Made available in DSpace on 2016-01-26T18:56:25Z (GMT). No. of bitstreams: 1 DISSERTACAO_AGRONOMIA_Oscar_mar07_novo1.pdf: 270672 bytes, checksum: 7eba03f64317fd976224aae8616283fc (MD5) Previous issue date: 2006-01-31 / The cassava (Manihot esculenta Crantz) is currently of great economic and social importance for Brazil. Important factors for evaluation of cassava cultivars under field conditions are: productivity (mg ha-1); Dry Matter Percentage (MS%). In order to carry out nutritional evaluation the following parameters must be considered: Fat - Ethereal Extract (EE%); Ash (%); Gross Digective Fiber (FB%); Gross Protein (PB%); Non Nitrogenate Extrative (ENN%) and Total Digestive Nutrient (NDT). The aim of this study was to verify differences between 16 cassava cultivars cultivates whit differents spacements: 0,60 m and 0,80 m whithin the line and 0,90 m between lines. The experimental design performed in random blocks with some treatments in common, with four repetitions. The results showed that the cultivars Espeto; Eucalipto e IAC 144-86 obtained smaller productivities. The cultivars Iracema; IAC 184-89; Fibra; IAC 89-87; Fécula Branca; IAC 32-88; IAC 14; Olho Junto; Mico; IAC 12; IAC 169-86; IAC 5-88; IAC 15 showed the highest yields. The bromatological characteristics didn't present statistical differences. The among cultivars 0,60m in the spacement increased the productivity in 12% when compared to the 0,80m spacement. / A mandioca (Manihot Esculenta Crantz) é atualmente de grande importância econômica e social para o Brasil. Fatores importantes para avaliação de cultivares de mandioca a campo são: produtividade (Mg ha-1) e o teor de Matéria Seca (MS%). Para avaliação nutricional deve-se atentar para: Gordura Extrato Etéreo (EE%); Cinza (%); Fibra Bruta (FB%); Proteína Bruta (PB%); Extrativo Não Nitrogenado (ENN%) e Nutrientes Digestivo Totais (NDT%). O presente trabalho objetivou estudar as diferenças entre cultivares de mandioca, com espaçamentos de 0,60m e 0,80m na linha e 0,90m na entre linhas. O delineamento experimental utilizado foi análise conjunta de experimentos em blocos ao acaso com alguns tratamentos em comuns, com quatro repetições. Conclui-se, no presente ensaio que as cultivares Espeto; Eucalipto e IAC 144-86, obtiveram menores produtividades estatisticamente; As cultivares Iracema; IAC 184-89; Fibra; IAC 89-87; Fécula Branca; IAC 32-88; IAC 14; Olho Junto; Mico; IAC 12; IAC 169-86; IAC 5-88; IAC 15 obtiveram as melhores produtividades estatisticamente; As características bromatológicas não apresentaram diferenças estatísticas; O espaçamento de 0,60m aumentou a produtividade em 12% quando comparado ao espaçamento de 0,80m

Made available in DSpace on 2016-07-18T17:51:09Z (GMT). No. of bitstreams: 1 DISSERTACAO_AGRONOMIA_Oscar_mar07_novo1.pdf: 270672 bytes, checksum: 7eba03f64317fd976224aae8616283fc (MD5) Previous issue date: 2006-01-31 / The cassava (Manihot esculenta Crantz) is currently of great economic and social importance for Brazil. Important factors for evaluation of cassava cultivars under field conditions are: productivity (mg ha-1); Dry Matter Percentage (MS%). In order to carry out nutritional evaluation the following parameters must be considered: Fat - Ethereal Extract (EE%); Ash (%); Gross Digective Fiber (FB%); Gross Protein (PB%); Non Nitrogenate Extrative (ENN%) and Total Digestive Nutrient (NDT). The aim of this study was to verify differences between 16 cassava cultivars cultivates whit differents spacements: 0,60 m and 0,80 m whithin the line and 0,90 m between lines. The experimental design performed in random blocks with some treatments in common, with four repetitions. The results showed that the cultivars Espeto; Eucalipto e IAC 144-86 obtained smaller productivities. The cultivars Iracema; IAC 184-89; Fibra; IAC 89-87; Fécula Branca; IAC 32-88; IAC 14; Olho Junto; Mico; IAC 12; IAC 169-86; IAC 5-88; IAC 15 showed the highest yields. The bromatological characteristics didn't present statistical differences. The among cultivars 0,60m in the spacement increased the productivity in 12% when compared to the 0,80m spacement. / A mandioca (Manihot Esculenta Crantz) é atualmente de grande importância econômica e social para o Brasil. Fatores importantes para avaliação de cultivares de mandioca a campo são: produtividade (Mg ha-1) e o teor de Matéria Seca (MS%). Para avaliação nutricional deve-se atentar para: Gordura Extrato Etéreo (EE%); Cinza (%); Fibra Bruta (FB%); Proteína Bruta (PB%); Extrativo Não Nitrogenado (ENN%) e Nutrientes Digestivo Totais (NDT%). O presente trabalho objetivou estudar as diferenças entre cultivares de mandioca, com espaçamentos de 0,60m e 0,80m na linha e 0,90m na entre linhas. O delineamento experimental utilizado foi análise conjunta de experimentos em blocos ao acaso com alguns tratamentos em comuns, com quatro repetições. Conclui-se, no presente ensaio que as cultivares Espeto; Eucalipto e IAC 144-86, obtiveram menores produtividades estatisticamente; As cultivares Iracema; IAC 184-89; Fibra; IAC 89-87; Fécula Branca; IAC 32-88; IAC 14; Olho Junto; Mico; IAC 12; IAC 169-86; IAC 5-88; IAC 15 obtiveram as melhores produtividades estatisticamente; As características bromatológicas não apresentaram diferenças estatísticas; O espaçamento de 0,60m aumentou a produtividade em 12% quando comparado ao espaçamento de 0,80m

