The adoption of precision agriculture techniques finds great limitation because of the high cost, not always guaranteeing the expected economic return. Among the consequence of this elevated cost it is the restriction use of this technology in small farmers, characterized by the family farm. The present work approaches a bibliographical study about the situation of the family farm in Brazil, pointing to regional focuses. In order to complement this study was made a diagnosis on the existing agricultural machines park and the mechanization used intensity in the state of Rio Grande do Sul, aiming a reflection about the role of the agricultural machine industries for small farmers. This work was dedicated to apply precision agriculture techniques in a small farmer where an area of 10,9 hectares was managed with precision agriculture tools and appropriate information technology to the socioeconomic farmer profile. In order to reach this general objective it was proposed the following specific objectives: a) to identify the horizontal spatial variability of the soil attributes through fertility maps; b) to apply fertilizers in different doses for each handling zones; c) to measure soil resistance to penetration and wheat leaf chlorophyll; d) to make yield map; e) to take note of production costs and to elaborate liquid revenue map for wheat culture; f) to evaluate performance of agricultural machines using GPS tracker. As some results, it was found horizontal spatial variability in soil for phosphorus and potassium and chlorophyll in wheat leaf; it was possible to apply different quantities of fertilizer using seeding and centrifugal broadcaster spreaders without automatic variable rate. In this area, the average of wheat yield was 2427 kg.ha-1, changing from 1915 to 3151 kg.ha-1. Considering the relationship between productivity and production costs, the liquid revenue varied from R$ 14,00 to 358,00 per hectare and had average of R$ 183,48 per ha. The individual crossing among digital models evidenced correlation of 48,6% between productivity and liquid revenue. In general way, precision agriculture tools can help the farmer to know better and more precisely each part of area destined to agricultural activity. It allows to increase the production efficiency through a better soil handling and rational use of the inputs, reducing costs, and other times, increasing productivity. / A adoção de técnicas associadas à agricultura de precisão encontra grande limitação devido ao seu elevado custo implantação, nem sempre garantindo o retorno esperado. Entre as conseqüências deste elevado custo está a restrição do uso dessa tecnologia em pequenas propriedades, caracterizadas pela agricultura familiar. O presente trabalho inicialmente aborda um estudo bibliográfico sobre o retrato da situação da agricultura familiar no Brasil e apontando para enfoques regionais. Complementam este estudo um diagnóstico sobre a frota de máquinas agrícolas existente e os índices de mecanização nas diversas regiões do Rio Grande do Sul, levando à reflexão sobre o papel da indústria de máquinas agrícolas para pequenas propriedades. O trabalho foi dedicado à aplicação de técnicas de agricultura de precisão em uma pequena propriedade, onde se preocupou em gerenciar uma área de 10,9 hectares com ferramentas e tecnologia de informação mais adequada ao perfil agrosocioeconômico do produtor. Para atender este proposto, os objetivos específicos foram: a) identificar a variabilidade espacial horizontal dos atributos de solo através de mapas de fertilidade; b) aplicar fertilizantes em diferentes doses por zonas de manejo; c) medir resistência à penetração do solo e clorofila na folha de trigo; d) confeccionar mapa de produtividade; e) apontar os custos de produção e elaborar mapa de receita líquida da cultura do trigo; e f) avaliar o desempenho operacional das máquinas agrícolas através de rastreamento por GPS. Entre os principais resultados, encontrou-se variabilidade horizontal dos teores de fósforo e potássio no solo e de clorofila no trigo; foi possível aplicar diferentes doses de fertilizantes utilizando semeadora e distribuidor centrífugo de taxa fixa. A produtividade média de trigo na área foi de 2427 kg.ha-1, oscilando entre 1915 e 3151 kg.ha-1. Considerando a relação produtividade e custo, a receita líquida variou de R$ 14,00 a 358,00 por hectare e em média R$ 183,48 por ha. O cruzamento individual entre modelos digitais evidenciou correlação de 48,6% entre produtividade e receita líquida. De uma forma geral, as ferramentas de agricultura de precisão podem ajudar ao produtor a conhecer melhor e mais detalhadamente cada parcela de sua área destinada à atividade agrícola, permitindo aumentar a eficiência produtiva através do manejo e do uso racional dos insumos, diminuindo custos, e por vezes, aumentando a produtividade.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / With the advance the adoption of precision agriculture in Brazil, growing use the technological tools georeferenced soil sampling and crop yield. Relations and crossing data information between these two tools can assist in improving the management of crops through specific recommendations of each element with reduced costs, efficient use of inputs, increasing productivity and profitability of crops. The objective of this study was to evaluate the influence of soil chemical properties on grain yield of soybean and corn in two experimental fields southern Brazil through principal component analysis and hierarchical cluster. The research happened in two experimental areas of 132 and 124 hectares in typical Oxisol. The soil samples were taken with a grid sampling of one hectare in the 0-0.10 m layer. The yields of the cultures were related at the same point each soil analysis using the annual average productivity at a radius of 25 m around each sampling point. At the first experimental area of 132 hectares, were investigated yield maps soybean harvest crop 2008/09; soybean crop 2009/10; soybean crop 2010/11 and corn crop 2011/12. In the second study area of 124 hectares, were investigated yield maps soybean harvest crop 2009/10, corn harvest 2010/11 and soybean crop 2011/12. The selection of yield maps followed the criterion to evaluate crops with less than two years of the completion of soil sampling, where only occurred fertilization of crop maintenance. Both areas had high fertility, the first area to saturation (V) average 65.16% and 83.03% in the second area. At the first experimental area the