The soils used by the East Coast Organic Producers Trust (ECOPT; the grower group that this study is targeted towards) have exceptionally low soil Olsen P concentrations (ca. 6 mg/L). These and other limitations (e.g. poor weed and pest and disease control) result in many ECOPT growers being unable to produce economic yields on anything other than small scale gardens. Fertilisers and manures are seldom used by these growers, which exacerbates the problem. Thus, the object of this research was to provide information to ECOPT on which fertilisers and application strategies would provide the best returns on their phosphorus (P) fertiliser investment. The experimental work was carried out in two parts. A laboratory study tested a range of phosphate rock (PR) based fertilisers and application rates; Ben Guerir reactive phosphate rock (RPR; 67, 133, 267, 533 and 1,333 mg P/kg soil), BioPhos and BioSuper (267 and 1,333 mg P/kg soil) and a no fertiliser Control. Soil fertiliser mixtures were incubated for 155 days and periodic measurements of PR dissolution, soil pH and Bic-P (analogous to Olsen P but expressed in µg/g) were undertaken. The field study used fewer application rates and two application methods; banded and broadcast. Broadcast plots were applied at 678 mg P/kg soil (488 kg P/ha); banded RPR was applied at 236, 678 and 1475 mg P/kg soil (40, 115 and 250 kg P/ha respectively) and banded BioPhos and BioSuper at 678 mg P/kg soil (115 kg P/ha). A Control was also included. Fertilisers were applied in October 2004 and changes in soil pH and Bic-P were measured in the broadcast plots only over a 344 day period. Potato (Solanum tuberosum L. cv. Desiree) was the test crop. Regression analysis was used to generate exponential equations to describe the changes in Bic-P over time (∆Bic-P). Differences between fertilisers in the amount of P dissolved and pH fluxes were used to explain the differences in ∆Bic-P. BioSuper dissolved quicker and generated greater ∆Bic-P than RPR and BioPhos, which were similar. Higher application rates produced greater increases in Bic-P than lower rates but decreased the % of P applied that dissolved. The increase in Bic-P over time from fertiliser application was much slower in the field compared with the laboratory. This was put down to differences in experimental conditions; mainly soil pH and soil aggregate surface area. Potato tuber yield (mean = 35 t/ha) did not respond to any of the fertiliser treatments despite a significant increase in P concentration of the shoots mid-way through the season in all broadcast treatments (shoot P concentration was not analysed in the banded plots). Water and N availability were the main limiting factors in this season as the crop was not irrigated and soil N supply was insufficient to produce a full canopy. Phosphorus response curves generated using the fertiliser response model PARJIB (Reid, 2002), and an economic analysis, indicated that for RPR and BioPhos the optimum economic application rate was 200 kg P/ha and for BioSuper it was 100 kg P/ha (applied every third and second year respectively).

Os solos brasileiros apresentam baixa disponibilidade de fósforo (P). Devido à natureza mineralógica desses solos, a adubação é uma tarefa difícil, em função dos processos de adsorção específica e precipitação, que causam baixa recuperação do P aplicado. Os fertilizantes totalmente acidulados (FTA), com praticamente todo P solúvel em água, são as fontes mais utilizadas no Brasil. Porém, a utilização dessas fontes, pode não ser o mais indicado para esses solos. Teoricamente, o fertilizante fosfatado ideal possibilitaria suprir a demanda inicial da planta, apresentando ainda liberação lenta durante o ciclo da cultura, resultando em cinética de liberação do P mais ajustada a demanda das culturas. Com base nessa premissa, objetivou-se com esse trabalho avaliar a eficiência de fertilizantes fosfatados produzidos por meio da mistura no mesmo grânulo de FTA, fosfato natural reativo de Bayóvar (FN) e enxofre elementar (S0). Os fertilizantes foram avaliados em experimentos de incubação, casa de vegetação e campo. O estudo de incubação foi conduzido com objetivo de avaliar a difusão, disponibilidade e produtos de reação do P e S dos fertilizantes: fosfato monoamônico (MAP), superfosfato triplo (SFT) e MES (MicroEssentials®); e os fertilizantes produzidos: MAP+FN, MAP+FN+S0[2:1], MAP+FN+S0[1:1], SFT+FN e SFT+FN+S0[2:1], obtidos por meio da granulação dos FTA com o FN, na relação 1:1, com base no P total das fontes, com ou sem adição de S0 na composição. Os fertilizantes produzidos com MAP proporcionaram