No abstract

R ESU M OObjetivou-se, com o presente trabalho, avaliar o crescimento vegetativo do girassol irrigado com diferentes lâminas de esgoto doméstico tratado e água de poço freático e adubado com diferentes doses de nitrogênio. O experimento foi conduzido no Centro de Pesquisa sobre Tratamento e Reúso de Águas Residuárias, em Aquiraz, CE. O delineamento estatístico adotado foi o de blocos ao acaso, no esquema de parcelas subsubdivididas, com quatro repetições. Nas parcelas foram avaliados os efeitos dos dois tipos de água de irrigação sobre os parâmetros de crescimento da cultura e, nas subparcelas, os efeitos das cinco lâminas de irrigação baseadas em percentuais da evaporação do tanque classe A (ECA), que corresponderam à multiplicação da ECA pelos fatores 0,25; 0,50; 0,75; 1,00 e 1,25; nas subsubparcelas determinou-se o efeito de quatro doses de adubação nitrogenada, a saber: 25, 50, 75 e 100 kg ha -1. A altura da planta, diâmetro do caule e número de folhas, aumentaram linearmente em função das lâminas de irrigação. Os valores obtidos para água de reúso sempre foram superiores aos obtidos com a água de poço. O diâmetro do capítulo aumentou de modo quadrático em função do aumento da lâmina de irrigação e das doses de adubo nitrogenado. Palavras-chave:Helianthus annuus L., esgoto tratado, gotejamento Growth of irrigated sunflower under different water sources and nitrogen fertilization A B ST R A C T The objective of the present study was to evaluate the growth of sunflower crop irrigated with different water sources (both treated wastewater and well water) and application of different rates of nitrogen fertilizer. The experiment was conducted at the Research Center of Treatment and Reuse of Sewer Water located in the municipality of Aquiraz in the State of Ceará, Brazil. The statistical design consisted of a randomized block in split-plots with four replications. In the plots, the effects of two types of irrigation water on sunflower growth parameters was evaluated and in the subplots the effects of the five irrigation levels; according to the percentage of Class A Evaporation Pan (ECA),corresponding to the multiplication of ECA by factors of 0.25, 0.50, 0.75, 1.00 and 1.25 levels were determined. In splitplots, the effects of the four rates of nitrogen (25, 50, 75 and 100 kg ha -1 ) on the same growth parameters were evaluated. The plant height, stem diameter and number of leaves increased linearly as a function of the irrigation water levels. The parameter values obtained for wastewater were consistently higher than those obtained with well water. The capitulum diameter increased in a quadratic manner as a function of the irrigation water levels and nitrogen fertilizer rates.

Com o objetivo de avaliar a interferência da relação fósforo-zinco sobre o crescimento inicial de pitaia para fornecer informações que subsidiem a definição de sistemas de produção mais adequados para a exploração desta cultura no Brasil, realizou-se o experimento, testando cinco doses de P (0; 75; 150; 225 e 300 mg dm-3) e Zn (0; 2; 4; 6 e 8 mg dm-3), sendo os níveis de cada nutriente arranjados em esquema fatorial 5x5, com quatro blocos. Para a interação significativa (p<0,05), procedeu-se ao ajuste em superfícies de resposta do tipo Y = β0 + β1(A) + β2(A)² + β3(B) + β4(B)² + β5(A).( B) + e. As estimativas das correlações fenotípicas foram obtidas considerando apenas o intervalo das doses de P e Zn que promoveram as melhores respostas do acesso de pitaia para os caracteres estudados. A aplicação de P e Zn, e a interação P x Zn afetam a disponibilidade de ambos os nutrientes no substrato, sistema radicular e parte aérea, influenciando, assim, o crescimento inicial de plantas de pitaia. Os rendimentos mais satisfatórios ocorrem quando há 60 - 75 mg de P dm-3 e 3,0 - 4,0 mg de Zn dm-3 no substrato, e 4,5 - 6,0 g kg-1 de P e 150 mg de Zn kg-1 na parte aérea. Esses níveis foram obtidos para a combinação de 150 - 225 mg dm-3 de P, com 4 - 6 mg dm-3 de Zn. Os teores de P e Zn na parte aérea e o somatório do comprimento dos cladódios (SCC) säo os caracteres explicativos que apresentam maiores efeitos diretos sobre a massa seca dos cladódios (MSC).