increase in productivity is being explained by the increase of the attributes: saturation of calcium and magnesium in the cation exchange capacity (Sat Ca, Mg Sat), V, and the calcium: magnesium (Ca: Mg). In the second experimental area the increase attribute chemical Sat Mg committed crop yields. In both experiments the elevation of attributes Sat Ca, V and Ca: Mg contributed to raising crop yields. The balance of cations in the exchange complex was the chemical attributes that best explained the variability in crop investigated. / Com o avanço da adoção da agricultura de precisão no Brasil, cresce a utilização de ferramentas tecnológicas de amostragem de solo georreferenciadas e mapas de produtividade das culturas. As relações e o cruzamento de dados entre as informações destas duas ferramentas podem auxiliar no aprimoramento do manejo das lavouras através de indicações específicas de cada elemento com redução de custos, uso eficiente de insumos, aumento da produtividade e rentabilidade das culturas. O objetivo desse trabalho foi avaliar a influência de atributos químicos do solo na produtividade das culturas de soja e milho em duas áreas comerciais no planalto do RS, através da análise de componentes principais e o agrupamento hierárquico - cluster. A investigação ocorreu em duas áreas experimentais de 132 e 124 ha em Latossolo Vermelho distrófico típico. As amostragens de solo foram realizadas baseadas em uma malha regular de 100 metros por 100 metros na camada de 0-0,10 m. As produtividades das culturas foram relacionadas no mesmo ponto de cada análise de solo utilizando-se a média de produtividade anual em um raio de 25 m ao redor de cada ponto amostral. Na primeira área experimental de 132 ha, foram investigados os mapas de colheita de soja-safra 2008/09; soja-safra 2009/10; soja-safra 2010/11 e milho-safra 2011/12. Na segunda área investigada, de 124 ha, foram estudados os mapas de colheita de soja-safra 2009/10; milho-safra 2010/11 e soja-safra 2011/12. A escolha dos eventos de colheita analisados seguiu o critério de avaliar safras com período inferior a dois anos da realização da amostragem de solo, em que apenas ocorreram as adubações de manutenção das culturas. Ambas as áreas apresentavam fertilidade elevada, sendo a primeira com a saturação de bases (V) média de 65,16% e a segunda com 83,03%. Na primeira área experimental, o acréscimo de produtividade está sendo explicado pela elevação dos atributos: saturação de cálcio e de magnésio na capacidade de troca de cátions (Sat Ca; Sat Mg), V e relação cálcio: magnésio (Ca:Mg). Na segunda área experimental, a elevação do atributo químico Sat Mg comprometeu a produtividade das culturas. Em ambos os experimentos a elevação dos atributos Sat Ca, V e Ca: Mg contribuíram para elevar a produtividade das culturas. O equilíbrio de cátions no complexo de troca foi o atributo químico que melhor explicou a variabilidade da produtividade das culturas investigadas.

This work aimed to apply geostatistical analysis to verify the existence of spatial dependence in the distribution of arboreal species, and variables related on parcels installed in the National Forest of São Francisco de Paula, RS, in the Rio Grande do Sul Continuous Forest Inventory, in 2000. For this research, the plots 1537, 1538, 1539 and 1540 were select. To analyze the existence of spatial dependence of arboreal species and related variables, the "adjustment to feeling" semivariograms were conducted, obtaining the parameters of nugget effect (C0), level (C0 + C), range (a), coefficient of determination (R ²), Degree of spatial dependence (C/C0 + C) and sum of squared residuals (SSR). To check the quality of the adjustments, the cross-validation has been used. The geostatistical software GS + was used to select the models, describe the spatial dependence and timely realization of ordinary kriging interpolation of arboreal species and other variables. The results showed an elevated degree of spatial dependence on the species Podocarpus lambertii Klotzsch ex Endl (1538); Vernonia discolor (Spreng.) Less (plot 1538); Cryptocarya moschata Nees (1539); Matayba elaeagnoides Radlk (plot 1539); Shannon index - Weaner; and moderate to Myrciaria floribunda (West ex Willd.) (1537); Number of individuals from the plot 1540 (plot 1540). The other variables had no structured variance, indicating that the variables have a fully random distribution and it is not possible to obtain surfaces interpolated by kriging. This event is probably bound to the spatial dependence break, resulting from the distortion of the original forest formation due to the history of forest exploitation process. / Este trabalho teve como objetivo aplicar análise geoestatística para verificar a existência de dependência espacial na distribuição de espécies arbóreas, e de varáveis relacionadas, nas parcelas instaladas na Floresta Nacional de São Francisco de Paula, RS, na ocasião da realização do Inventário Florestal Contínuo do Rio Grande do Sul, no ano de 2000. Para este trabalho, foram selecionadas as parcelas 1537, 1538, 1539 e 1540. Para análise da existência de dependência espacial das espécies arbóreas e variáveis relacionadas, foram realizados ajuste à sentimento de semivariogramas, obtendo-se os parâmetros efeito pepita (C0), patamar (C0 + C), alcance(a), coeficiente de determinação (R²), Grau de dependência espacial (C/C0 + C) e soma dos quadrados dos resíduos (SQR). Para verificar a qualidade dos ajustes foi utilizada a validação cruzada. O programa geoestatístico GS+, foi utilizado para seleção dos modelos, descrição da dependência espacial e realização da interpolação por krigagem ordinária pontual das espécies arbóreas e demais variáveis. Os resultados obtidos apresentaram grau de dependência espacial forte para espécie Podocarpus lambertii Klotzsch ex Endl (1538); Vernonia discolor (Spreng.) Less (parcela 1538); Cryptocarya aschersoniana Mez (1539); Matayba elaeagnoides Radlk (parcela 1539); índice de Shannon Weaner; e moderada para a Myrciaria floribunda (West ex Willd.) (1537); Número de indivíduos da parcela 1540 (parcela 1540). As demais variáveis apresentaram ausência de variância estruturada, indicando que as variáveis apresentam uma distribuição totalmente aleatória, não sendo possível obter superfícies interpoladas por krigagem. Este acontecimento provavelmente está vinculado a quebra de dependência espacial, resultante do processo de descaracterização da formação florestal original, em consequência do histórico de exploração da floresta.