Ethno-archaeological evidence shows that taro [Colocasia esculenta (L.) Schott] originated in Asia. It may have been brought into South Africa a few hundred years after 300 BC from Madagascar, where Malaysian settlers introduced it about 300 BC. The crop is grown in the tropical and subtropical regions of the world, largely for subsistence on farms. In South Africa, taro is mainly produced in the subtropical coastal belt, stretching from Bizana in the Eastern Cape to the KwaZulu-Natal north coast. Although it is a staple crop for the subsistence farmers who grow it, there are no data on taro agronomy in South Africa. The hypothesis of this study was that traditional knowledge about taro production practices is not adequate to form a basis for agronomic and extension interventions to promote the status of the crop to that of a commercial commodity. A survey was conducted at two districts in KwaZulu-Natal, Umbumbulu and Ndwedwe, where taro is a staple crop. The objective of the survey was to determine the cultural practices associated with taro production, including knowledge about varieties, agronomy, plant protection, storage and marketing. Qualitative data obtained from the survey was used to plan an investigation into the agronomy of taro. The survey showed that subsistence farmers at Ndwedwe and Umbumbulu used traditional methods for taro production that had very small influence from the extension services from the Department of Agriculture. The farmers identified three varieties of taro, which they designated as the "red", "white" and "Zulu" types. The "red" and "white" designations were based on consistent crop morphological characteristics. This finding confirmed the reliability of indigenous knowledge for crop classification.The survey also revealed that wetland and dryland conditions are used to produce taro. At Umbumbulu, production occurred predominantly under dryland conditions, whereas at Ndwedwe there was an almost even utilisation of both wetlands and drylands. At both locations, the farmers estimated plant spacing using their feet, which showed that the plant populations would be about 18400 plants ha(-1). Full corms were a predominant type of propagation material. In the light of the survey findings about site types (wetland or dryland), propagation material and plant spacing for taro production, field experiments were designed to 1) determine the effect of site type on taro production, 2) compare three propagule types (full corm, full corm with a shoot and half corm) in taro production and 3) examine the effect of planting density (18400, 24600 and 37000 plants ha(-1) on the performance of propagules with respect to production under wetland and dryland conditions. Field experiments showed that wetland cultivation improved taro yield by 40% compared with dryland production. However, in each of the two site categories, there were significant differences between sites. Using full corms with shoots also enhanced taro yield (42% > full corms without shoots and 66% > half corms), when means were determined across all sites and planting densities. Increasing planting density also caused an increase in taro production (4.9 t ha (-1), 6.8 t ha (-1) and 11.5 t ha (-1), for 18400,24600 and 37000 plants ha,(-1), respectively; LSD (0.05) = 1.4 t ha,1). The enhanced performance of taro under wetland conditions, where corms with a shoot were used and at high planting densities may have been associated with photosynthetic efficiency. Wetland conditions and corms with shoots improved plant emergence and plant growth, which are essential agronomic conditions for efficient capture of the sun's energy for photosynthesis. It is proposed that using propagules with shoots and high plant populations under dryland conditions could enhance taro production. Although wetland cultivation enhanced yield, the survey showed that the total area of land that could be used for wetland cultivation at Ndwedwe and Umbumbulu was too small to warrant sustainable wetland production. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

