A concern with organic farming is for the depletion of soil phosphorus. The objectives of this study were to determine which organic management systems deplete soil phosphorus and whether arbuscular mycorrhizal fungi (AMF) could assist crops in taking up phosphorus in these systems. The research site was a 14 year-old study at Glenlea, Manitoba, having 3 different 4-year rotations under organic and conventional management: forage-grain ± manure-compost, grain-only, and a restored tall grass prairie. The modified Hedley procedure revealed organic systems to have lower concentrations of labile phosphorus than conventional but recalcitrant fractions did not differ (P < 0.05). Nitrogen was limiting in the organic grain-only rotation; phosphorus in the organic forage-grain. Mycorrhizal colonization as arbuscules was higher in organic than conventional systems (P < 0.05). To prevent phosphorus limitation, we suggest high-export organic rotations be balanced with sufficient rates of manure-compost and AMF maintained to help with phosphorus absorption. / May 2007

A concern with organic farming is for the depletion of soil phosphorus. The objectives of this study were to determine which organic management systems deplete soil phosphorus and whether arbuscular mycorrhizal fungi (AMF) could assist crops in taking up phosphorus in these systems. The research site was a 14 year-old study at Glenlea, Manitoba, having 3 different 4-year rotations under organic and conventional management: forage-grain ± manure-compost, grain-only, and a restored tall grass prairie. The modified Hedley procedure revealed organic systems to have lower concentrations of labile phosphorus than conventional but recalcitrant fractions did not differ (P < 0.05). Nitrogen was limiting in the organic grain-only rotation; phosphorus in the organic forage-grain. Mycorrhizal colonization as arbuscules was higher in organic than conventional systems (P < 0.05). To prevent phosphorus limitation, we suggest high-export organic rotations be balanced with sufficient rates of manure-compost and AMF maintained to help with phosphorus absorption.

A concern with organic farming is for the depletion of soil phosphorus. The objectives of this study were to determine which organic management systems deplete soil phosphorus and whether arbuscular mycorrhizal fungi (AMF) could assist crops in taking up phosphorus in these systems. The research site was a 14 year-old study at Glenlea, Manitoba, having 3 different 4-year rotations under organic and conventional management: forage-grain ± manure-compost, grain-only, and a restored tall grass prairie. The modified Hedley procedure revealed organic systems to have lower concentrations of labile phosphorus than conventional but recalcitrant fractions did not differ (P < 0.05). Nitrogen was limiting in the organic grain-only rotation; phosphorus in the organic forage-grain. Mycorrhizal colonization as arbuscules was higher in organic than conventional systems (P < 0.05). To prevent phosphorus limitation, we suggest high-export organic rotations be balanced with sufficient rates of manure-compost and AMF maintained to help with phosphorus absorption.

O aproveitamento de subprodutos da indústria sucroenergética como fonte de nutrientes para a lavoura tem-se tornado cada vez mais importante na cadeia de produção da cana-de-açúcar. Esses materiais são ricos em nutrientes, sendo ambiental e economicamente uma alternativa sustentável com vistas à ciclagem biogeoquímica. Diante disso, tais podem ser utilizados \"in natura\" ou receber tratamento, por exemplo, compostagem, que os transforma em organominerais quando da adição de fontes minerais, como o concentrado apatítico, a fim de melhorar a sua qualidade como fertilizante. Os objetivos deste estudo foram caracterizar os atributos químicos de um fertilizante organomineral, obtido por processo de compostagem com a co-utilização de bactérias solubilizadoras de fósforo, e avaliar a eficiência do mesmo na adubação em experimento conduzido em casa de vegetação. A compostagem foi conduzida em leiras no pátio da Usina São José da Estiva, localizada no município de Novo Horizonte-SP. Foram utilizados os subprodutos torta de filtro e cinza de caldeira, enriquecidos com concentrado apatítico de Araxá e esterco de poedeira. A combinação dos subprodutos propostos resultou na formação de quatro composições, distribuídas