Precision agriculture applied to vitiviniculture can bring several advantages to vitis crop production with positive effects on grape and wine quality. This study s objective was to put into practice precision vtiticulture, aiming to improve the administration and management of vinifera grapes. This research was carried out in a commercial vitis cropland with 2.4 ha located in Encruzilhada do Sul (RS) close to RS/BR km 471. In this area, sandy clay loam Palleudult soil prevails. Sampling for the purposes for soil characterisation was carried out in 0-0,2 m depth. The soil attributes determined were: pH, SOM, texture, Ca, Mg, Al, N, MO, K and P, and the plant attributes were: productivity, alcoholic potential and tartaric acid, using a 35 X 35m grid. Data were analyzed through geostatistics by interpolation technique of kriging. The data of yield and enological parameters were obtained by manual harvest in georeferenced points. Grape data were collected during the harvest in 2007 and 2008 seasons. Soil and plant data were submitted to statistical analysis and basic geostatistic. Spatial variability of soil chemical attributes in the area behaved in accordance with the nutrient evaluated. pH showed low variability, clay, Ca, Mg, and N, showed median variability while MO, P and K , a high variability was found, and for Al, very high. In 2007 harvest, tartaric acid and alcoholic potential showed low variability, number of bunches per plant and weight per bunch presented median variability while weight per plant showed high variability. In 2008 harvest, alcoholic potential showed low variability, while tartaric acid, number of bunches per plant, weight per plant, weight per bunch and number of gems showed median variability. The 35 X 35 m sampling grid has shown itself adequate for soil attributes excepting clay, which obtained a 30.06 m distance reach. In 2007 harvest, the alcoholic potential was the plant attribute that showed smaller reach n the area, 18.42 m. In 2008 harvest, all the plant attributes studied showed a below 35 m reach. The correlation analysis has revealed itself significant among nitrogen and alcoholic potential in 2007 harvest. In 2008 harvest, phosphorus and potassium showed significant correlation with alcoholic potential. The comparison of the demand for the application of fertilizer at varied rate, with application at steady rate of lime, phosphorus and potassium was based on the soil sampling. In the case of lime, there was a 700 kg saving of it with varied rate application, the same was not observed with phosphorus and potassium, which would increase the product quantity if implemented this way, this happens because the levels of them in the soil are appropriate. The adoption of precision viticulture can help the wine grower to know better and further the productive area, allowing to improve the quality and quantity of the vineyard. / O uso da agricultura de precisão aplicada à vitivinicultura pode trazer benefícios à cultura da vitis e à cadeia produtiva, com reflexos na qualidade da uva e do vinho. O objetivo deste estudo foi aplicar a vitivinicultura de precisão, visando aprimorar a gestão e o manejo de áreas produtivas de uvas viníferas. O estudo foi conduzido em um vinhedo comercial, numa área de 2,4 ha, destinado à fabricação de espumantes situada às margens da RS/BR km 471, em Encruzilhada do Sul-RS. Na área predominam solos classificados como Argissolo Vermelho distrófico. A amostragem para fins de caracterização do solo foram realizadas na profundidade de 0-0,2m. Os atributos de solo determinados foram: pH, SMP, Argila, Ca, Mg, Al, N, MO, K e P, e os atributos de planta foram produtividade, ácido tartárico e potencial alcoólico usando uma malha de amostragem de 35 X 35 m. Os dados foram analisados através da técnica de interpolação geoestatística por krigagem. Os dados de rendimento e parâmetros enológicos foram obtidos por colheita manual em pontos georreferenciados. Os dados de uva foram coletados durante a colheita nas safras 2007 e 2008. Os dados de solo e de planta foram submetidos à analise estatística básica e geoestatistica. A variabilidade espacial dos atributos químicos do solo na área comportou-se de forma distinta de acordo com o nutriente avaliado. O pH apresentou variabilidade baixa, a Argila, o Ca, o Mg, e o N, o apresentaram variabilidade média enquanto que a MO, o K e o P, a variabilidade encontrada foi alta, e para o Al muito alta. Na safra 2007, o ácido tartárico e o potencial alcoólico apresentaram variabilidade baixa, o número de cachos por planta e o peso por cacho apresentaram variabilidade média enquanto que o peso por planta apresentou variabilidade alta. Na safra 2008, o potencial alcoólico apresentou variabilidade baixa, enquanto que o ácido tartárico, o número de cachos por planta, o peso por planta, o peso por cacho e o número de gemas apresentaram variabilidade média. A malha de amostragem de 35X35m se mostrou adequado para os atributos de solo com exceção da argila, que obteve uma distância de alcance de 30,06m. Na safra 2007 o potencial alcoólico foi o atributo de planta que apresentou menor alcance na área, de 18,42 m. Na safra 2008, todos os atributos de planta estudados apresentaram alcance inferior a 35 m. A analise da correlação se revelou significativa entre o nitrogênio e o potencial alcoólico na safra 2007. Na safra 2008, o fósforo e o potássio mostraram correlação significativa com o potencial alcoólico. A comparação da demanda de aplicação de fertilizantes a taxa variada, com a aplicação à taxa fixa de calcário, fósforo e potássio foi feita com base na amostragem de solo. No caso do calcário observou-se uma economia de 700 kg do mesmo com aplicação a taxa variada, o mesmo não foi observado com o fósforo e com o potássio, que aumentaria a quantidade do produto caso fosse aplicado desta forma, isso se dá pelo fato dos teores dos mesmos no solo serem adequados. A adoção da vitivinicultura de precisão pode auxiliar o viticultor a conhecer melhor e mais detalhadamente a área produtiva, permitindo aprimorar a qualidade e quantidade do vinhedo.