maiores difusões e disponibilidade do P, do que os fertilizantes com SFT. O S0 melhorou a difusão e disponibilidade do P dos fertilizantes produzidos, principalmente nos fertilizantes contendo MAP. Dois experimentos foram conduzidos em casa de vegetação, destacando-se como objetivos principais: estudar a proporção entre os FTA o FN e a presença do S0 na mistura; quantificar o efeito do S0 no aumento da absorção de P do FN, utilizando o 32P e avaliar os fertilizantes com S0 na composição em fornecer S para a cultura do milho, comparando-os com fertilizantes comerciais. Nos fertilizantes com 50% de MAP ou SFT, o aumento na absorção de P dos fertilizantes em função da adição do S0 foi de 26 e 18%, respectivamente. Os fertilizantes com S0 na composição foram menos eficientes no fornecimento de S para o milho do que o S0 aplicado em pó, mas, foram mais eficientes do que o fertilizante contendo S0 pastilhado com bentonita. O estudo de campo foi conduzido com a cultura da soja em um Latossolo Vermelho na região do Cerrado, município de Itiquira-MT. Os fertilizantes avaliados foram: MAP, FN, MAP+FN, MAP+FN+S0[2:1] e MAP+FN+S0[1:1], aplicados a lanço e localizado. Os fertilizantes MAP+FN[2:1] e MAP+FN[1:1] obtiveram eficiência agronômica superior à do MAP+FN e semelhantes à do MAP. Os fertilizantes produzidos com S0 na composição apresentam potencial para serem utilizados na agricultura, podendo ser fontes alternativas aos FTA, ainda com fornecimento de S. Este foi provavelmente o primeiro estudo de campo utilizando essa associação. Outros estudos, em outras condições de solo e clima, devem ser realizados para confirmar a viabilidade do uso dessas fontes. / Brazilian soils has low phosphorus (P) availability. Due to the mineralogical composition of these soils, fertilization is a challenge, because of the specific adsorption and precipitation processes, causing low P recovery from fertilizers. Fully acidulated P fertilizers (FAP), practically with all P soluble in water, are the most used sources in Brazil. However, they may not be the most appropriate sources for these soils. Theoretically, the ideal phosphate fertilizer would be the one which supplies the initial plant demand as well as releases slowly P during the crop cycle, allowing better synchronization between the plant demand and dissolution of P source. Based on this premise, the aim of this study was to evaluate the efficiency of phosphate fertilizers produced by mixture of FAP, Bayóvar phosphate rock (PR) and elemental sulfur (S0) in the same granule. The fertilizers were evaluated in incubation, greenhouse and field trials. The incubation study was carried out to evaluate the diffusion, availability and reaction products of P and S from the fertilizers: monoammonium phosphate (MAP), triple superphosphate (TSP) and MES (MicroEssentials®); and the produced fertilizers: MAP+PR, MAP+PR+S0[2:1], MAP+PR+S0[1:1], TSP+PR and TSP+PR+S0[2:1], obtained by granulation of FAP with PR in the ratio 1:1, based on total P content, with or without S0 in the composition. Fertilizers with MAP in the composition resulted in better P diffusion and availability than the fertilizers with TSP. The S0 improved the P diffusion and availability mainly from fertilizers produced with MAP. Two experiments were carried out in greenhouse, with the objectives to: study the FAP and PR ratio and S0 presence in the mixture; quantify the S0 effect for increasing the P uptake from PR, using 32P; and evaluate the fertilizers with S0 in the composition to provide sulfur (S) for maize, comparing them with commercial sources. The S0 presence in the granule improved the P uptake on 26 and 18% from the fertilizers produced with 50 % from MAP or TSP, respectively. The fertilizers with S0 in the composition were less efficient than powdered S0 providing S to maize, but they were better than commercial fertilizer with bentonite+S0. The field trial was carried out with soybean in an Oxisol in Cerrado region, Itiquira-MT. The fertilizers evaluated were: MAP, PR, MAP+PR, MAP+PR+S0[2:1] and MAP+PR+S0[1:1] applied in band or broadcast. The fertilizers MAP+PR+S0[2:1] and MAP+PR+S0[1:1] were better than MAP+PR and similar to MAP on soybean yield and agronomic efficiency. Fertilizers produced by MAP+PR and S0 in the same granule can be potential sources to be used in agriculture, could be alternative sources for FAP, moreover can supply S to crops. Probably this was the first study using the abovementioned association. Other studies in others soils and weather conditions should be carried out to confirm the potential use of these sources.

