Communities in the Sahel region are confronted with problems such as depletion of soil fertility, food insecurity, and climate change, which exacerbate poverty and malnutrition for the inhabitants. The farmlands in Toukar, Senegal, are rapidly denuded of native trees, mainly Acacia albida, that provide myriad benefits. Agroforestry systems, or the intentional use of trees in croplands, have become a potential vehicle to transform the capacities of subsistence farmers to achieve food security. The purpose of this study is to determine farmers' attitudes about agroforestry, who seems to practice it and support it, who is unsure about its values, and who seems opposed to it. I find that farmers who practice a more intact historic version of the Serer farming system are the most supportive of agroforestry and tend to be wealthier, while people who are seemingly more modern are less likely to adopt it and tend to be poorer.

Memoria para optar al título profesional de: Ingeniero Agrónomo / El objetivo de este estudio fue evaluar el efecto que genera un estrato arbóreo compuesto por Acacia caven (Mol.) Mol., en el rendimiento y desarrollo de un cultivo de trigo en la Estación Experimental Germán Greve Silva, Rinconada de Maipú, Región Metropolitana de Chile. Se establecieron cuatro parcelas de 64 m 2 , contando cada una de ellas con un espino adulto. Estas parcelas se sembraron en su totalidad con trigo cultivar Pandora INIA. Se analizaron tres tratamientos; SIE: sin influencia de espino; CIEBC: con influencia espino bajo copa; CIESE: con influencia espino al sur del espino. Se midieron las precipitaciones bajo y fuera de la copa de espino y la radiación fotosintéticamente activa incidente sobre el cultivo de trigo (PAR 0 ). En el suelo se midió: el contenido de agua, densidad aparente, capacidad de retención de agua a 33 y 1.500 kPa, pH, conductividad eléctrica, NPK disponible y contenido de materia orgánica. En el cultivo de trigo se midió: rendimiento de biomasa y de grano, componentes del rendimiento y el tiempo en alcanzar distintos estados fenológicos. Durante la temporada de crecimiento del cultivo, precipitaron 138,4 mm en los sectores de los tratamientos SIE y CIESE, mientras que en CIEBC, producto de la intercepción generada por las copas de los árboles, precipitaron aproximadamente 76,1 mm. El contenido de agua en el suelo fue mayor al momento de siembra en el tratamiento SIE, mientras que en madurez fisiológica el contenido de agua en el suelo fue mayor en el tratamiento CIEBC. Los niveles de PAR 0 fueron menores en el tratamiento CIEBC, representando en promedio un 45,8% del PAR 0 total recibido por el tratamiento SIE. La retención de agua entre 33 y 1.500 kPa fue mayor bajo el tratamiento CIEBC, siendo esta diferencia de un 2,28% superior, lo que implica un aumento del 25% en la capacidad de retención de agua aprovechable, respecto de los tratamiento SIE y CIESE. El tratamiento SIE presentó los mayores valores de biomasa aérea. El rendimiento de granos presentó diferencias estadísticamente significativas, siendo el tratamiento CIESE el que presentó los mayores rendimientos; mientras que los menores rendimientos se obtuvieron en el tratamiento CIEBC. Para las mediciones de estados fenológicos, se registraron diferencias en los días en alcanzar los estados de espigadura y madurez fisiológica. Para el estado fenológico de espigadura, se presentaron siete días de diferencia entre el tratamiento SIE y los tratamientos CIEBC y CIESE. Para el estado fenológico de madurez fisiológica esta diferencia aumentó a nueve días. Se concluye que el espino genera modificaciones microambientales y físico-químicas de suelo; sin embargo, estas modificaciones no provocaron un aumento en el rendimiento del cultivo de trigo.