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The georeferenced soil sampling using sampling grids is the main strategy of precision agriculture (PA) to recognize the spatial variability of soil attributes, allowing manage them in site-specific. In this context, the objective of the work was to evaluate the efficiency of using different sizes of sampling grids in the characterization of spatial variability of chemical attributes in Oxisols managed with PA in Southern Brazil. Therefore, the work consists of three studies. In studies one and two were used 60 areas (6,046.55 ha), located in 23 counties of North region of Rio Grande do Sul (RS). The areas were sampled using regular grids of 100 x 100 m (20 areas), 142 x 142 m (20 areas) and 173 x 173 m (20 areas), being that 10 areas of each grid were collected from 0.00-0.10 m and 10 areas from 0.00-0.15 m. The spatial variability of acidity attributes (pHwater and base saturation) and bases related (Ca and Mg) (study one) and the levels of P and K (study two) were analyzed by descriptive statistics and geostatistics. In study three, was used an area of 41.96 ha, located in Boa Vista das Missões - RS, where was made the collect of soil in seven sizes of sample grids, 50 x 50 m, 75 m x 75, 100 x 100 m, 125 m x 125, 150 x 150 m, 175 m and 200 x 175 x 200 m, at depth of 0.00-0.10 m. The levels of P and K were analyzed by descriptive statistics and geostatistics, and the similarity of thematic maps was compared by the coefficient of relative deviation (CRD) and by Pearson correlation matrix (p <0.05). The areas of Oxisols managed with PA in RS, show moderate acidity and high fertility, with the exception of subareas that presents limiting P levels. Independently of the depth sampled, the grid sample sizes used in RS state, in general, are not efficient in capturing the different scales of variability in soil chemical properties. According as increase the sample grid the thematic maps of P (CRD: 24.0 to 36.2%) and K (CRD: 11.7 to 19.4%) show more dissimilar to those obtained in smaller grid (50 x 50 m) considered as reference. Thus, the reduction of sampling grid sizes increases the accuracy of the information generated through thematic maps, allowing to do prescriptions of lime and fertilizers on site-specific with greater efficiency, and should be recommended in future sampling plans of soil adopted in PA areas in Southern Brazil. / A amostragem georreferenciada de solo utilizando malhas regulares é a principal estratégia da agricultura de precisão (AP) para reconhecer a variabilidade espacial dos atributos de solo, possibilitando manejá-los em sítio-específico. Nesse contexto, o objetivo do trabalho foi avaliar a eficiência do uso de diferentes dimensões de malhas amostrais na caracterização da variabilidade espacial de atributos químicos em Latossolos Vermelhos manejados com AP no Sul do Brasil. Para tanto, o trabalho constitui-se de três estudos. Nos estudos um e dois utilizaram-se 60 áreas (6.046,55 ha), localizadas em 23 municípios da região Norte do Rio Grande do Sul (RS). As áreas foram amostradas utilizando malhas regulares de 100 x 100 m (20 áreas); 142 x 142 m (20 áreas) e 173 x 173 m (20 áreas), sendo que 10 áreas de cada malha foram coletadas de 0,00-0,10 m e 10 áreas de 0,00-0,15 m. A variabilidade espacial dos atributos de acidez (pHágua e saturação por bases) e bases relacionadas (Ca e Mg) (estudo um) e dos teores de P e K (estudo dois) foram analisadas por meio da estatística descritiva e geoestatística. No estudo três, utilizou-se uma área de 41,96 ha, localizada em Boa Vista das Missões RS, onde foi realizada a coleta de solo em sete dimensões de malha amostral, 50 x 50 m, 75 x 75 m, 100 x 100 m, 125 x 125 m, 150 x 150 m, 175 x 175 m e 200 x 200 m, na profundidade de 0,00-0,10 m. Os teores de P e K foram analisados por meio da estatística descritiva e da geoestatística, e a similaridade dos mapas temáticos foi comparada pelo coeficiente de desvio relativo (CDR) e pela matriz de correlação de Pearson (p <0,05). As áreas de Latossolos Vermelhos manejadas com AP no estado do RS apresentam moderada acidez e alta fertilidade, com exceção de locais que apresentam teores limitantes de P. Independente da profundidade amostrada, as dimensões das malhas amostrais utilizadas no RS, em geral, não são eficientes em captar as diferentes escalas de variabilidade dos atributos químicos do solo. À medida que aumenta a malha amostral os mapas temáticos de P (CDR: 24,0 a 36,2%) e K (CDR: 11,7 a 19,4%) mostram-se mais dissimilares aos obtidos na menor malha (50 x 50 m) considerada como referência. Desta forma, a redução da dimensão da malha amostral aumenta a acurácia das informações geradas por meio de mapas temáticos, permitindo realizar prescrições de corretivos e fertilizantes em sítio-específico com maior eficiência, e devem ser preconizadas em futuros planos de amostragem de solo adotados nas áreas de AP no Sul do Brasil.