Made available in DSpace on 2014-06-11T19:27:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12-20Bitstream added on 2014-06-13T18:31:16Z : No. of bitstreams: 1 lemos_gc_me_araca.pdf: 160789 bytes, checksum: 0de461ffc42d8847ad0ddb66ab8b1f25 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foi avaliado o desempenho produtivo e a interferência do flúor em bovinos Nelore suplementados com fontes alternativas de fósforo. As fontes de fósforo e as relações P:F foram distribuídas nos seguintes tratamentos: controle (CONTNEG), fosfato bicálcico 120:1 (FB-120), 30:1 (FB-30) e 10:1 (FB-10), monobicálcico 60:1 (MBC-60), superfosfato triplo 30:1 (SFT-30) e rocha de Cajati 10:1 (ROCHA-10). Foram utilizados 49 novilhos, desmamados, com nove meses de idade, castrados e com 230 kg de peso médio, distribuídos em sete piquetes, com água e mistura mineral completa ad libitum, exceto fósforo. A dieta padrão foi calculada para um ganho de peso aproximado de 0,500 kg/dia. Os animais do tratamento SFT-30, atingiram o peso de 520 kg, aproximadamente cinco meses antes que os do tratamento ROCHA-10, devido à solubilidade do P nas fontes. As análises de fósforo no osso mostraram diferença estatística apenas entre o tratamento CONTNEG e os tratamentos com fosfato bicálcico. As análises de flúor no osso se mostraram intimamente associados à quantidade de flúor disponível nas fontes testes. Pode-se concluir que as diferentes fontes de fósforo utilizadas interferiram nos resultados de desempenho dos animais. / The productive performance and the interference of fluorine in supplemented Nelore bovines with alternative sources of phosphorus were evaluated. The sources of phosphorus and relations P:F had been distributed in the following treatments: control (CONTNEG), dicalcium phospate 120:1 (FB-120), 30:1 (FB-30) and 10:1 (FB-10), monodicalcium 60:1 (MBC-60), triple superphosphate 30:1 (SFT-30) and Cajati Rock 10:1 (ROCHA-10). Forty nine castrated steers with nine months of age averaging 230 kg distributed in seven pens, with water available and a complete mineral mixture, except phosphorus. The ration was formulated for a weight gain of 0,500 kg/day. Animals of SFT-30 treatment had reached 520 kg approximately five months before ROCHA-10 treatment, due to the P solubility in the sources. The analyses of phosphorus in the bone had shown statistical differences only between treatment CONTNEG and the treatments with dicalcium phosphate. Bone fluorine analyses were highly associated to fluorine quantity in the phosphorous sources evaluated. It can be concluded that the different phosphorus sources used had influenced animal performance.

Made available in DSpace on 2014-08-20T13:25:40Z (GMT). No. of bitstreams: 1 Dissertacao_Eduardo_Flores_Cardoso.pdf: 507508 bytes, checksum: 623adc3460ce91360c881c18dfd82c71 (MD5) Previous issue date: 2007-09-19 / In irrigated rice crop, the lowland soils can supply the plants with different phosphorus quantities due to the source material and phenomena that occur in the different oxidation and reduction cycles of these soils. An important soil factor that regulates the phosphorus availability for the plants is the maximum phosphorus adsorption capacity. Therefore, the objectives of this work were to evaluate the response of the irrigated rice fertilized with two sources of phosphorus in lowland soils with different phosphorus adsorption capacity and to evaluate the prediction capacity of the methods Mehlich-1 and Ionic Exchange Resin in Sphere regarding the phosphorus availability for the irrigated rice in these soils. The soil samples were taken from the top 20 cm of three lowland soils with different maximum phosphorus adsorption capacity (MPAC): Typic Albaqualf, low MPAC; Vertic Albaqualf, average MPAC and Typic Endoaqualf, high MPAC. The experimental units were constituted of plastic buckets containing 6 kg of dry soil, where two phosphorus sources (phosphate rock and triple superphosphate) and six levels of phosphorus: 0, 10, 20, 40, 80, 160 mg kg-1 P were applied, with three replications, totaling 128 experimental units. The pots were positioned in the greenhouse in a completely randomized experimental design. The rice was cultivated for 45 days and the dry matter weight was quantified through aerial part of the plants. The phosphorus content was analyzed by extractor Mehlich-1 and Resin methods in the soil, in the soil solution and in the plant. The obtained results showed that: Typic Albaqualf respond with increased dry matter weight of rice plant aerial part up to the level of 10 mg kg-1 of phosphorus applied in the soil, while in the Typic Endoaqualf the response to the applied phosphorus was up to the level of 80 mg kg-1. Vertic Albaqualf did not respond to phosphorus; soil with higher maximum phosphorus