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۱Production of Sunflower and Biomass Depending on Available Soil Water and Nitrogen Levels
اطلاعات انتشار: Iranica Journal of Energy & Environment، دوم،شماره۴، ۲۰۱۱، سال
تعداد صفحات: ۷
In order to study the effects of nitrogen and available soil water levels on growth and yield components of sunflower (cv. Embrapa 122 \ V–2000), an experiment was carried out from November 2009 to October 2010 in the Agricultural Engineering Department of the Federal University of Campina Grande, Campina Grande, Paraiba, Brazil. The treatments were arranged as a completely randomized design, in a 4×4 factorial experiment (four nitrogen levels and four available soil water levels), with three replications, totaling 48 experimental units. The nitrogen (N) levels in kg haG1 were: 0; 60; 80 and 100 added as urea; the available soil water (AW) levels were 55; 70; 85 and 100%. In conclusion, this study showed that the application of nitrogen fertilizer levels and available soil water levels led to significant increase in growth and production traits except for the dry weight of 1000 seeds.

۲Effects of Different Soil Management Systems in the Chemical Properties in the Coastal Plains of State Paraiba
اطلاعات انتشار: Iranica Journal of Energy & Environment، دوم،شماره۴، ۲۰۱۱، سال
تعداد صفحات: ۱۷
This study evaluated the chemical characteristics of soils under different management systems, i.e., the culture of sugar cane with and without vinasse compared to forest area in the Coastal Plains of State Paraiba. For each management system were opened five profiles occurring in the same soil class, dystrophic Ultisol grayish. In each profile, the soil samples were collected at 0–5, 5–10, 10 20 and 20–40 cm depths. These samples, after being air dried and passed through a sieve of 2 mm, were characterized chemically. Data were analyzed using descriptive statistics, analysis of variance and Tukey test at 5% probability. The pH, electrical conductivity, exchangeable aluminum, potential acidity and phosphorus results, in relation to soil management, were significantly affected; in relation to depth, there was a significant effect on the pH results and on the electrical conductivity, calcium, sodium, potassium, potential acidity and P results. However, for area x depths there was a significant difference only for aluminum, potential acidity and phosphorus contents. The results of this study show that treatment with vinasse application promotes improvements in soil chemical properties such as pH increases and the availability of K and P in the surface layers of soil.

۳Phosphate Sorption in Oxisols in Paraíba State, Brazil, Classified as Solution Equilibrium Phosphorus
اطلاعات انتشار: Iranica Journal of Energy & Environment، سوم،شماره۱، ۲۰۱۲، سال
تعداد صفحات: ۶
Aiming to evaluate the phosphorus adsorption in Oxisols with phosphorus remaining classified using the Langmuir isotherm, a study was developed in the laboratory at Federal University of Campina Grande, PB, with samples of the surface layer (0–20 cm) of three Oxisols of the State of Paraíba, differentiating among these the classification of the remaining P–values. The phosphorus levels for adjusting the isotherm were defined based on the remaining P–values. To assess the maximum P adsorption capacity data from P adsorbed and equilibrium concentrations of the solutions were adjusted Langmuir isotherm. This isotherm model could satisfactorily describe the adsorption of phosphorus in soils. The Oxisol sample with high P–rem was the highest value of maximum P adsorption capacity. The maximum P adsorption capacity was correlated with CEC and Ki for the samples classified as P–rem medium and high, respectively.

۴Response of Sunflower to Nitrogen Application and Water in Northern Brazil Alfisol
اطلاعات انتشار: Iranica Journal of Energy & Environment، سوم،شماره۳، ۲۰۱۲، سال
تعداد صفحات: ۷
Decline in crop yield has been a problem in Northern Brazil region due to inherent low fertility status of the soils and water deficit of different crops. In order to study the effects of nitrogen and available soil water levels on growth and yield components of sunflower, an experiment was carried out from March to June 2010 in a semi–controlled greenhouse condition of the Federal University of Campina Grande, Paraiba, Brazil using Alfisol soil. The treatments were arranged as a completely randomized design, in a 4×4 factorial experiment (four nitrogen levels and four available soil water levels), in triplicates, total of 48 experimental units. The nitrogen levels in kg\ha were 0; 60; 80 and 100 which was added as urea; the available soil water levels were 55; 70; 85 and 100%. The results of this research indicate that nitrogen had a significant effect only on leaf area at 40 DAS and % achenes viable. The effect of available soil water on sunflower cv. Embrapa 122\V–2000 biometry and the yield showed that there were significant differences, on average, in all growth traits (stem height and diameter) at 40 and 60 DAS, in leaf number at 40 DAS, in leaf area at 40 and 60 DAS and in all production traits. The biometry and yield response to available soil water of different crops is of major importance in production planning. In this study, the maximum biometry and yield response factor of sunflower was determined at 100 % of available soil water.

۵Growth of cocoa as function of fertigation with nitrogen
اطلاعات انتشار: Iranica Journal of Energy & Environment، سوم،شماره۴، ۲۰۱۲، سال
تعداد صفحات: ۵
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