José Dantas Neto

Eficiência no uso da água na cana-de-açúcar sob diferentes lâminas de irrigação e níveis de zinco no litoral paraibano

The study was conducted in an experimental area of the Capim II Farm, located in the municipality of Capim - PB, Brazil, with the objective of determining the efficiency in the use of the water (WUE) for the sugarcane crop (Saccharum officinarum L.), cultivar SP 79-1011. The experimental design consisted of randomized blocks, with three replications in a 5 x 5 factorial design. The irrigation treatments were: rainfed; 25; 50; 75 and 100% of the ETc (1,026.57 mm) with the respective effective precipitations of 780.06; 713.31; 487.54; 243.71 and 194.51 mm. The levels of zinc studied were 0; 1; 2; 3 and 4 kg ha-1. The irrigation equipment used in the study was a central pivot with irrigation frequency of nine days. The water use efficiency (WUE) of sugarcane crop in terms of cane production and of sugar increased with the depth of water applied. For the Coastal Table Lands of northern Paraiba, the maximized WUE for sugarcane and sugar production is 7.12 and 0.67 kg m-3, respectively.

Uma medida de sustentabilidade ambiental: pegada hídrica

The concept of the water footprint has been recently introduced as an important indicator for human induced water consumption. The water footprint is defined as the total volume of water used during production and consumption of goods and services as well as direct water consumption by human beings. Water is not only consumed directly but also indirectly in production processes. Therefore, calculating the water footprint enables to quantify total water consumed along the whole global supply chain. This review surveys the state of the art on water footprint since the International Expert Meeting on Virtual Water Trade, held in Delft, The Netherlands, in December 2002, until current days. The major findings linked to the consulted literature indicated that the water footprint is suitable for monitoring the human impact on the environment. Furthermore, this methodology has a wide range of applications that can be used at scales ranging from a single product, process, industry, individual, cities and even nations around the globe.

Wet bulb dimensions in surface drip irrigation

Information on the geometry of wetted soil volume under trickle irrigation is important for design and operation of this irrigation system, and also for the management of the irrigation. For this, six experiments were installed in different soils with the objective of evaluate the dimensions of the wetted bulb as function of emitter discharged and water application time, using the power model. It was concluded that the wetted bulb dimensions can be predicted satisfactorily using the power model for all the soils tested.

Computer simulation of a Rietema-family hydrocyclone used in irrigated agriculture

The hydrocyclone is a centrifugal separator that has been used for over 50 years in the chemical processing and mining industries. In irrigated agriculture in Brazil it is not used as often. One reason for this is the poor understanding by designers of the complex phenomena involved in the internal flow of the hydrocyclone, and the lack of knowledge of new computational tools available on the market. This study evaluates the use of Computational Fluid Dynamics (CFD) as a potential tool to be used in the design and optimisation of hydrocyclones used in irrigated agriculture. A 50 mm Rietema-family hydrocyclone is simulated using CFD. The turbulent flow inside the hydrocyclone is modelled using the Reynolds Stress Model, and a Eulerian approach is employed to model the multiphase flow. Numeric validation is performed by comparing the results of the simulation with data found in the literature. The global mass balance observed for both the single-phase and multiphase flows shows good agreement of the obtained results with data in the literature. Furthermore, the static pressure field, the axial and tangential velocity and the volume fraction of sediments in the hydrocyclone are obtained. The article shows that CFD is a useful tool in explaining the process of sediment separation in the hydrocyclone, and can therefore be used in the design and optimisation of such equipment.

Deterioração físico-conservacionista da microbacia hidrográfica do riacho Paus Brancos, Campina Grande, PB

The objective of the present study consisted in the diagnosis of the physical conservationist deterioration of the microbasin of the Paus Brancos Stream, Campina Grande, PB, in the semi-arid region of Paraiba state. The microbasin was divided in 11 minibasin. The methodology consisted in determination of the rugosity coefficient (Ruggdeness Number - RN), using the physical characteristics of the minibasins and the distribution of land use classes using the rugosity coefficient. In the studied area the physical conservationist deterioration is high (34.91%), contributing to this the small vegetable covering 232.15 ha (10.05%). There is availability of many areas for the agriculture but their utilization depends on auxiliary diagnosis. Although there are only 172.37 ha (7.48%) in conflicts, for the perfect environmental equilibrium of the microbasin, 1,286.14 ha (55.68%) need to be worked out. No class A minibasin presented excess of agricultural area. The deteriorated area in the studied microbasin is 507.35 ha (21.97%).