adsorption capacity (MPAC), Typic Endoaqualf, required higher phosphorus quantity (phosphate rock and triple superphosphate) to reach maximum dry matter weight of rice plant aerial part up; the triple superphosphate presented greater solubility than phosphate rock Daoui during the flood of the lowland soils in this experiment; the extractor Mehlich-1 and the Ion Exchange Resin method were equivalent in the prediction capacity of the phosphorus availability for the irrigated rice in the lowland soils in this experiment. / Na cultura do arroz irrigado, os solos de várzea podem suprir as plantas com diferentes quantidades de fósforo devido ao material de origem e aos fenômenos que ocorrem nos diferentes ciclos de oxidação e redução desses solos. Um fator importante do solo que regula a disponibilidade do fósforo para as plantas é a capacidade de adsorção de fósforo. Nesse sentido, o objetivo deste trabalho foi avaliar a resposta do arroz irrigado adubado com duas fontes de fósforo em solos de várzea com diferentes capacidades de adsorção de fósforo e avaliar a capacidade de predição dos métodos Mehlich-1 e Resina Trocadora de Íons em esfera na disponibilidade de fósforo para o arroz irrigado. Foram coletadas três amostras da camada superficial (0-20 cm) de solos de várzea com diferentes capacidades máximas de adsorção de fósforo (CMAP): Planossolo Háplico (Pelotas), baixa CMAP; Planossolo Háplico (Bagé), média CMAP e Gleissolo Háplico (Banhado), alta CMAP. As unidades experimentais constituíram-se de vasos plásticos contendo 6 kg de solo seco, onde foram aplicadas duas fontes de fósforo (fosfato natural e superfosfato triplo) e seis níveis de fósforo: 0, 10, 20, 40, 80, 160 mg kg-1 P, com três repetições, totalizando cento e oito unidades experimentais. Os vasos ficaram dispostos na casa de vegetação em um delineamento inteiramente casualizado. Cultivou-se o arroz durante quarenta e cinco dias e colheu-se a parte aérea das plantas para quantificar o peso de matéria seca. Foram analisados os teores de fósforo: no solo pelos extratores Mehlich-1 e Resina em esferas; na solução do solo e no tecido vegetal. Os resultados obtidos mostraram que: o Planossolo Háplico (Pelotas) respondeu com aumento de peso de matéria seca da parte aérea do arroz até a dose de 10 mg kg-1 de fósforo aplicado no solo, enquanto que no Gleissolo Háplico (Banhado) a resposta ao fósforo aplicado foi até a dose de 80 mg kg-1. Já no Planossolo Háplico (Bagé) não houve resposta ao fósforo; o solo com maior capacidade máxima de adsorção de fósforo (CMAP), Gleissolo Háplico (Banhado), necessitou maior quantidade de fósforo aplicado na forma de superfosfato triplo e fosfato natural para atingir a máxima produção de matéria seca da parte aérea; o superfosfato triplo apresentou maior solubilização do que o fosfato natural Daoui durante o alagamento dos solos de várzea utilizados neste experimento; o extrator Mehlich-1 e o método da Resina Trocadora de Íons em esfera equivaleram-se na capacidade de predição da disponibilidade de fósforo para o arroz irrigado nos solos de várzea utilizados neste experimento.

An injection technique, in which undisturbed soil cores are labelled with ³²P to study dissolution of phosphate fertilisers in the soil, was evaluated in field and glasshouse trials. When ³²P was injected between 0-150 mm depths of the undisturbed soil columns and fertilisers applied at the surface, the amounts of fertiliser P dissolved, as measured by the increases in the exchangeable P pools, were overestimated. Three possible reasons were suggested: (i) the interaction between surface-applied fertiliser, ³²P injected through the whole soil column, and the vertical decline in root density, (ii) the decline of specific activity in the exchangeable P pool due to losses of ³²P to nonexchangeable P pools and continuous addition of P from fertiliser dissolution, and (iii) non-uniform distribution of ³²P vis-a-vis ³¹P phosphate. The injection technique may be employed to assess the effectiveness of phosphate fertilisers by introducing a concept, the fertiliser equivalent (FE). The FE is a measure of the amounts of soil exchangeable P that the fertilisers are equivalent to in supplying P to plants, when applied at the specific location. Soluble single superphosphate (SSP) applied at the surface of undisturbed grassland soil cores (Tekapo fine sandy loam), was much more effective than surface-applied unground North Carolina phosphate rock (NCPR) and 30% acidulated NCPR with phosphoric acid (NCPAPR) within the 56 day period of plant growth. An isotopic dilution method, based on tracer kinetic theory, was developed to study the rates of dissolution (F in) and retention (F out) of phosphate fertilisers in the soil in growth chamber experiments. The estimation of F in