrop performance is due to complementary use of N pools through legume N2 fixation and (4) the intensity of interspecific interactions depends on year, wheat density and genotypes. Our work indicates that lentil-spring wheat intercrop can develop organic lentil production but a better understanding of Genotype x Environment x Cropping system interactions may be useful to design optimized managements.

The aim of this thesis is to evaluate management control system in a company and pro-pose measures for better use of management control system as a subsystem of manage-ment of the company supporting the achievement of business objectives of the owners in the changing market environment. Thesis consists three main parts. The first theoretical part contains information about management control system. Analysis of the current state of management control system describes state of the management control system in a company and in the last section are suggestions for possible improvements of man-agement control system.

MSCAGR (Agricultural Economics) / Department of Agricultural Economics / This research aimed to assess the profitability of sweet potato production enterprises. The focus areas were on: determining differences in profitability of different sweet potato enterprises located in different villages; identifying factors that affect the profitability of sweet potato enterprises; determining differences in the sweet potato markets; and identifying marketing channels utilised by sweet potato enterprises. The study was carried out in 8 villages in Makhado and Thulamela local municipalities of the Vhembe district of Limpopo province. There were 78 sweet potato farmers identified and interviewed as respondents in the study. A gross margin analysis model was used to calculate the profitability of sweet potato enterprises, while a multiple regression model was adopted to analyse factors that affect profitability of sweet potato enterprises. The study revealed the domination of females in sweet potato production, wherein 69.2% of the respondents were females. Furthermore, the study revealed that 16.7% of the respondents were illiterate, 24% of the respondents had never received any form of agricultural training. The findings of the study revealed that sweet potato production is a viable and profitable enterprise in the study area. Farmers recorded an average gross margin of R11 329.94 per ha. Furthermore, labour cost and fertilizer cost accounted for the highest costs incurred in production contributing 45% and 32% respectively to total costs. The results of the study further revealed that six variables were statistically significant to profitability. Occupation status, farming experience, unpaid family members, and labour cost were statistically significant to profitability at the 1% level of significance; whereas tractor hire cost and chemical cost were statistically significant to profitability at the 5% level of significance. The study recommends that stakeholders involved in agriculture and community development should attend to issues such agro-processing trainings and extension services offered to the farmers in the Vhembe district.