Memoria para optar al Título Profesional de Ingeniero Agrónomo / La formación de Acacia caven se encuentra extendido entre el río Copiapó y el río Laja, utilizando cerca de 3.000.000 de hectáreas de secano. Entre los beneficios del matorral de Acacia caven se encuentran una mayor productividad de forraje bajo su influencia, aumento de materia orgánica bajo su copa, una mayor disponibilidad hídrica, protección para animales tanto del calor como del frío y el aprovechamiento de sus brotes y frutos como forraje en épocas de escasez. Estudios preliminares demostraron que la arquitectura o número de fustes del espino tiene un efecto sobre la producción de frutos; sin embargo, no se ha estudiado el efecto de la densidad poblacional y su interacción con la arquitectura. El propósito de esta investigación fue cuantificar el efecto de tres densidades poblacionales (distancia de 1-3 metros, 4-7 metros y mayor a 8 metros al individuo más cercano) y de tres arquitecturas de árboles (un fuste, dos a tres fustes y cuatro o más fustes) sobre la producción de frutos del espino., El estudio se realizó en un sector de 60 hectáreas que posee un espinal adulto, sin manejo silvícola. Se seleccionaron 180 árboles, combinando las densidades poblacionales y arquitecturas señaladas. Se cosechó la totalidad de los árboles al término del ciclo de floración y fructificación y se midió la producción de frutos, expresada en peso seco por individuo. Además, se midieron variables descriptivas de los árboles (altura total, altura de copa, ancho de copa norte-sur y este-oeste) para evaluar la relación entre estas variables y la producción de frutos, con el objetivo de construir ecuaciones predictivas. Se utilizó un diseño experimental completamente aleatorizado, con estructura factorial 3x3. El factor densidad contó con los niveles alta densidad, media densidad y baja densidad (AD, MD y BD respectivamente), mientras que el factor arquitectura contó con los niveles monofustal, dos a tres fustes y cuatro o más fustes (MF, 2F y 4F respectivamente). Se utilizaron 20 árboles por cada combinación de arquitectura y densidad. Numéricamente, los ejemplares en baja densidad y con arquitectura de 4F presentaron una mayor producción de frutos. No hubo diferencias significativas en la producción de frutos para los factores por separado, pero existió interacción significativa de la densidad en la arquitectura monofustal. El ancho de copa norte-sur fue la variable que mejor permitió estimar la producción de frutos, siendo más importante que los factores de densidad y arquitectura. Además, la densidad poblacional afecta el tamaño de copa de los árboles, disminuyendo en la medida en que la densidad aumenta. Se concluye que árboles con tamaño de copas similares poseen una producción de frutos similar y que la densidad poblacional influye sobre el tamaño de copa de los árboles, por lo que se considera que este factor es relevante para tomar medidas de manejo de espinales destinados a producción de frutos. / The Acacia caven scrub is wide spread between the Copiapó and Laja rivers, covering about 3 million rainfed hectares. Some of Acacia caven benefits are the greater forage under it influence, increased organic matter under it tree crown, greater water availability, protection for animals (both heat and cold) and the use of their buds and end fruits as fodder in times of shortage. Preliminary studies showed that the number of tree trunks of Acacia caven has an effect on fruit production, however the effect of population density and its interaction with the architecture has not being studied. The purpose of this research was to quantify the effect of three population densities (distance between 1 to 3, 4 to 7 and more than 8 meters to the closest individual) and of three tree architectures (one trunk, between 2 and 3, and 4 or more trunks) on Acacia caven fruit production. The research was made in an area of 60 hectares with adult trees, without silvicultural management. 