Boanerges Freire de Aquino

Produtividade da mamona irrigada com esgoto doméstico tratado

The 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 set-up 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.

Crescimento da cultura do girassol irrigado com diferentes tipos de água e adubação nitrogenada

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 Ceara, 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.

Irrigation with domestic treated sewage and nitrogen fertilizing in sunflower cultivation

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.

Crescimento inicial de pitaia em função de combinações de doses de fósforo-zinco

With the aim to evaluate the role of zinc-phosphorus ratio in the initial growth of pitaia for provide information that supports the definition of production systems more suitable for the exploitation of this crop in Brazil an experiment was carried out, testing five levels of P (0, 75, 150, 225 and 300 mg dm-3) and Zn (0, 2, 4, 6 and 8 mg dm-3) were each nutrient levels, arranged in 5x5 factorial design with four blocks. For significant interaction (p <0.05) proceeded adjustment in response surfaces of type Y = β0 + β1 (A) + β2 (A)2 + β3 (B) + β4 (B) 2 + β5 (A). (B) + e. Estimates of phenotypic correlations were obtained considering only the range of doses of P and Zn that promoted the best answers to the access pitaya traits. Application of P and Zn, and P x Zn interaction affect both the availability of nutrients in the soil, roots and shoots, thus influencing the early growth of pitaya. The most satisfactory yields occur when there is 60 - 75 mg P dm-3 and 3.0 - 4.0 mg dm-3 of Zn in the soil and 4.5 to 6.0 g kg-1 and 150 mg of P Zn kg-1 in shoots. These levels were obtained for the combination of 150 to 225 mg dm-3 with P 4 - 6 mg dm-3 of Zn. The levels of P and Zn in the shoot and the sum of the length of cladodes (SCC) are the characters that have greater explanatory direct effects on dry weight of cladodes (MSC).

Supplemental Ca2+ does not improve growth but it affects nutrient uptake in NaCl-stressed cowpea plants

The growth and nutrient assimilation was evaluated in CaCl2- and CaSO4-supplemented cowpea plants subjected to salt stress (75 mM NaCl). The salinity significantly reduced the cowpea vegetative growth. The addition of CaCl2 in the growth medium did not significantly affect plant growth, while for the CaSO4, the beneficial effects of Ca2+ were moderate. Salinity increased the Na+, K+, Cl-, N and P content in the plants, however it decreased the content of Ca2+ and Mg2+. Increases in Ca2+ concentration in the nutrient solution caused decreases in the Na+ and Mg2+ contents and increases in Ca2+, K+, P, and Cl- contents. The supplemental Ca2+ may alleviate the Na+ toxicity and may improve nutritional and ionic balance in cowpea, but it cannot overcome the osmotic effects associated with the increased total salt concentration.

FRAÇÕES LÁBEIS DA MATÉRIA ORGÂNICA E ESTOQUES DE CARBONO EM NEOSSOLO QUARTZARÊNICO CULTIVADO COM CANA-DE-AÇÚCAR COLHIDA SEM QUEIMA

The permanence of sugarcane straw on the soil surface, in systems without the pre-harvest straw burning practice, directly affects the soil organic matter dynamics. The objective of this work was to evaluate the changes in total organic carbon (TOC), carbon in the light organic matter (CLOM) and particulate organic carbon (POC), and their carbon stocks in a typic Quartzipsamment cultivated for nine years with sugarcane crops, which were conducted without the pre-harvest straw burning practice, in Paraipaba, State of Ceará, Brazil. Disturbed and undisturbed soil samples were collected at depths of 0.0-0.025, 0.025-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.30 m, in the sugarcane crop area and in an adjacent native forest area, in order to quantify the TOC, CLOM and POC, as well as the carbon stocks accumulated in the layer 0.0-0.30 m related to these fractions (TOCSt, CLOMSt and POCSt). TOC content changes after nine years of sugarcane crops, conducted without pre-harvest straw burning, were found only in the layers 0.10-0.20 and 0.20-0.30 m. The CLOM varied only in the layer 0.025-0.05 m. The POC content changes were more noticeable than the changes in TOC and CMOL. The CLOM of the sugarcane crop area presented high similarity with TOC, which may affect their quantification in studies related to the soil organic matter dynamics. The sugarcane crop increased the TOCSt, POCSt and CLOMSt in the layer 0.0-0.30 m, compared with the adjacent native forest area.

FORMAS DE FÓSFORO E ADSORÇÃO EM NEOSSOLO CULTIVADO COM CANA-DE-AÇUCAR COLHIDA SEM QUEIMA

The objective of this study was to evaluate the adsorption of phosphorus (P) and changes in the concentrations of organic and inorganic forms of P in a Neossolo Quartzarênico (Typic Quartzipsamment) after 9 years of successive cultivation with sugar cane without burning to harvest. Therefore, two areas, one in which cane sugar was planted and a native forest reference area, located in the municipality of Paraipaba-CE, were selected. In each area, samples were collected at depths of 0−0.025, 0.025−0.05, 0.05−0.10, 0.10−0.20, and 0.20−0.30 m, and the levels of organic (Po) and inorganic (Pi) phosphorus obtained by sequential extraction, the remaining phosphorus, and the maximum adsorption capacity of phosphorus by the soil were determined. In general, the permanence of straw on the soil surface under sugarcane cultivation promoted the maintenance of Po levels in the surface layers of the profile. The Po accumulated predominantly in the Po fraction extracted with sodium bicarbonate in both areas. Regarding the Pi content, changes were more evident during cultivation due to the effect of successive phosphate fertilizer applications. The fraction extracted with 0.1 mol L sodium hydroxide was the most representative, with the highest levels of P uptake. P adsorption was influenced by the initial content of the nutrient in the soil and no relationship between P adsorption and organic matter content was observed. The highest level of adsorption was observed in the bottom layer of the forest area (133.3 mg kg ) and the lowest level of adsorption was observed on the surface layer of the area under sugarcane cultivation (59.5 kg mg).