RESUMOA mamoneira (Ricinus communis L.), oleaginosa de relevante importância econômica e social no Nordeste, apresenta-se como alternativa para a produção do biodiesel. O experimento objetivou avaliar, em escala real, os aspectos produtivos da cultura da mamona irrigada com esgoto doméstico tratado. Empregou-se o sistema de microaspersão; a delimitação experimental foi de quatro repetições e quatro tratamentos: T1: água do poço e adubação recomendada; T2: esgoto doméstico tratado e adubação recomendada; T3: somente esgoto doméstico tratado e T4: esgoto doméstico tratado e metade da adubação recomendada. Verificou-se que as unidades irrigadas com esgoto tratado superaram as irrigadas com água, em quase todas as variáveis analisadas. A produtividade foi maior nos tratamentos irrigados com esgoto e adubação (T2) e (T4), alcançando produtividade de 1.986 e 1.412 kg ha -1 , respectivamente. O teor de óleo contido nas sementes foi analisado e não apresentou nenhuma diferença significativa entre os tratamentos com adubação (T1, T2 e T4), sendo que o tratamento com esgoto tratado (T3) forneceu baixíssimos teores de óleo na semente. Palavras-chave:Ricinus communis, reúso, biodiesel, produção Productivity of castor bean irrigated with treated domestic sewage ABSTRACTThe castor bean (Ricinus communis L.), an oil crop of economic and social importance for the Northeast region of Brazil, can be used for biodiesel production. The experiment aimed to evaluate, at a realistic scale, the productive aspects of the castor bean irrigated with treated sewage. Microsprinkler irrigation method was selected, and the experimental setup consisted of four repetitions and four different treatments: well water and recommended fertilization (T1); treated wastewater and recommended fertilization (T2); treated wastewater without external recommended fertilization (T3); and treated wastewater and half of recommended fertilization (T4). It was found that units irrigated with treated sewage exceeded the ones irrigated with well water in almost all variables. The highest productivities were in the treatments with wastewater and fertilization (T2) and wastewater and half of recommended fertilization (T4), reaching 1,986 and 1,412 kg ha -1 , respectively. The castor seeds oil content was also investigated, no significati difference among the treatments with recommended fertilization (T1, T2 and T4) was verified. The treatment tested with effluent without recommended fertilization (T3) provided very low oil content in the seeds.

No abstract

Many Missouri soils test high in extractable P after long periods of rock phosphate and processed P fertilization. This study was undertaken to determine the P‐supplying capacities of five Missouri soils possessing high levels of extractable P. Initial P levels were evaluated with selected extractants (Bray I, Bray II, Mehlich II, double acid, dilute SrCl2) and through evaluation of the P buffering index. Each soil was cropped under greenhouse conditions for 7 consecutive harvests of grain sorghum (Sorghum bicolor L. cv. Warner 744R). After each harvest, plant P uptake was calculated and extractable P measured as before. For each soil test, regression analyses of plant P uptake were performed. With only one exception, the decline in extractable P in all soils, as measured by all five extractants, was significantly correlated with cumulative P uptake. The highest correlations were obtained with Bray I for Sharkey clay (r = 0.95), Bray I and Bray II for Kennebec silty clay loam (r = 0.97), Bray II for Mexico silt loam and Broseley loamy fine sand (r = 0.95 and r = 0.90, respectively), and Mehlich II for Tiptonville silt loam (r = 0.96). Slopes of the decline in extractable P following intensive cropping show similarities between Bray I and Mehlich II, Bray II and double acid. The quantity of plant available P extracted by Bray II and dilute SrCl2 was found to be inversely related to the P buffer index (PBI). When extrapolating to critical P levels for Bray I (11 mg kg−1) and Bray II (24 mg kg−1) only the Bray II extracted predicted number of harvests in order of soil PBI.