180 trees where selected combining the indicated population densities and the architectures. All trees where harvested at the end of fructification cycle and the productions of trees where measured through dry weight of each individual. Also, descriptive variables of the trees where measured (total high, crown high, north to south crown diameter and east to west crown diameter) to evaluate the relation between these variables and fruit production, for constructing predictive equations. A 3 x 3 factorial experimental designed was used. The individuals were selected by random. The density factor was designed with 3 levels: AD, MD and BD, and the architecture factor was also designed with three levels: MF, 2F and 4F. Twenty trees for each combination of architecture and density were used. The individuals with low density and 4F architecture showed a major fruit production. No significant differences in the fruit production for each factors in its own where found, but a significant interaction of density on MF architecture was found. The north-south diameter was the descriptive variable that better allowed estimating the fruit production, being more important than density and architecture factors. Also, the population density has an effect on the crown diameter, diminishing by greater density. It concludes that trees with similar crown size have a similar fruit production and that the population density has an effect on the crown size. Therefore, it is considered that this factor (north-south diameter) is relevant for the management of Acacia caven for fruit production.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-16T15:20:26Z No. of bitstreams: 1 CamilaCostaDaNobrega_DISSERT.pdf: 2190053 bytes, checksum: 9e41824968362843bf6a2aeadef0cbce (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2017-01-16T15:27:09Z (GMT) No. of bitstreams: 1 CamilaCostaDaNobrega_DISSERT.pdf: 2190053 bytes, checksum: 9e41824968362843bf6a2aeadef0cbce (MD5) / Made available in DSpace on 2017-01-16T15:27:09Z (GMT). No. of bitstreams: 1 CamilaCostaDaNobrega_DISSERT.pdf: 2190053 bytes, checksum: 9e41824968362843bf6a2aeadef0cbce (MD5) Previous issue date: 2014-12-17 / Objetivou-se avaliar a produ??o, crescimento, distribui??o de biomassa e desrama artificial de tr?s esp?cies florestais Sabi? (Mimosa caesalpiniaefolia), Ac?cia (Acacia mangium) e Nim (Azadirachta indica), aos 12 e 24 meses de idade, em resposta ao m?todo de cultivo do solo. O delineamento experimental foi fatorial (2x3), correspondente a seis tratamentos distribu?dos em parcelas subdivididas em faixas com quatro blocos, sendo o fator principal dois m?todos de cultivo (intensivo - 1 e m?nimo - 0) e o fator secund?rio as esp?cies florestais (Sabi? - S, Ac?cia - A e Nim - N), com quatro repeti??es, perfazendo 24 parcelas. O plantio foi realizado no espa?amento 3x3 m, tendo 64 plantas/parcela. Nos tratamentos com cultivo intensivo utilizou-se esterco bovino (4,0 t/ha), superfosfato triplo - P2O5 (146,0 kg/ha) distribu?dos em sulcos e calc?rio (2,0 t/ha). Em todos os tratamentos aplicou-se NPK (6-30-6: 100 g/planta), em covetas laterais. O crescimento de cada ?rvore foi obtido com a medi??o da altura e do di?metro. Para a quantifica??o da biomassa desramada selecionou-se uma ?rvore da bordadura de cada parcela com altura e di?metro m?dios. Realizou-se a desrama at? a altura equivalente a 1/3 da altura da copa da ?rvore. Para o Sabi?, por ser uma esp?cie que apresenta maior n?mero de fustes foram deixados tr?s fustes mais vigorosos; enquanto, as esp?cies Ac?cia e Nim, apenas um fuste. Para a obten??o da biomassa da parte a?rea a ?rvore m?dia foi abatida, e seus componentes (folhas, galhos, casca e lenho) separados, pesados e secos, obtendo-se biomassa fresca e seca. N?o houve diferen?a significativa entre os tratamentos aos 12 meses para as vari?veis: altura, galho, casca e lenho. Aos 24 meses as vari?veis galho e casca n?o