Cette étude a pour but d'identifier les principales maladies coralliennes, de quantifier leurs prévalences sur les récifs de la Réunion, d'Afrique du Sud et de Mayotte et de déterminer leurs variations spatiales et saisonnières. Les résultats ont révélé la présence de six grands types de maladies coralliennes. Les prévalences totales moyennes des maladies ont été plus élevées à la Réunion (7.5 ± 2.2%) qu'en Afrique du Sud (3.9 ± 0.8%) et qu'à Mayotte (2.7 ± 0.3%). Les genres coralliens Acropora et Porites ont été les plus vulnérables aux maladies dans les trois régions étudiées. Des variations spatiales et saisonnières ont été détectées pour la maladie de la bande noire (BBD) et les syndromes blancs (WS) à la fois à la Réunion et en Afrique du Sud avec des prévalences plus élevées sur les récifs peu profonds et pendant la saison chaude. Ce travail a également pour but de caractériser deux maladies non décrites à ce jour : le syndrome des patches blancs (PWPS) et le syndrome du patch noir (PBPS) chez Porites. PWPS, observé à fois à la Réunion, en Afrique du Sud et à Mayotte est caractérisé par d'importantes fragmentations tissulaires généralement associées à des corps ovoïdes basophiles ressemblant à des agrégats bactériens. L'analyse bactérienne a révélé une grande variabilité entre les tissus infectés et sains. L'identification des pathogènes responsables de PWPS a également été réalisée en laboratoire. Sur les 14 souches bactériennes sélectionnées et testées, seule la P180R, génétiquement proche de Vibrio tubiashii a généré des signes de PWPS. Pour finir, PBPS, une forme atypique de BBD a été observée sur les récifs de la Réunion. Les suivis réalisés ont montré des variations spatiales et saisonnières avec des prévalences plus élevées sur le platier et pendant l'été. L'histologie a mis en évidence la présence de cyanobactéries et de corps basophiles dans les tissus infectés du corail. L'analyse génétique a révélé la présence d'une plus grande diversité de taxons dans les tissus infectés par PBPS que dans les tissus sains représentés par le genre Vibrio. / During the past two decades, the emergence and spread of infectious diseases have caused substantial declines in the biodiversity and abundance of reef-building corals. Despite their increased global prevalence and virulence, little is known about coral diseases on Indian Ocean coral reefs. This study aims to fill this gap in knowledge by identifying the main coral diseases and quantify their prevalence at three localities Reunion, South Africa and Mayotte, determining their spatial distribution and seasonal variation. Principal findings of this study demonstrated the presence of six main coral diseases including black band disease (BBD), white syndromes (WS), pink line syndrome (PLS), growth anomalies (GA), skeleton eroding band (SEB) and Porites white patch syndrome (PWPS). The overall disease prevalence was higher in Reunion (7.5 ± 2.2%; mean ± SE) compared to South Africa (3.9 ± 0.8%; mean ± SE) and Mayotte (2.7 ± 0.3%; mean ± SE). Acropora and Porites were the genera most vulnerable to disease. Spatial variability was detected in both Reunion and South Africa with BBD and WS more prevalent on shallow than deep reefs. There was also evidence of seasonality in two diseases: BBD and WS, their prevalence being higher in summer than winter. Corals exhibiting signs of PWPS revealed extensive tissue fragmentation, generally associated with ovoid basophilic bodies resembling bacterial aggregates within the mesoglea of the body wall. Other organisms, including Cyanobacteria, Nematoda, Ciliata and endophytic algae, were also observed on diseased tissues and were generally associated with the dead epidermis and cell debris. Results of 16S rRNA sequence analysis revealed a high variability between bacterial communities associated with PWPS-infected and healthy tissues in Porites lutea. Several bacterial ribotypes affiliated to potential putative pathogens notably Shimia marina and Vibrio hepatarius were consistently found among the 16S rRNA sequences derived from the PWPS lesions, and absent and/or poorly represented in HT. Primary pathogens involved in the PWPS were also investigated in this study using traditional culturing techniques and laboratory infection trials. Of the 14 isolates selected for the inoculation trials, only the bacterial strain P180R mostly phylogenetically closely related8 to Vibrio tubiashii with its closest known sister taxon, V. hepatarius, was shown to cause signs resembling those of PWPS and satisfied the four Henle-Koch’s postulates. P180R displayed focalised and progressive tissue paling 12 h after inoculation and visible lesions of PWPS were observed 12 h thereafter. Signs of PWPS appeared on 90% of the exposed coral fragments (27 of 30) under controlled environmental conditions. Moreover, the virulence of this marine pathogen was tested and seemed to be strongly dependent on seawater temperature, resulting in significantly higher tissue loss at 30°C than 28°C and 26°C. Finally, a multidisciplinary approach involving field surveys, gross lesion monitoring, histopathology and 454-pyrosequencing was investigated to characterize an atypical form of BBD named PBPS. Histology revealed cyanobacterial penetration of the compromised tissue as well as the presence of basophilic bodies resembling bacterial aggregates in the living tissue, adjacent to the bacterial mat. Bacterial 16S rRNA sequences yielded a broader diversity of bacterial taxa in PBPS-infected tissues than in healthy tissue, represented by the genus Vibrio (24.9%), followed by sulfate-reducers or sulfide-oxidizers such as Desulfovibrio (20%), Clostridium (12.9%) and Arcobacter (9.9%). PBPS appears to be a multi-stage disease triggered by cyanobacterial invasion and resulting in secondary infections by environmental bacteria that grow in mucus-like decomposing tissue.