and F out required labelling of the soils with carrier-free ³²P and determination of the corresponding values of the specific activities of the exchangeable P pools, SA₁ and SA₂, and the sizes of the exchangeable P pools, Q₁ and Q₂, at times t₁ and t₂. Most of the phosphate in the monocalcium phosphate (MCP) solution entered the exchangeable P pool immediately after addition to the soils (Tekapo fine sandy loam and Craigieburn silt loam), and there was little further phosphate input. With increasing periods of incubation, the phosphate was quickly transformed to less rapidly exchangeable forms. In the soils treated with ground North Carolina phosphate rock (<150 µm, NCPR) or partially acidulated (30%) NCPR with phosphoric acid (NCPAPR), the initial exchangeable P pools were not as large as those in the soils treated with MCP, but were maintained at relatively stable concentrations for extended periods, due to the continuous dissolution of PR materials and to lower rates of pretention. An increase in P-retention caused a slight rise in the rate of PR dissolution, but also a rise in the rate of P-retention by the soil. The rate of dissolution was higher at a lower application rate in relative terms, but smaller in absolute terms. The trends in the changes of plant-available P in the soils, measured by the water extractable P, Bray I P and Olsen P, correspond to those predicted by the F in and F out values. The average rates of dissolution between 1-50 and 50-111 days estimated by the F in, however, were higher than those estimated by extractions with 0.5 M NaOH followed by 1 M HCl, and with 0.5 M BaCl₂/TEA. This is partly because the Fin values reflect a plant growth effect on PR dissolution. The relative agronomic effectiveness of NCPR and NCPAPR with respect to MCP was higher after 50 and 111 days of incubation than after 1 day. The F in values were included in all the two-variable models constructed by stepwise regression to describe the relationship between plant P uptake and soil measurements. The amounts of variation in plant P uptake accounted for by the regression model was significantly improved by including F in in the model. This indicates the importance of fertiliser dissolution rates in affecting soil P supply, when phosphate fertilisers differing in solubility are applied.

Orientador: Manoel Garcia Neto / Banca: Cecílio Viega Soares Filho / Banca: Júlio César Damasceno / Resumo: Foi avaliado o desempenho produtivo e a interferência do flúor em bovinos Nelore suplementados com fontes alternativas de fósforo. As fontes de fósforo e as relações P:F foram distribuídas nos seguintes tratamentos: controle (CONTNEG), fosfato bicálcico 120:1 (FB-120), 30:1 (FB-30) e 10:1 (FB-10), monobicálcico 60:1 (MBC-60), superfosfato triplo 30:1 (SFT-30) e rocha de Cajati 10:1 (ROCHA-10). Foram utilizados 49 novilhos, desmamados, com nove meses de idade, castrados e com 230 kg de peso médio, distribuídos em sete piquetes, com água e mistura mineral completa ad libitum, exceto fósforo. A dieta padrão foi calculada para um ganho de peso aproximado de 0,500 kg/dia. Os animais do tratamento SFT-30, atingiram o peso de 520 kg, aproximadamente cinco meses antes que os do tratamento ROCHA-10, devido à solubilidade do P nas fontes. As análises de fósforo no osso mostraram diferença estatística apenas entre o tratamento CONTNEG e os tratamentos com fosfato bicálcico. As análises de flúor no osso se mostraram intimamente associados à quantidade de flúor disponível nas fontes testes. Pode-se concluir que as diferentes fontes de fósforo utilizadas interferiram nos resultados de desempenho dos animais. / Abstract: The productive performance and the interference of fluorine in supplemented Nelore bovines with alternative sources of phosphorus were evaluated. The sources of phosphorus and relations P:F had been distributed in the following treatments: control (CONTNEG), dicalcium phospate 120:1 (FB-120), 30:1 (FB-30) and 10:1 (FB-10), monodicalcium 60:1 (MBC-60), triple superphosphate 30:1 (SFT-30) and Cajati Rock 10:1 (ROCHA-10). Forty nine castrated steers with nine months of age averaging 230 kg distributed in seven pens, with water available and a complete mineral mixture, except phosphorus. The ration was formulated for a weight gain of 0,500 kg/day. Animals of SFT-30 treatment had reached 520 kg approximately five months before ROCHA-10 treatment, due to the P solubility in the sources. The analyses of phosphorus in the bone had shown statistical differences only between treatment CONTNEG and the treatments with dicalcium phosphate. Bone fluorine analyses were highly associated to fluorine quantity in the phosphorous sources evaluated. It can be concluded that the different phosphorus sources used had influenced animal performance. / Mestre