apresentaram diferen?a significativa. As vari?veis altura, DAP e lenho aos 24 meses apresentaram diferen?as estat?sticas superiores no cultivo intensivo para as tr?s esp?cies. As vari?veis biomassa seca total e folhas apresentaram diferen?as entre os m?todos de cultivo apenas para a esp?cie Nim. Para desrama artificial de folhas e total houve intera??o entre os fatores, em que a esp?cie e o tipo de cultivo influenciaram na quantidade desramada, havendo diferen?a significativa tamb?m entre as esp?cies e entre os tipos de cultivo, apenas o Sabi? n?o apresentou diferen?a entre os m?todos de cultivo. J? para galhos, houve diferen?a significativa entre as esp?cies e entre os tipos de cultivo, por?m n?o houve intera??o entre os fatores. Concluiu-se que o m?todo de cultivo do solo influencia na produ??o, crescimento, distribui??o de biomassa e quantidade de biomassa desramada artificialmente das esp?cies sabi?, ac?cia e nim de forma diferente. O m?todo de cultivo intensivo do solo influenciou positivamente a produ??o, crescimento e quantidade de biomassa desramada artificialmente das tr?s esp?cies. / Objetivou-se avaliar a produ??o, crescimento, distribui??o de biomassa e desrama artificial de tr?s esp?cies florestais Sabi? (Mimosa caesalpiniaefolia), Ac?cia (Acacia mangium) e Nim (Azadirachta indica), aos 12 e 24 meses de idade, em resposta ao m?todo de cultivo do solo. O delineamento experimental foi fatorial (2x3), correspondente a seis tratamentos distribu?dos em parcelas subdivididas em faixas com quatro blocos, sendo o fator principal dois m?todos de cultivo (intensivo - 1 e m?nimo - 0) e o fator secund?rio as esp?cies florestais (Sabi? - S, Ac?cia - A e Nim - N), com quatro repeti??es, perfazendo 24 parcelas. O plantio foi realizado no espa?amento 3x3 m, tendo 64 plantas/parcela. Nos tratamentos com cultivo intensivo utilizou-se esterco bovino (4,0 t/ha), superfosfato triplo - P2O5 (146,0 kg/ha) distribu?dos em sulcos e calc?rio (2,0 t/ha). Em todos os tratamentos aplicou-se NPK (6-30-6: 100 g/planta), em covetas laterais. O crescimento de cada ?rvore foi obtido com a medi??o da altura e do di?metro. Para a quantifica??o da biomassa desramada selecionou-se uma ?rvore da bordadura de cada parcela com altura e di?metro m?dios. Realizou-se a desrama at? a altura equivalente a 1/3 da altura da copa da ?rvore. Para o Sabi?, por ser uma esp?cie que apresenta maior n?mero de fustes foram deixados tr?s fustes mais vigorosos; enquanto, as esp?cies Ac?cia e Nim, apenas um fuste. Para a obten??o da biomassa da parte a?rea a ?rvore m?dia foi abatida, e seus componentes (folhas, galhos, casca e lenho) separados, pesados e secos, obtendo-se biomassa fresca e seca. N?o houve diferen?a significativa entre os tratamentos aos 12 meses para as vari?veis: altura, galho, casca e lenho. Aos 24 meses as vari?veis galho e casca n?o apresentaram diferen?a significativa. As vari?veis altura, DAP e lenho aos 24 meses apresentaram diferen?as estat?sticas superiores no cultivo intensivo para as tr?s esp?cies. As vari?veis biomassa seca total e folhas apresentaram diferen?as entre os m?todos de cultivo apenas para a esp?cie Nim. Para desrama artificial de folhas e total houve intera??o entre os fatores, em que a esp?cie e o tipo de cultivo influenciaram na quantidade desramada, havendo diferen?a significativa tamb?m entre as esp?cies e entre os tipos de cultivo, apenas o Sabi? n?o apresentou diferen?a entre os m?todos de cultivo. J? para galhos, houve diferen?a significativa entre as esp?cies e entre os tipos de cultivo, por?m n?o houve intera??o entre os fatores. Concluiu-se que o m?todo de cultivo do solo influencia na produ??o, crescimento, distribui??o de biomassa e quantidade de biomassa desramada artificialmente das esp?cies sabi?, ac?cia e nim de forma diferente. O m?todo de cultivo intensivo do solo influenciou positivamente a produ??o, crescimento e quantidade de biomassa desramada artificialmente das tr?s esp?cies.