L’usage répété d’isoproturon (IPU) en agriculture pour contrôler développement de plantes adventices dans les cultures céréalières a non seulement abouti à la contamination du sol et des ressources en eaux mais également à l’adaptation de la microflore du sol à la dégradation accélérée de cet herbicide appartenant à la famille des phénylurées. A l’heure actuelle, les mécanismes microbiens impliqués dans cette adaptation ne sont pas encore parfaitement élucidés. Dans ce contexte, l’objectif de cette étude était d’explorer les processus et les facteurs impliqués dans la biodégradation de l’isoproturon, et ce, depuis l’échelle agricole de la parcelle jusqu’à celle des gènes codant cette fonction dans des populations microbienne dégradantes.L’étude réalisée à partir d’une parcelle expérimentale du domaine d’Epoisses, cultivée selon une rotation blé d’hiver/ orge / colza, a montré que, suite à l’usage répété d’IPU, la microflore du sol s’était adaptée à sa minéralisation. Des analyses réalisées à l’aide d’outils statistiques et géostatistiques ont révélé l’existence d’une variabilité spatiale de la minéralisation de l’IPU au sein de la parcelle agricole. Celle-ci s’est révélée être non seulement corrélée avec différents caractéristiques physicochimiques du sol (C/N, CEC, …) mais également avec le plan d’épandage des pesticides au cours de la rotation culturale.Afin de mieux étudier les mécanismes moléculaires responsables de la minéralisation de l’IPU, une culture bactérienne ainsi qu’une souche (Sphingomonas sp. SH) minéralisant l’IPU ont été isolées par enrichissement à partir de deux sols différents, tous deux adaptés à la biodégradation accélérée de l’IPU. La culture bactérienne et la souche pure ont toutes deux montré un métabolisme spécifique pour la dégradation de l’IPU, étant capables de dégrader l’IPU et ses principaux métabolites mais aucun des autres herbicides de la famille des phénylurées. La culture bactérienne et la souche présentaient une activité dégradante optimale à pH7,5 et étaient affectées par des pH inférieurs et supérieurs à cette valeur optimale. Sur la base des métabolites accumulés lors de la dégradation de l’IPU, nous avons proposé que l’IPU serait dégradé par deux déméthylations successives, suivi par la coupure de la chaine urée aboutissant à l’accumulation de 4-isopropylaniline, et finalement la minéralisation du cycle phényl.Afin d’identifier les gènes impliqués dans la minéralisation de l’IPU, une banque de clones BAC a été réalisée à partir de l’ADN génomique purifié de la culture bactérienne. Bien que le crible fonctionnel réalisé n’a pas permis d’identifier de BAC capable de dégrader l’IPU ou l’un de ses métabolites, un criblage moléculaire par PCR ciblant la séquence catA codant la catéchol 1,2-dioxygénase, nous a permis d’identifier trois BACs. Le pyroséquençage des ces 3 BACs et l’agrégation des séquences correspondantes ont permis d’identifier un fragment génomique de 33 kb présentant notamment l’opéron cat impliqué dans le clivage ortho du cycle phényl du catéchol. De ce fait nous avons émis l’hypothèse selon laquelle la 4-isopropylaniline formée lors de la dégradation de l’IPU pourrait être minéralisée par le clivage ortho du catéchol, un intermédiaire clef de la voie des beta-kétoadipates. Ceci nous a donc permis de proposer une voie métabolique pour la voie basse de la dégradation de l’IPU qui, jusqu’alors, n’avait pas encore été décrite. / Frequent use of phenylurea herbicide isoproturon (IPU) in agricultural fields has resulted not only in the contamination of the natural resources including soil and water but also in the adaptation of the soil microflora to its rapid degradation. However, up to now, the mechanisms underlying this microbial adaptation are not well elucidated. The aim of this study was to explore the processes and factors implicated in IPU degradation from the agricultural field to the genes coding for catabolic genes. The study carried out at the experimental field of Epoisses cropped with a winter wheat / barley / rape seed crop rotation indicated that as a result of its periodically repeated use, the soil microflora adapted to IPU mineralization activity. Further analysis using exploratory and geostatistical tools demonstrated the existence of spatial variability in IPU mineralization activity at the field scale which was correlated not only with several soil physico-chemical parameters like organic matter content, CEC and C/N ratio but also with the pesticide application plan over a three year crop rotation. In order to get further insight into underlying mechanisms, an IPU mineralizing bacterial culture and strain Sphingomonas sp. SH were isolated through enrichment cultures performed from two different adapted soils. Both had the catabolic activities highly specific for the mineralization of IPU and its metabolites but none of other structurally related phenylurea herbicides. IPU metabolic activity of both the mixed culture and the strain SH was found to be affected by pH with optimal