Nutritional status of orange tree ‘Pêra Rio’ variety after Huanglongbing disease infection, leaf spray fertilization and application of resistance-inducing bioinductors

Citrus industry is widespread in the world. The Huanglongbing is an important disease of citrus species and has been spread around the world. This research analyzed the nutritional status of tree ‘Pêra Rio’ variety infected with Candidatus Liberibacter spp., under leaf nutrients spray and bioinductors of resistance. The experiment was carried out from September 2013 to June 2014, in a citrus commercial orchard located in the city of Ibitinga (SP). A completely randomized design was used in a factorial 3 × 4 × 6, consisting of three plants status (healthy, infected with asymptomatic HLB, and symptomatic HLB), four rates of spray solutions (0, 2, 4 and 6 L ha), six application stages (A1, A2, A3, A4, A5, and A6 with intervals of 45 days between each stage) and four replications. Macro and micronutrients leaf levels were quantified. Data were submitted to exploratory factor analysis with multivariate statistics. Three factors were extracted from the variables, namely, Factor 1 formed by variables S, Cu, Fe, and Zn; Factor 2 by N, K and B, and Factor 3 by Ca, Mg, and Mn. ‘Pêra Rio’ plants nutritional status was destabilized with the infection of Candidatus Liberibacter spp. Progressive treatment with leaf fertilization and resistance bioinductors temporarily re-established nutritional standards of plants affected by Huanglongbing but did not promote stability of the plants nutritional status.

Growth and plant mass of radish fertirrigated with different doses nitrogen

The objective of the present study was to evaluate the effect of nitrogen doses applied via fertigation and associated with different types of crop establishment fertilization on growth and biomass of radish. The experiment was conducted in a greenhouse of the Academic Unit of Agricultural Engineering, Federal University of Campina Grande, from April to May 2014. Treatments consisted of five doses of nitrogen fertilizer applied by fertigation (0, 0.7, 1.4, 2.1 and 2.8g per pot) and three types of crop establishment fertilization (humus 2:2; NPK and control), arranged in a 5 x 3 factor design with four repetitions. The 15 treatments were arranged in 60 plots. The nitrogen source used in the study was urea, divided in three applications: the first application was carried out eight days after transplanting, the second, on day 15, and the third, on day 22. The crop establishment fertilization significantly influenced the growth variables and plant mass of the radish on day 35 after transplanting. The highest values of the variables (number of leaves, plant height, bulb diameter, leaf area, fresh mass of the aerial part, dry mass of the aerial part and root/aerial part were observed in the treatment with humus on day 35 after transplanting. The dose of 2.8g nitrogen per pot corresponding to 6.22g of urea per plant provided the highest yield for the variable number of leafs, leaf area and root length on day 35 after transplanting.

Índices de áreas verdes públicas no perímetro central da cidade de Juazeiro do Norte – CE (Indices of public green areas the central perimeter of the city of North Juazeiro - CE)