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2018-08-13T14:28:07Z No. of bitstreams: 1 texto completo.pdf: 1919645 bytes, checksum: f3f1a66595234af2326a364ca333e76e (MD5) / Made available in DSpace on 2018-08-13T14:28:07Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1919645 bytes, checksum: f3f1a66595234af2326a364ca333e76e (MD5) Previous issue date: 2016-05-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Invasões biológicas são consideradas uma das maiores ameaças à biodiversidade dos ecossistemas, atuando em mudanças nas regras de montagem das comunidades vegetais. Acácias australianas são frequentemente associadas à diminuição da riqueza de espécies nativas, pela inibição do estabelecimento de suas plântulas através da competição ainda na fase de estabelecimento, levando não só a uma redução do número de espécies, como também de suas abundâncias. As hipóteses levantadas neste trabalho foram as seguintes: a invasão biológica por Acacia mangium ocasiona perda de diversidade taxonômica de espécies nativas e diminuição da radiação solar no substrato herbáceo- arbustivo nas áreas invadidas com vegetação de Mussununga (cap i); a presença da Acacia mangium causa alterações sobre as regras de montagem das comunidades de Mussunungas (cap ii); e a riqueza e diversidade de espécies aumentará a medida que as condições ambientais restritivas (estresse hídrico, nutricional e de luz), ao longo do gradiente fisionômico, tornem-se mais amenas, aumentando o conjunto de estratégias que possibilitam o estabelecimento e permanência das espécies na vegetação de Mussununga (cap iii). O estudo foi conduzido em áreas com vegetação de Mussununga, nos municípios de Alcobaça, Caravelas e Linhares, constituindo um tipo de vegetação savânica sobre solos arenosos, pobres em nutrientes, associados à Floresta Ombrófila Densa de Terras Baixas, restritas ao sul da Bahia e norte do Espírito Santo. Foram selecionadas seis áreas com fisionomia gramíneo-lenhosa, sendo três invadidas (BA) e três não-invadidas (ES) por Acacia mangium. Na Bahia, foram alocadas 10 parcelas circulares com três metros de raio, em cada Mussununga, sendo cinco com Acacia no centro e cinco com Marcetia taxifolia (espécie controle), constituindo 30 parcelas. No Espírito Santo, a amostragem foi idêntica, porém, em substituição à leguminosa invasora, a Andira cf. ormosioides foi selecionada (controle da Acacia no ES), por apresentar características estruturais semelhantes à Acacia, além de ser uma leguminosa pertencente a um gênero fixador de nitrogênio atmosférico (N 2 ). Nossos resultados revelaram que: (i) a Acacia mangium elevou os níveis das diversidades taxonômica e filogenética da vegetação de Mussununga quando comparados às áreas não invadidas; (ii) a estrutura filogenética revelou agrupamento das áreas invadidas, indicando que as comunidades são estruturadas por filtros ambientais, apresentando maior quantidade de nichos vagos; (iii) a sobredispersão nas áreas não-invadidas, apontou uma maior quantidade de nichos preenchidos nas comunidades, com a facilitação atuando na estruturação das comunidades; (iv) o regime de luz revelou que a Acacia mangium aumenta o nível de sombreamento, prejudicando às espécies nativas adaptadas à forte radiação de luz solar. Dessa maneira, concluímos que: (i) a invasão por Acacia mangium aumentou a diversidade de comunidades nativas, provavelmente pelo tempo de residência da espécie na Mussununga; (ii) as leguminosas invasora e nativa são facilitadoras das espécies nativas de Mussununga pelo aumento das diversidades taxonômica e filogenética, bem como pelo sombreamento das espécies nativas, adaptadas à alta incidência de luz solar, ocasionados pela copa densa da Acacia mangium. Relacionado às fisionomias, foram alocadas cinco parcelas circulares em cada uma das áreas, constituindo 25 parcelas. Foi realizado contagem de indivíduos das espécies, bem como coleta de solo nas parcelas. Os resultados apontaram para formação de três grupos distintos, separados por aspectos abióticos edáficos e de luz: (i) Arborizada Típica e Florestada; (ii) Arborizada Aberta e Gramíneo lenhosa de Bonnetia; (iii) Ilhas. Apesar da diversidade taxonômica não ter revelado diferenças significativas entre as fisionomias, pudemos observar que: (i) a riqueza de espécies está concentrada nas áreas que apresentam maior complexidade estrutural e que sofrem menor estresse abiótico por