activity taking place at pH 7.5. Based on the accumulation of different known metabolites during mineralization kinetics, IPU metabolic pathway was proposed to be initiated by two successive demethylations, followed by cleavage of the urea side chain resulting in the accumulation of 4-isopropylaniline, and ultimately the mineralization of the phenyl ring. In order to identify the genes involved in IPU degradation, BAC clone library was established from the genomic DNA of the bacterial culture. Although, the functional screening did not yield in identifying any BAC clone able to degrade IPU or its known metabolites, the PCR based screening led us to identify a cat gene cluster involved in ortho-cleavage of the phenyl ring of catechol through beta-ketoadipate pathway. Based on this finding, it was hypothesized that phenyl ring of 4-isopropylaniline formed during IPU transformation might be mineralized through ortho-cleavage of catechol. This finding allowed us to propose the lower IPU metabolic pathway which was not yet described.

Orientador: Rafael Montanari / Resumo: Na busca por soluções que otimizem as operações, auxiliem no planejamento e reduzam os custos operacionais no manejo do solo, a geoestatística tem sido aplicada em diversas áreas. Utilizando a geoestatística como ferramenta e forma de planejamento de manejo, o presente trabalho objetivou-se analisar economicamente a recuperação da fertilidade do solo de uma pastagem potencialmente degradada no cerrado brasileiro em dois sistemas de intervenção: convencional (SC) e agricultura de precisão (AP) e gerar informações por meio da análise de variabilidade e estabelecimento da estrutura de dependência espacial, a fim de auxiliar no planejamento de atividades agrícolas em seis cidades na província de El Oro, Equador. O trabalho foi realizado no ano agrícola de 2015/2016 na área experimental de sistemas de produção em bovinocultura de corte pertencente à Faculdade de Engenharia – UNESP, Campus de Ilha Solteira, São Paulo, Brasil e na Universidade Técnica de Machala (UTMACH), Machala, Equador. A recuperação no SC apresentou índice de lucratividade negativa (-1,32%) e no AP positiva (0,26%) proporcionando um preço de custo @-1 de R$ 155,52 e R$ 153,10 para o SC e AP, respectivamente. Comparando-se áreas cultivadas com AP e SC, é provável que se obtenha resultados mais confiáveis e com melhores perspectivas em maiores áreas de cultivo de forma a aumentar a rentabilidade do sistema. Na província de El Oro, o teor de Zinco obteve o maior coeficiente de determinação espacial. O pH se destaco... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A demand for solutions that optimize operations, support planning and reduce operational costs in soil management, geostatistics has been applied in several areas. Using geostatistics as a tool and management planning method, the present work aimed to economically analyze the soil fertility recovery of a potentially degraded pasture in the Brazilian cerrado in two intervention systems: conventional (CS) and precision agriculture (PA) and generate information through variability analysis and establishment of spatial dependence structure to assist in the planning of agricultural activities in six cities in El Oro province, Ecuador. The work was carried out in the 2015/2016 agricultural year in the experimental area of beef cattle production systems belonging to the Faculty of Engineering - UNESP, Ilha Solteira Campus, São Paulo, Brazil and the Technical University of Machala, Machala, Ecuador. The recovery in CS presented negative profitability index (-1,32%) and positive in PA (0,26%) providing a cost @ -1 price of R$ 155,52 and R$ 153,10 for CS and PA, respectively. Comparing cultivated areas with PA and CS, it is likely that more reliable results and better prospects will be obtained in larger cultivated areas in order to increase the profitability of the system. In El Oro province, the Zinc content obtained the highest coefficient of special determination, but low range, which may be influence by the numbers of pairs in the first Lag. The pH stood out as the major influence... (Complete abstract click electronic access below) / Doutor

Understanding the spatial and temporal dynamics of soil water and crop water stress within a field is critical for effective Variable Rate Irrigation (VRI) management. Proper VRI can result in improved protection of the crop from early onset of crop water stress while minimizing runoff and drainage losses. The objectives of this study are (1) to examine zone delineation for informing irrigation recommendations from volumetric water content (VWC) and field capacity (FC) to grow similar or greater wheat yields with less water, (2) evaluate the ability to model soil and crop water dynamics within a season and within a field of irrigated winter wheat, and evaluate the sensitivity of crop water stress, evapotranspiration and soil water depletion outputs within a water balance model with Penman-Monteith evapotranspiration (ET) in response to adjusted soil properties, spring volumetric water content (VWC), and crop coefficient model input values. Five irrigation zones were delineated from two years of historical yield and evapotranspiration (ET) data. Soil sensors were placed at multiple depths within each zone to give real time data of the VWC values within each soil profile. Soil samples were taken within a 22 ha field of winter wheat (Triticum aestivum ‘UI