ABSTRACT:The objective of this study was to evaluate the productive performance of sunflower plants irrigated with different levels of domestic treated sewage and groundwater well with different doses of nitrogen. It was used randomized blocks design in split-split plots with four replications. In the plots, we evaluated the effect of two types of irrigation water, in the subplots we evaluated the five irrigation levels expressed as 25, 50, 75, 100 and 125% of the Class A pan Evaporation (CAE), and in the sub subplots, we evaluated the effect of four different doses of nitrogen (25, 50, 75 and 100 kg ha -1 ). The irrigation of sunflower with domestic sewage produced greater yield potential of grain and oil. The use of water from treated wastewater can replace up to 50 kg N ha -1 without affecting productivity. It is recommended for the commercial production of sunflower the use of treated sewage water with irrigation depth relative to 100% of CAE (296.64 mm) and nitrogen of 25 kg ha -1 . KEYWORDS:Helianthus annuus, recycle, drip irrigation, nitrogen fertilization. IRRIGAÇÃO COM ESGOTO DOMÉSTICO TRATADO E DOSES DE NITROGÊNIO NA PRODUÇÃO DO GIRASSOLRESUMO: Objetivou-se, com este trabalho, avaliar o desempenho produtivo do girassol irrigado com diferentes lâminas de esgoto doméstico tratado e de água de poço freático, e diferentes doses de nitrogênio. Utilizou-se do delineamento estatístico de blocos ao acaso, no esquema de parcelas subsubdivididas, com quatro repetições. Nas parcelas, avaliou-se o efeito dos dois tipos de água de irrigação; nas subparcelas, as cinco lâminas de irrigação baseadas em percentuais da evaporação do tanque classe A (ECA), que corresponderam à multiplicação da ECA pelos fatores 0,25; 0,50; 0,75; 1,00 e 1,25; e nas subsubparcelas, o efeito das quatro doses de adubação nitrogenada (25; 50; 75 e 100 kg ha -1 ). A irrigação do girassol com esgoto doméstico promoveu maiores potenciais produtivos de grãos e de óleo. O uso da água proveniente de esgotos domésticos tratados pode substituir até 50 kg de N ha -1 , sem afetar a produtividade. Recomenda-se, para a produção comercial do girassol, o uso do esgoto doméstico tratado com a lâmina de irrigação referente a 100 % da ECA (296,64 mm) e adubação nitrogenada de 25 kg ha -1 .

The objective of this study was to analyze the effect of soil fertilization with sulfur-based fertilizers, sulfate and elemental sulfur forms on biomass production, nutrient characteristics of sorghum and soil chemical properties. The experiment was carried out in a 4 x 4 factorial scheme (four sulfur sources: single superphosphate, agricultural gypsum, elemental sulfur powder and elemental sulfur granulated with bentonite, and four sulfur doses: 0, 40, 80, 120 mgdm-3) using four replications in a completely randomized design, being cultivated in pots under greenhouse conditions. The sorghum was cultivated for a period of 51 days after emergence of the seedlings. The shoot dry mass, shoot macronutrients content, root and soil and pH of the soil were evaluated. There were interactions between sources and sulfur doses in the variables such as shoot dry mass, sulfur in the root, sulfur and calcium in the soil. Elemental sulfur (granulate) showed lower concentrations of phosphorus, sulfur and N:S ratio in the shoot. The concentrations of potassium, calcium and magnesium did not show significant differences, both for the shoot and the root. The pH of the soil was reduced depending on the sources and doses of elemental sulfur. The sources and doses of sulfur did not influence the levels of phosphorus, potassium, and magnesium in the soil. The elemental sulfur in the form of powder is the best source of sulfur for forage sorghum cultivated in soil with alkaline pH.