luz, nutrientes e escassez ou excesso de água; (ii) a proporção de areia grossa em comparação com areia fina do solo, constitui um fator determinante da distribuição das espécies nas fisionomias; e (iii) os fatores abióticos de luz e água, são filtros ambientais severos que limitam o estabelecimento das espécies que não são adaptadas às condições adversas da Mussununga. / Biological invasions are considered one of the greatest threats to biodiversity in ecosystems, acting on changes in the assembly rules of plant communities. Australian Acacias are often associated with low richness of native species, by inhibiting their establishment of plantlets through competition still in the establishment phase, leading not only to a reduction in the number of species as well as their abundance. The hypotheses raised in this work were as follows: the biological invasion by Acacia mangium causes taxonomic diversity loss of native species and decreased solar radiation in the herbaceous and shrub substrate in areas invaded with Mussununga vegetation (i); the presence of Acacia mangium causes changes on the assembly rules of the communities of Mussunungas (ii); and (iii) the richness and diversity of species will increase as the restrictive environmental conditions (water stress, nutritional and light) along the physiognomic gradient, become warmer, increasing the set of strategies that enable the establishment and permanence of species in Mussununga vegetation. The study was conducted in areas with Mussununga vegetation in the municipalities of Alcobaça, Caravelas and Linhares, being a type of savanna vegetation on sandy soils poor in nutrients, associated with dense rain forest of Lowlands, restricted to the south of Bahia and north the Holy Spirit. Six areas were selected with grassy-woody face, three invaded (BA) and three non-invaded (ES) by Acacia mangium. In Bahia, they were allocated 10 circular plots with three meters radius in each Mussununga, five with Acacia in the center and five Marcetia taxifolia (control species), constituting 30 plots. In the Espírito Santo, the sample was identical, however, to replace the invasive legume, the Andira cf. ormosioides was selected (Acacia control in ES) due to structural features similar to Acacia, besides being a legume belonging to a genre fastener atmospheric nitrogen (N2). Our results showed that: (i) the Acacia mangium raised levels of taxonomic and phylogenetic diversity of Mussununga vegetation when compared to areas not invaded; (ii) the phylogenetic structure revealed grouping of the invaded areas, indicating that communities are structured by environmental filters, with higher amount of vacant niches; (iii) the over-dispersion in the areas non-invaded, pointed a greater amount of filled niches in communities, facilitating working in the structuring of communities; (iv) the light regime revealed that the Acacia mangium increases shading level damaging to native species adapted to the strong radiation of sunlight. Thus, we conclude that: (i) invasion by Acacia mangium increased diversity of native communities, probably due to the species residence time in Mussununga; (ii) the invasive and native legumes are facilitative of native species Mussununga by higher taxonomic and phylogenetic diversity, as well as the shading of native species adapted to the high incidence of sunlight, caused by dense canopy of Acacia mangium. Related to physiognomy, five circular plots were allocated to each of the areas, constituting 25 installments. Count was conducted of individuals of the species, and soil collected in installments. The results indicated formation of three distinct groups, separated by abiotic edaphic aspects and light: (i) Closed Savanna and Woodland; (ii) Open Savanna and Savanna; (iii) Park Savanna. Despite the taxonomic diversity have not revealed significant differences between the physiognomies, we observed that: (i) the species richness is concentrated in areas with greater structural complexity and suffer less stress abiotic for light, nutrients and shortage or excess of water; (ii) the proportion of coarse sand in comparison with fine sand soil, is a determining factor in the distribution of species in the physiognomies; and (iii) the abiotic factors of light and water, are severe environmental filters that limit the establishment of species that are not adapted to the harsh conditions of Mussununga.