em 24 leiras de compostagem nas quais em metade delas foi adicionada uma mistura composta por bactérias dos gêneros Pseudomonas e Bacillus, com a finalidade de verificar a possibilidade de solubilização do concentrado apatítico. As leiras de compostagem foram conduzidas por 60 dias, sendo realizadas amostragens quinzenais. Foram realizadas análises químicas e físicas para caracterização dos subprodutos bem como de cada composição das leiras de compostagem. Complementarmente, foram realizadas as análises de fracionamento para identificar frações inorgânicas e orgânicas de fósforo nas composições das leiras de compostagem. A sequência de extratores utilizados foi: H2O ultrapura, NaHCO3 0,5 mol L-1, NaOH 0,1 mol L-1, HCl 1 mol L-1, NaOH 0,5 mol L-1 e MgCl2+H2SO4+H2O2 (para a digestão do resíduo). O cultivo do arroz foi conduzido em casa de vegetação, para avaliar a disponibilidade de fósforo oriundo das composições das leiras de compostagem. Os teores de macro e micronutrientes, além dos elementos benéficos e tóxicos, foram influenciados pelo período de compostagem e pela matéria-prima utilizada nas composições das leiras. As formas de fósforo presentes em todas as composições das leiras de compostagem corresponderam, principalmente, à fração de P moderadamente lábil. A adição de inoculantes à leira de compostagem promoveu solubilização do concentrado apatítico, sendo esse P incorporado nas frações orgânicas do P-lábil (P em NaHCO3 0,5 mol L-1) e do P-moderadamente lábil (P em NaOH 0,1 mol L-1). Em casa de vegetação, para o solo argiloso, o efeito do inoculante nas composições proporcionou maior teor de P acumulado pela parte aérea do arroz, provavelmente ocasionadas pela presença de formas de P com menor afinidade à fixação pelo solo. / The use of sugarcane industry waste as a source of nutrients for the crop has become increasingly important in the chain of sugarcane production. These byproducts are rich in nutrients and their use is an economical and environmentally sustainable option for waste recycling. In addition, they can be used \"fresh\" or undergo treatment such as composting. This process, when addition apatite concentrate, can transform these organic wastes into a highquality organo-mineral fertilizer. This study\'s aim was to characterize the chemical properties of an organic-fertilizer, obtained by composting process with the use of bacteria phosphate solubilizers, and to evaluate its fertilization efficiency in experiment conducted in greenhouse. Therefore, an experiment was conducted at sugarcane mill São José da Estiva composting field, located in Novo Horizonte-SP, Brazil. In the composting process, filter cake waste and boiler ash was enriched with Araxa apatite concentrate and hen manure. The combining proposed were forming four compositions distributed in 24 piles of compost. In half of the piles, a Pseudomonas and Bacillus bacteria mixture was added in order to enhance the possibility of apatite concentrate solubilization. The compost windrows ware conducted for 60 days and biweekly sampling was performed in each windrow. The chemical and physical analysis for characterization of byproducts were performed and each windrow composting composition. In addition, complementary fractionation analyzes of each sample was performed in order to identify the inorganic and organic phosphorus fractions. The sequence extraction was: ultrapure H2O, NaHCO3 0.5 mol L-1, NaOH 0.1 mol L-1, HCl 1 mol L-1, NaOH 0.5 mol L-1 and MgCl2 + H2SO4 + H2O2 for digestion residue. In order to evaluate the solubilization and availability of phosphorus from the windrow composting compositions, a greenhouse experiment with rice crop was designed. It was found that composting period and the material type influenced the nutrient and the toxic element content in all windrow composting compositions. Forms of phosphorus present in all windrow composting compositions and quantified by the fractionation mainly corresponded to the fraction of moderately labile. The inoculant addition at windrow composting promoted the solubilization of apatite concentrate and this P was incorporated in the organic fractions of labile P (NaHCO3 in 0.5 mol L-1) and moderately labile P (NaOH 0.1 mol L-1). Moreover, the bacterial inoculant increased P uptake by rice in clay soil, probably due to the formation of P forms with lower tendency of fixation in the soil.