Magic’) near Grace, Idaho, USA multiple times during a growing season to describe the spatial variation of VWC throughout the field, and to assist in modeling soil water dynamics and crop water stress through energy balance and water balance equations. Spatial variation of VWC was observed throughout the field, and on a smaller scale within each zone, suggesting the benefit of breaking portions of the field into zones for irrigation management purposes. Irrigation events were triggered when soil sensors detected low values of VWC, with each zone receiving unique rates intended to refill to zone specific FC. Cumulative irrigation rates varied among zones and the VRI approach saved water when compared to an estimated uniform Grower Standard Practice (GSP) irrigation approach. This method of zone management with soil sampling and sensors approximately represented the VWC within each zone and proved beneficial with effective reduction of irrigation rates in every zone compared to an estimated GSP. As such, there was a delay in the premature onset of crop water stress throughout some areas of the field. Variability in soil properties and spring soil moisture were key in giving accurate values to the model in order to make proper VRI management decisions. When assessing the model sensitivity, changing the inputs such as FC, wilting point (WP), total available water (TAW), spring VWC and crop coefficient (Kc) by -4 to +4 standard deviations away from their spatially average values, impacted the outputs of the model, with Kc having a large impact all three of the outputs. Further work is needed to improve the accuracy of representing VWC throughout a field, thus improving VRI management, and there is potential benefit in using a variable crop coefficient could to more accurate VRI management decisions from a soil water depletion model.

Die Berücksichtigung der flächenhaften bodenhydraulischen Variabilität gilt bei der Modellierung von Wasser- und Stofftransportprozessen als problematisch. Dies liegt vorrangig an ihrer Erfassung, die kosten- und zeitintensiv ist. Die vorliegende Arbeit untersucht verschiedene Messstrategien, die zur Abbildung der flächenhaften Bodenhydraulik mit wenigen, einfach zu bestimmenden und physikalisch begründeten Bodenparametern führen. Die Vorgehensweise erfolgt mit der Anwendung eines Ähnlichkeitskonzeptes, das die Böden in bodenhydraulisch ähnliche Klassen unterteilt. Innerhalb einer Klasse kann die Variabilität der Retentions- und hydraulischen Leitfähigkeitcharakteristik auf einen freien Parameter (Skalierungsparameter) reduziert werden. Die Analyse der Zusammenhänge zwischen Boden- und Skalierungsparametern führt letztendlich zu den geeigneten Parametern die eine flächenhafte Abbildung möglich machen. Diese Untersuchungen bilden die Grundlage für die weitere Entwicklung eines stochastischen Modellansatzes, der die Variabilität der Bodenhydraulik bei der Modellierung des Bodenwassertransportes im Feldmaßstab berücksichtigen kann. An Hand von drei Datensätzen unterschiedlicher Skalenausbreitung konnte dieses Konzept angewendet werden. Die Ergebnisse zeigen, dass die Beschreibung der hydraulischen Variabilität nur für die vertikale (Profil) nicht aber für die flächenhafte Ausbreitung mit einfachen Bodenparametern möglich ist. Mit einer ersten Modellanwendung konnte gezeigt werden, dass über die Variabilität der Bodenparameter Trockenrohdichte und Tongehalt auch die Variabilität der Bodenhydraulik und damit die Berechnung des Bodenfeuchteverlaufs am Standort darstellbar ist. / The consideration of the spatial variability of the unsaturated soil hydraulic characteristics still remains an unsolved problem in the modelling of the water and matter transport in the vadose zone. This can be mainly explained by the rather cumbersome measurement of this variability, which is both, time-consuming and cost-intensive. The presented thesis analyses various measurement strategies which aim at the description of the soil-hydraulic heterogeneity by a small number of proxy-parameters, which should be easily measurable and still have a soil-physical meaning. The developed approach uses a similarity concept, which groups soils into similar soil hydraulic classes. Within a class, the variability of the retention and hydraulic conductivity curves can be explained by a single parameter (scaling parameter). The analysis of the correlation between the soil parameters and the scaling parameters can eventually indicate which soil parameters can be used for describing the soil hydraulic variability in a given area. This investigation forms the basis for the further development of a stochastic model, which can integrate the soil-hydraulic variability in the modelling of the soil water transport. Three data sets, all covering different scales, were subsequently used in the application of the developed concept. The results show that depth development of the soil-hydraulic variability in a soil profile can be explained by a single soil parameter. Contrarily, the explanation of the horizontal variability of the soil-hydraulic properties was not possible with the given data sets. First model applications for a soil profile showed that including the variability of the soil parameters bulk density and clay fraction in the water transport simulations could describe the variability of the soil-hydraulic variability and thus, the dynamics of the soil water content at the investigated profile.