Memoria para optar al Título Profesional de Ingeniera Agrónoma mención Manejo de Suelos y Aguas / Desde el año 1996 se encuentra en desarrollo una investigación de agroforestería con cosecha de agua en el secano interior de la Región Metropolitana. Para ello se establecieron parcelas de 11x15 m con los siguientes tratamientos con tres repeticiones: AL plantación de Acacia saligna y siembra el primer año de Avena sativa; ALE plantación de A. saligna y siembra el primer año de Avena sativa, con dos tercios de área de escurrimiento; A plantación de A. saligna; AE plantación de A. saligna con dos tercios de área de escurrimiento; además, se consideró un testigo (T) con pradera mediterránea anual (PMA), equivalente al área de escurrimiento (11x10 m). Se midió la materia orgánica (MO), pH en agua y KCl, además de nitrógeno total (Nt), fósforo total (Pt) y potasio total (Pt) a los tiempos 4, 8 y 12 años, y a profundidades de 0-10; 10-20; 20-30 y 30-40 cm. Este trabajo corresponde a la tercera evaluación en el tiempo, realizada el año 2008. Los resultados indican que todos los tratamientos presentaron valores mayores en todas las propiedades con respecto al testigo, demostrando que al aplicar tecnologías agroforestales se mejoran las propiedades químicas del suelo y el rendimiento de la PMA. El tratamiento ALE es el que presentó los contenidos totales de macronutrientes más altos para este mismo año, mientras que el tratamiento A presentó los valores más bajos. A través de los años, los tratamientos con escurrimiento (ALE y AE) fueron más estables y presentaron mayores valores, por la mejor condición que genera el escurrimiento. En cuanto al pH, los valores son significativamente mayores en los primeros centímetros, debido al efecto tampón que genera la MO. Para el Nt, éste tiende aumentar en los tratamientos a través de los años; en el caso del Pt, su contenido va disminuyendo en profundidad y a través de los años; el contenido de Kt es muy estable entre los tratamientos y en profundidad, tendiendo a aumentar con los años. Para el caso del desarrollo de la PMA, bajo la influencia de A. saligna, los tratamientos con labranza (ALE y AL) tuvieron un mejor desarrollo, mientras que los tratamientos con escurrimiento (ALE y AE) tuvieron mayor acumulación de hojarasca de la Acacia.

Memoria para optar al Título Profesional de Ingeniero Forestal

The objective of the following study was threefold: to conduct a homoeopathic drug proving of Acacia xanthophloea 30CH on healthy individuals in order to elucidate the totality of signs and symptoms produced by the drug substance; to analyse the signs and symptoms gathered from the proving, collate the data, and convert the symptoms into materia medica symptoms and rubrics; to compare the symptoms of the proving to the doctrine of signatures. Methodology This proving study was a double-blinded, placebo controlled study. Thirty provers or participants were recruited for the study and the sample size was divided equally between two researchers (A. Gobind and G. Zondi). The sample was randomly divided into two groups, with one group receiving an active substance (verum group) and the other group receiving a placebo (control group). Amongst the 30 provers, 24 participants received verum and six received placebo. Each prover was given a journal to record their symptoms, a pen and nine powders. The duration of this proving study was six weeks including the first week of baseline during which time each prover was required to record their symptoms before taking the proving substance. This procedure was clearly explained to each prover and an information sheet with detail explanation of the proving procedure was provided and informed consent obtained. A thorough case history was taken in the initial consultation and physical examinations to ensure that individuals participating met the inclusion criteria and were healthy. Results Information derived both researchers was combined and the extraction of signs and symptoms then commenced. The symptoms were translated into materia medica and repertory format and graded accordingly. Thereafter the symptoms that emerged from the study were discussed and compared with the doctrine of signatures of Acacia xanthophloea. Provers experienced a wide range of symptoms mentally and emotionally e.g. anger, poor concentration and focus, disconnected feeling, depression, stress, anxiety, antisocial/ aversion to company, tranquillity. A large number of physical symptoms were noted by provers e. g. headaches, ailments of extremities (joint pain, weakness), female related symptoms (irregular menses, decrease/ increase libido etc.), eye symptoms, skin symptoms and general symptoms. The comparison of the symptoms of Acacia xanthophloea 30CH to the doctrine of signatures of the tree Acacia xanthophloea illustrated certain similarities, especially with regard to skin symptoms, eye symptoms, gastrointestinal symptoms and headaches. Conclusion The proving substance Acacia xanthophloea 30CH did produced signs and symptoms when given to healthy individuals as hypothesised. The symptoms when compared to the doctrine of signatures of the acacia xanthophloea tree did show correlation as hypothesised. / M