O aproveitamento de subprodutos da indústria sucroenergética como fonte de nutrientes para a lavoura tem-se tornado cada vez mais importante na cadeia de produção da cana-de-açúcar. Esses materiais são ricos em nutrientes, sendo ambiental e economicamente uma alternativa sustentável com vistas à ciclagem biogeoquímica. Diante disso, tais podem ser utilizados \"in natura\" ou receber tratamento, por exemplo, compostagem, que os transforma em organominerais quando da adição de fontes minerais, como o concentrado apatítico, a fim de melhorar a sua qualidade como fertilizante. Os objetivos deste estudo foram caracterizar os atributos químicos de um fertilizante organomineral, obtido por processo de compostagem com a co-utilização de bactérias solubilizadoras de fósforo, e avaliar a eficiência do mesmo na adubação em experimento conduzido em casa de vegetação. A compostagem foi conduzida em leiras no pátio da Usina São José da Estiva, localizada no município de Novo Horizonte-SP. Foram utilizados os subprodutos torta de filtro e cinza de caldeira, enriquecidos com concentrado apatítico de Araxá e esterco de poedeira. A combinação dos subprodutos propostos resultou na formação de quatro composições, distribuídas em 24 leiras de compostagem nas quais em metade delas foi adicionada uma mistura composta por bactérias dos gêneros Pseudomonas e Bacillus, com a finalidade de verificar a possibilidade de solubilização do concentrado apatítico. As leiras de compostagem foram conduzidas por 60 dias, sendo realizadas amostragens quinzenais. Foram realizadas análises químicas e físicas para caracterização dos subprodutos bem como de cada composição das leiras de compostagem. Complementarmente, foram realizadas as análises de fracionamento para identificar frações inorgânicas e orgânicas de fósforo nas composições das leiras de compostagem. A sequência de extratores utilizados foi: H2O ultrapura, NaHCO3 0,5 mol L-1, NaOH 0,1 mol L-1, HCl 1 mol L-1, NaOH 0,5 mol L-1 e MgCl2+H2SO4+H2O2 (para a digestão do resíduo). O cultivo do arroz foi conduzido em casa de vegetação, para avaliar a disponibilidade de fósforo oriundo das composições das leiras de compostagem. Os teores de macro e micronutrientes, além dos elementos benéficos e tóxicos, foram influenciados pelo período de compostagem e pela matéria-prima utilizada nas composições das leiras. As formas de fósforo presentes em todas as composições das leiras de compostagem corresponderam, principalmente, à fração de P moderadamente lábil. A adição de inoculantes à leira de compostagem promoveu solubilização do concentrado apatítico, sendo esse P incorporado nas frações orgânicas do P-lábil (P em NaHCO3 0,5 mol L-1) e do P-moderadamente lábil (P em NaOH 0,1 mol L-1). Em casa de vegetação, para o solo argiloso, o efeito do inoculante nas composições proporcionou maior teor de P acumulado pela parte aérea do arroz, provavelmente ocasionadas pela presença de formas de P com menor afinidade à fixação pelo solo. / The use of sugarcane industry waste as a source of nutrients for the crop has become increasingly important in the chain of sugarcane production. These byproducts are rich in nutrients and their use is an economical and environmentally sustainable option for waste recycling. In addition, they can be used \"fresh\" or undergo treatment such as composting. This process, when addition apatite concentrate, can transform these organic wastes into a highquality organo-mineral fertilizer. This study\'s aim was to characterize the chemical properties of an organic-fertilizer, obtained by composting process with the use of bacteria phosphate solubilizers, and to evaluate its fertilization efficiency in experiment conducted in greenhouse. Therefore, an experiment was conducted at sugarcane mill São José da Estiva composting field, located in Novo Horizonte-SP, Brazil. In the composting process, filter cake waste and boiler ash was enriched with Araxa apatite concentrate and hen manure. The combining proposed were forming four compositions distributed in 24 piles of compost. In half of the piles, a Pseudomonas and Bacillus bacteria mixture was added in order to enhance the possibility of apatite concentrate solubilization. The compost windrows ware conducted for 60 days and biweekly sampling was performed in each windrow. The chemical and physical analysis for characterization of byproducts were performed and each windrow composting composition. In addition, complementary fractionation analyzes of each sample was performed in order to identify the inorganic and organic phosphorus fractions. The sequence extraction was: ultrapure H2O, NaHCO3 0.5 mol L-1, NaOH 0.1 mol L-1, HCl 1 mol L-1, NaOH 0.5 mol L-1 and MgCl2 + H2SO4 + H2O2 for digestion residue. In order to evaluate the solubilization and availability of phosphorus from the windrow composting compositions, a greenhouse experiment with rice crop was designed. It was found that composting period and the material type influenced the nutrient and the toxic element content in all windrow composting compositions. Forms of phosphorus present in all windrow composting compositions and quantified by the fractionation mainly corresponded to the fraction of moderately labile. The inoculant addition at windrow composting promoted the solubilization of apatite concentrate and this P was incorporated in the organic fractions of labile P (NaHCO3 in 0.5 mol L-1) and moderately labile P (NaOH 0.1 mol L-1). Moreover, the bacterial inoculant increased P uptake by rice in clay soil, probably due to the formation of P forms with lower tendency of fixation in the soil.