The 48 members of the Ezemvelo Farmers' Organisation (EFO) in KwaZulu-Natal (KZN), South Africa (SA), that were fully-certified as organic farmers were surveyed during October-December 2004 to assess their perceived level of satisfaction, trust, cooperation and commitment in a formal supply chain producing amadhumbes (a traditional vegetable tuber), potatoes and sweet potatoes for a major SA supermarket group. Empirical recursive models show that a high level of satisfaction in the working relationship results in these farmers trusting the pack-house agent more. High levels of trust, in turn, lead to higher levels of both commitment to, and cooperation in, the supply chain. A simultaneous-equation model showed that EFO farmers with higher levels of commitment tend to be more cooperative, and that members with higher levels of cooperation tend to be more committed toward the working relationship. These results suggest that strategies to improve the working relationship with the pack-house agent need to promote satisfaction, trust, cooperation and commitment. For example, co-investment in better crop storage facilities at farm-level would promote satisfaction and hence trust. There is also scope for more cooperation in the planning of new organic crop products to grow and market, and to remove some price uncertainty by giving EFO farmers more information about prices that they will be paid by the pack-house agent in this supply chain. In addition, satisfaction and, hence, trust, cooperation and commitment may be improved by adopting a formal contract between the EFO farmers and the pack-house agent to replace the current, incomplete verbal contract that governs trading. Some issues that may be addressed in this contract are improved communication systems via regular meetings, renegotiations of trading terms so that farmers can benefit from positive changes in organic crop prices; guidelines for paying farmers more quickly by the pack-house agent; mechanisms to trace crop quality to a specific farmer to avoid free riding; and penalties for breaching the contractual arrangements. The 48 EFO farmers were also asked to give their perceptions of the main constraints on organic crop production and marketing in the formal organic crop supply chain. They perceived that uncertain climate, unavailability of tractor or draught power when needed, delays in payments for crops sent to the pack-house, lack of affordable inputs (particularly labour and manure), a lack of cash and credit to finance inputs, lack of affordable transport to market crops, more work than the family can handle, a lack of manure to purchase; and a lack of crop storage facilities and telephones to negotiate sales as the current top 10 constraints. Principal Component Analysis summarized the underlying dimensions in the 20 constraints ranked by these farmers as indicating "lack of market information and lack of market power"; "crop production expansion constraints"; "commitment to crop area expansion"; "lack of liquidity"; "lack of proper storage facilities"; and "lack of information about alternative markets". Potential solutions to better manage these perceived constraints include: improved risk management practices (e.g., supplemental irrigation, water-harvesting and small boreholes), improving access to tractor services via improved tractor scheduling or using local contractor services, quicker pack-house delivery payments, improving quality inspection at the departure points at EFO farm-level to reduce crop rejection rates and "free riding" by producers of lower quality organic crops, more interaction with the retailer to promote sales of organic crops, providing advice on how the EFO farmers can improve their bargaining power, and providing more information (e.g. crop prices) about other organic markets and changing consumer preferences. Apparently, the costs and benefits of these potential solutions, and how they will be financed, need to be evaluated. Real accounting marketing margins since 2001 showed that the farmer's share of the consumer's rand for the 48 fully certified organic EFO farmers rose, while their net returns (selling price less accounting costs) were lower than those of the pack-house agent and hawkers selling at the Isipingo market on the South Coast of KZN. Net returns for the 48 EFO farmers also seemed to be relatively higher if they sold through the informal supply chain (hawkers) rather than the formal supply chain. The EFO farmers' net returns may be improved by lowering operating costs and by aggressive marketing to customers willing and able to pay a price premium for organic crops. These farmers may also consider performing some of t he marketing services themselves (e.g. crop cleaning, grading and packaging) if they have the skills and can access more finance. There are, however, hidden benefits from maintaining the formal supply chain relationship, as the pack-house agent helped to secure tractor services and fencing, and facilitates access to the retailer. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.