A qualidade ambiental fornece diversos beneficios para as zonas urbanas dentre elas reducao da temperatura e protecao do solo contra a impermeabilizacao. Assim, objetivou-se com este trabalho quantificar o indice de areas verdes publicas da cidade de Juazeiro do Norte - CE, realizando o calculo do indice de areas verdes por habitantes. O procedimento utilizar o somatorio das areas em m² dividindo pela populacao da area estudada. Para isso foi utilizado imagens do Google Earth exportadas para o Civil 3D permitindo obter a area das pracas e do parque da cidade. Os indices de area verdes publica e total da cidade de Juazeiro do Norte – CE, foram considerados abaixo do recomendado pela ONU. O bairro Jose Geraldo da Cruz e o unico que apresenta indice de area verde acima do recomendado com 14,88 m2.hab-1. Onze dos bairros estudados nao possui area verde contribuindo para o aumento da temperatura urbana. O crescimento desordenado da zona urbana, associado ao descaso do poder publico nos bairros mais perifericos da cidade resultam em deficits permanentes e crescentes das areas verdes de forma proporcional ao espaco urbano. A B S T R A C T The environmental quality provides many benefits to urban areas among them reducing the temperature and protection against soil sealing. Thus, the aim of this work was to quantify the level of public green areas of the city of north Juazeiro - CE, performing the calculation of the index of green areas per in habitant. The procedure using the sum of the areas in square meters divided by the population of the study area. For this we used Google Earth images exported to Civil 3D so obtain the area of squares and the city park. The indices of the total public and the city of Juazeiro green area - CE were considered below the recommended UN. Jose Geraldo da Cruz neighborhood is the only one that introduces green area index above recommended with 14.88 m 2 .hab -1 . Eleven of the neighborhoods studied has no green area contributing to the increase in urban temperature. The uncontrolled growth of the urban area, associated with the neglect of public power in the more peripheral areas of the city result in permanent and growing deficits of green areas proportional to shape urban space. Key words: urban zone, environmental quality, urbanization, index Public green areas, temperature

PERMANENT PRESERVATION AREAS: THE APPLICABILITY OF ENVIRONMENTAL LEGISLATION ACROSS THE WATER RESOURCES OF THE BRAZILIAN SEMIARID

The new environmental legislation refers in relation to the Permanent Preservation Areas (APP’s) equally for the entire national territory, not taking into account the specific environmental characteristics of each ecosystem, which has physiographic aspects, hydrological regime of the courses of water and dynamics of different land use. Thus, we sought to study to analyze the applicability of the New Forest Code about the Permanent Preservation Areas facing the problem, especially water resources of the Brazilian semiarid. Forward, there is the watershed Riacho Fundo located in the state of Paraiba, in the semiarid region that suffers from climatological issues, it has the lowest rainfall in the country, as well as environmental problems and use / disordered occupation. With the implementation of the new Law 12651/12, specified areas of APP’s have been reduced by 14.99% (Law 4771/65 old) to 5.31% of the total area of the watershed that is of 3757.89 hectares. However, it is essential that there is a proper establishment of rules for the APP’s, especially considering the Caatinga biome and their specific since, in the semiarid region, the rivers that make up ecosystems are mostly intermittent and ephemeral and where the areas protected by the legislation are commonly used to ebb cultivation, responsible for the livelihood of many families in the dry season.

Environmental and deteriorating state analyses of the watershed Riacho do Tronco, Boa Vista, PB, Brazil

Nesta pesquisa foi proposto, a partir da subdivisao da microbacia do Riacho do Tronco em oito sub-microbacias, diagnosticar as aptidoes de uso/ocupacao das terras em cada uma, identificar as areas de conflitos de uso e o nivel de deterioracao ambiental da microbacia como um todo, subsidiando o ordenamento territorial e a minimizacao dos riscos a desertificacao. Fazendo-se uso de tecnicas de geoprocessamento e trabalho de campo, foram calculados os parâmetros que permitiram o estabelecimento do Coeficiente de Rugosidade de cada sub-microbacia, segundo metodologia adaptada de Rocha (1997), possibilitando a classificacao da aptidao natural destas. Os resultados demonstraram que quatro sao aptas para agricultura, tres para pecuaria e florestamento e uma apenas para florestamento; tambem se diagnosticou o uso e ocupacao das terras atual e foram identificados os conflitos de uso, no caso presente representados pela pratica de atividades dissonantes da vocacao natural das sub-microbacias, pelos percentuais de solo exposto e pelas areas de mineracao, presentes em algumas sub-microbacias; Dessa forma, a partir da analise das variaveis conflitos de uso, areas a florestar, disponibilidade ou excesso de areas agricolas e areas a serem trabalhadas para o manejo correto das sub-microbacias, foi possivel verificar que a Microbacia do Riacho do Tronco tem um percentual de deterioracao de 42,8%. A partir do exposto, evidencia-se um alto nivel de deterioracao ambiental, com consequente propensao a desertificacao, haja vista a area estar localizada no Semiarido brasileiro e as atividades economicas serem desenvolvidas sem preocupacoes conservacionistas, urgindo a adocao de acoes sustentaveis, a serem implementadas pelo poder publico e sociedade organizada.