Orientador: Juliano Carlos Calonego / Resumo: O fósforo (P) é um dos nutrientes que mais limitam a produção agrícola em solos tropicais. No solo ele é encontrado sob formas inorgânicas (Pi) e orgânicas (Po), com diferentes labilidades. Formas menos lábeis de Pi e Po poderão contribuir para nutrição das plantas, mas para isso precisam ser solubilizadas e mineralizados, respectivamente. Plantas de cobertura contribuem para solubilização de compostos menos lábeis aumentando teor de P lábil no solo. Contudo, nem sempre a essa solubilização implica em reciclagem e absorção pelas plantas, levantando as principais hipóteses: a) as raízes das plantas de cobertura liberam ácidos orgânicos capazes de complexar P via ponte metálica, reduzindo o movimento do P no solo; b) as plantas de cobertura absorvem o P do solo e, após processo de decomposição, o devolvem, em sua maior parte, na forma de ácido fítico, não disponível para as plantas; c) a adubação nitrogenada pode influenciar na mineralização de compostos orgânicos do solo, aumentando a disponibilidade de P oriundo do Po. Assim, foram conduzidos dois experimentos: o primeiro com o objetivo de avaliar o efeito das plantas de cobertura (Urochloa ruziziensis, Urochloa brizantha e Panicum maximum) e das doses de nitrogênio (N) (70, 140 e 210 kg ha-1 ) na dinâmica de P do solo, bem como a sua relação com o acúmulo de P e a produtividade de plantas de milho em duas safras consecutivas; e o segundo objetivando avaliar a mobilidade do P em solo cultivado previamente com plantas de cober... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Phosphorus (P) is an essential plant nutrient and is one of the most critical elements influencing crop production throughout the world. Phosphorus deficiency is widespread in most soils of northern Ghana, and ferruginous nodules contained in some soils in the region accentuate the deficiency problem because they act as P sinks. This research focuses on P fertility status of soils in landscapes common to northern Ghana. Three sites were selected for the study and were referred to as sites 1, 2 and 3. Soils in a catenary sequence from site 1 were sampled for detailed P distributions in profiles, and surface soils from the upper, mid and lower slope positions of the other landscapes (sites 2 and 3) were used. The nature of P in the soil fines and ferruginous nodules was investigated using a modified Hedley fractionation procedure. The objective was to quantify the labile and non-labile inorganic P (Pi) and organic P (Po) in relation to pedogenic weathering processes at different slope positions at site 1. A secondary objective was to assess the P distribution in the landscapes at sites 2 and 3. The largest P fraction in both soil fines and nodules at each site was resistant non-labile P forms. Primary P (Ca-P) decreased with depth in the profile at the upper slope position but it occurred in greater quantities in C horizons of the lower slope soils. Phosphorus sorption capacity of the soil fines and nodules was determined to predict the behaviour of P fertilizers in the soils. Phosphorus sorption by the soil fines increased to a maximum in the B horizon of each profile and a t-test showed that P sorption was similar in profiles at each slope position. The P sorption capacities of uncrushed ferruginous nodules varied according to their sizes. The small nodules were more reactive and sorbed more P than the larger sizes. Fractionation of P from the nonfertilized and fertilized soils at the end of cropping and anion exchange resin (AER) extraction, revealed that there had been redistribution of P into different fractions. A comparison of P fractions of the nonfertilized soils after the AER extraction with those of the native soil P showed decreases in some native labile and non-labile P fractions. This suggested that these P fractions could be available for plant uptake. Both 50% PAPR and SSP fertilizations increased the labile Pi and NaOH extractable Pi levels in the soils. (Abstract shortened by UMI.)