>Magister Scientiae - MSc / Invasive alien plants (IAPs) are often reported to use more water than indigenous plants. Inaddition, IAPs have an ability to adapt to harsh environmental conditions and they tend to spread at rapid rates, thereby threatening the country’s water resources, agricultural land, and biodiversity. Much of South Africa is expected to get drier in future due to climate change and the new climatic conditions are also predicted to accelerate the rate at which alien plants will spread. Approximately 10 million hectares are currently estimated to have been invaded by alien plants in South Africa, with an estimated average annual rate of spread of more than 5%. The first objective of this study was to compare the water use by deep rooted tree species which include invasive alien Prosopis (sp) trees and the co-occurring indigenous A. karroo. These trees are growing in a flood plain of a groundwater dependent catchment in the Northern Cape Province. Both species are dependent on groundwater and thus compete with local communities for this resource. The second objective was to determine the sources of water that the trees were using in order to understand the impacts of each species on groundwater resources. Transpiration was measured using the heat ratio method of the heat pulse velocity sap flow technique while the volumetric soil water content was monitored at several depths down the soil profile using automated capacitance soil water content probes. Weather data was collected using an automatic weather station. Stable isotopes of oxygen and hydrogen from plant, soil and groundwater samples were analysed to determine the sources of water used by the trees. Average tree density was approximately 613 stems per hectare for Prosopis compared to about 100 stems per hectare for A. karroo. Comparative measurements of water use shows that the annual stand level transpiration from Prosopis invasions was approximately 353 mm/year while that from A. karroo was only about 137 mm/year. Differences in stand transpiration were a result of the higher plant density for Prosopis than A. karroo. There were no significant differences in the transpiration rates of the two species for trees with a similar transpiring leaf area. Application of a two compartment linear mixing model for the oxygen isotope ratio during the peak transpiration period in summer showedthat Prosopis derived 23% of its water from the unsaturated zone and 77% from the saturated zone. A. karroo on the other hand derived 53% of its water from the unsaturated zone and47% from the saturated zone. Diurnal fluctuations in groundwater levels were strongly related to the transpiration dynamics of both species. This supports the observation that these deep rooted trees have substantial impacts on groundwater at the study site. Root sap flow patterns of Prosopis showed evidence of hydraulic redistribution wherein the groundwater abstracted by the tap roots was deposited in the shallow soil layers by lateral roots. However, the root sap flow patterns of A. karroo growing adjacent to the Prosopis did not show this phenomenon.

From Summary: The structural elucidation of condensed tannins, which are considered to consist of C₁₅-flavan units, presents certain difficulties. These tannins occur in extremely complex mixtures, and their isolation is complicated by their susceptibility to oxidative denaturation. Limitations in the formation of significant degradation products add to these problems. Since condensed tannins of black wattle bark yield anthocyanidins on treatment with mineral acids, they are considered to be proanthocyanidin in character. For this reason the initial approach to the investigation of the structures of condensed tannins was by way of the synthesis of novel 7-hydroxyflavan-3,4-diols having a low degree of hydroxyl substitution. Submission of these to modern physical techniques such as nuclear magnetic resonance (n.m.r.) spectroscopy would yield valuable data regarding the chemical shifts and coupling constants of heterocyclic and benzenoid protons which may be used for subsequent work on more highly hydroxylated diols, biflavanols and finally the condensed tannins themselves.