Intensive forest management techniques such as whole-tree harvesting and use of herbicides to control weeds can have an effect on nutrient cycling and nutrient pool sizes in the mineral soil. This study was conducted to measure differences in soil carbon (C), nutrient pools, or phosphorus (P) fractions associated with harvest-intensity (bole-only vs. whole-tree harvest) and weed-control treatments (initial weed control vs. five years of annual weed control) after ten years. Soil C, nitrogen (N), and P, and exchangeable calcium (Ca), potassium (K), magnesium (Mg), and Hedley P fractions were measured prior to treatment establishment and after ten years in two Douglas-fir (Pseudotsuga menziesii) plantations in the Pacific Northwest. We observed increases in most nutrient concentrations with initial weed control compared with annual weed control at Matlock, with opposite trends at Molalla. Exchangeable Ca and Mg content showed responses to weed control treatments. Harvesting treatments had no significant effects on soil C and nutrient pools at either site. Total P and many of the Hedley P fractions decreased over time, but these effects were ameliorated with the less-intensive initial-weed-control-only treatment at Matlock and the more-intensive annual-weed-control at Molalla. Ten-year responses suggest that harvesting intensity has not impacted potential for maintaining soil C and nutrient pools, with the exception of P, for long-term productivity. Knowledge of the on-site vegetative communities and their role in nutrient cycling is required to anticipate what effect weed control might have on nutrient pools through ensuing stand development. / Master of Science

[pt] O objetivo da dissertação é avaliar a contribuição e o desenvolvimento da Escola Inglesa de Relações Internacionais. Para tanto, opta-se pela análise histórica, priorizando-se uma abordagem cronológica. Nesse sentido, analisa-se, inicialmente, a contribuição de dois de seus principais teóricos: Martin Wight e Hedley Bull, que estabeleceram os eixos teóricos e conceituais constitutivos da Escola. Na segunda parte, considera-se o debate sobre a identidade e a validade da contribuição da Escola nos anos 1980. Na última parte, apresenta-se uma avaliação da Escola Inglesa nos anos 1990. Introduz-se, então, a bifurcação entre uma vertente crítica e outra clássica e a inovação trazida por uma nova geração de teóricos. Por fim, procura- se apresentar, de forma crítica, o debate travado dentro da Escola sobre o conflito do Kosovo. / [en] The aim of this dissertation is to evaluate the contribution and the development of the English School of International Relations. In order to achieve this, the analytical axis will be historic, emphasising a chronological approach. In this sense, it was accessed the contribution of two of its leading theorists: Martin Wight and Hedley Bull, that together established the mains theoretical and conceptual axis constitutive of the school. In the second part, the debate about the identity and the validity of the contribution of the school in the 1980s was analysed. In the last part, it is offered an evaluation of the English School in the 1990s. Its bifurcation into two approaches, a critical and a classical one; and the theoretical innovation brought by a new generation of theorists, will be introduced. Latter on, it will be offered an critical analysis of the debate that took place in the English School after the conflict at Kosovo.

Phosphorus is the main limiting nutrient for plant growth in large areas of the world and the availability of phosphorus to plants and microbes can be strongly affected by soil properties. Even though the phosphorus cycle has been studied extensively, much remains unknown about the key processes governing phosphorus availability in different environments. In this thesis the complex dynamics of soil phosphorus and its availability were studied by relating various phosphorus fractions and soil characteristics to microbial respiration kinetics. The soils used represent a range of aluminium, iron, carbon and total phosphorus content, and were located in four different biomes: subtropical forest, warm temperate forest, boreal forest and tundra. The results showed that NaOH extractable phosphorus, a fraction previously considered to be available to plants only over long time scales, can be accessed by microbes in days or weeks. Microbial phosphorus availability was not related to aluminium or iron content in any of the studied systems, not even in highly weathered soils with high aluminium and iron content. This is in contrast with other studies of soils with high sorption capacity and shows the variability of factors that govern phosphorus availability in different environments. In the boreal forest chronosequence, no difference could be seen with age in total phosphorus content or concentrations of occluded phosphorus forms. However, there were lower concentrations of labile phosphorus forms in older systems, which were correlated with a decrease in microbial respiration. This was most likely related to organic matter quality in the system, and not to geochemical factors. Phosphorus availability was linked to differences in topography (water regime) and vegetation in the tundra ecosystems. The results suggest that the availability of phosphorus, both for microbes and plants, was lower on the meadow vegetation sites compared to the two types of heath vegetation. Many factors are important for phosphorus availability in soils, but these results suggest that microbes can access less available phosphorus if not restricted by carbon, and this may be important in regard to forest management practices as well as effects of environmental change.