Open Access Original Research Article

Spatial Distribution of Rubber Tree Dendrometrics Variables and Soil Chemical Attributes

Julião Soares de Souza Lima, Adilson Almeida dos Santos, Samuel de Assis Silva, Marcelo Soares Altoé

Journal of Experimental Agriculture International, Page 1-13
DOI: 10.9734/JEAI/2018/41520

To know the relations between the developments of the crops and the chemical attributes of the auxiliary soil in their management. This work aimed to examine the spatial and temporal variability of rubber tree dendrometric parameters (Fx 3864 clone) and soil chemical attributes P (phosphorus) and K (potassium) levels. Diameter at breast height (DBH), height (HGT) and volume (VOL) of 200 trees were measured at three different periods. A total of 60.0 soil samples was also randomly collected from soil layers 0.0 – 0.20 m and 0.20 – 0.40 m depth. Data were submitted to descriptive statistics, correlation analysis and geostatistics. The rubber tree height measured at the first and second periods correlated significantly with the P and K levels from the 0 – 0.20 m layer and with the P level from the 0.20 – 0.40 m layer. For the third measuring period, the rubber tree parameters correlated significantly with the K level from the 0 – 0.20 m layer. Dendrometric variables of rubber trees exhibit strong spatial dependence at the early tree growth stage.

Open Access Original Research Article

Solanum melongena L. Ecophysiology under the Influence of Meloidogyne javanica

Francisco Romário Andrade Figueiredo, Jackson Silva Nóbrega, João Everthon da Silva Ribeiro, Toshik Iarley da Silva, Fernando José da Silva, Rodrigo Garcia Silva Nascimento, Manoel Bandeira de Albuquerque, Guilherme Silva de Podestá, Riselane de Lucena Alcântara Bruno

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/JEAI/2018/41523

Aim: The purpose herein was to quantify the ecophysiological exchanges of eggplants cv. Embu (Solanum melongena L.) conducted with and without Meloidogyne javanica.

Study Design: The experimental design has completely randomized with two groups of plants (with and without soil infestation) with five replications and two plants per pot (treatment).

Place and Duration of the Study: The experiment has carried out at the Agrarian Sciences Center of the Federal University of Paraíba, Areia, PB, between October to December, 2017.

Methodology: The eggplant cultivar employed was ‘Embu’. Its seedlings were transplanted to 5 dm3 pot, filled with a substrate formulated by the mixture of vegetal soil, sand, and cattle manure in the proportion of 3:1:1.Their growth characteristics were valuated after 60 days of transplant (DAT), when the following variables were measured: plant height; stem diameter; leaf number; flower number; and aerial part, root, and total dry masses; and Dickson quality index. Gas exchange evaluations were performed between 7:00 a.m. to 5:00 p.m. The level of chlorophyll under fluorescence emission was measured several times.

Results: There was no significant difference for the variables, growth, fluorescence and chlorophyll between plants with and without M. javanica inoculation, which proved that they were resistant to the population level to which they were encountered. Plants inoculated with M. javanica, there was a greater increase of the CO2 assimilation rate and in the carboxylation efficiency.

Conclusion: Therefore, we can say that these plants have mechanisms to control their photosynthetic activities, which make them resistant to M. javanica stress, avoiding growth damages.

Open Access Original Research Article

Spatial Correlation between Eucalyptus Diameter at Breast High and Particle Size Fractions of an Oxisol

Julião Soares de Souza Lima, Diego Antonio Ottonelli de Bona, Nilton Cesar Fiedler, Vagner Mauri Quinto, Samuel de Assis Silva

Journal of Experimental Agriculture International, Page 1-10
DOI: 10.9734/JEAI/2018/41521

Field growth of Eucalyptus is influenced by physical attributes of soils, which justifies comprehensive studies on these relationships within a forest system. This work was aimed at studying the spatial variability in the diameter at breast high (DBH) of Eucalyptus, trees cultivated over three years and its relationships with the particle size fractions of a Oxisol. The study was conducted on a 33.0 x 33.0 m sampling grid, totalling 94.0 georeferenced field spots. Soil samples were collected from the 0 – 0.20 m and 0.20 – 0.40 m depth layers to determine the particle size fractions and DBH was measured in 5.0 neighbour Eucalyptus trees, with average DBH centered at each georeferenced spot. Data were submitted to descriptive, multivariate and geostatistical analyses. Maps were built using ​​interpolated ordinary kriging and cokriging, while principal component analysis (PCA) was performed on the clay and total sand fractions from both soil layers. The correlation coefficients between the original variables and the first principal component (PC1) were large and negative and positive in relation to the clay and total sand fractions, respectively. The primary variable DBH was successfully estimated by cokriging using the PC1 score as a secondary variable. The simple and cross semivariograms of the DBH adjusted to the spherical model. The cokriging technique was found to be an efficient tool in estimating variables within forest production systems with reduced sampling cost.

Open Access Original Research Article

Physico-Chemical Characteristics and Carbon Balances in a Fluvic Entisol after Six Years of Fertilization with Manure and Gliricidia

Dário Costa Primo, Rômulo Simões Cezar Menezes, Renison Neponuceno de Araujo Filho, Emmanuel Damilano Dutra, Eraldo Rodrigues da Silva, Romildo Nicolau Alves, Everardo Valadares de Sá Barretto Sampaio, Antonio Celso Dantas Antonino, Eduardo Henrique Lima de Lucena

Journal of Experimental Agriculture International, Page 1-11
DOI: 10.9734/JEAI/2018/41694

Soils in the semi-arid region of northeastern Brazil have low natural fertility and therefore, plant growth and productivity can be adversely affected. The application of mineral fertilizers is economically unfeasible by farmers in this region. The use of organic inputs found in farms, such as animal manure and the biomass of gliricidia leaves and branches (Gliricidia sepium Jacq. Walp), is a viable and low-cost option. Thus, the objective of this study was to evaluate influence of organic fertilizations over six years on the physical and chemical characteristics of a Fluvic Entisol cultivated with beans, cotton, corn and sunflower was evaluated. Fertilizations, of 20 Mg ha-1 year-1, were: GI - soil-incorporated gliricidia; GS - surface gliricidia; EI + GI - manure and incorporated gliricidia; EI + GS - soil - incorporated manure and surface gliricidia, EI - soil - incorporated manure; and control - without addition of organic fertilizer. In the combined applications, half the fertilizer came from each source. All fertilization systems decreased bulk density, compared to the control treatment, and in the EI + GS system, there was an increase in total soil porosity. The GS system resulted in the largest SOM stocks and C / N ratio. The EI + GI system increased the total phosphorus stock. The use and application of gliricidia biomass as a green fertilizer over time improves the soil physical and chemical conditions, promotes good agricultural productivity without the need of mineral fertilizers, being an alternative of high relevance in the reduction of costs in agricultural practices.

Open Access Original Research Article

Productive Aspects of Tropical Grasses under Different Soil Water Stresses

Morgana Scaramussa Gonçalves, Wilian Rodrigues Ribeiro, André Alves Pinheiro, Camila Aparecida da Silva Martins, Antônio Carlos Cóser, Edvaldo Fialho dos Reis, Giovanni de Oliveira Garcia

Journal of Experimental Agriculture International, Page 1-12
DOI: 10.9734/JEAI/2018/41808

For irrigation management, the methods that estimate the content and matric potential of available water in the soil that restricts the development of grasses are used. In this way, the objective was to evaluate the productive aspects of grasses in protected environment submitted to water stresses in the soil. Thus, in the experimental area of the Center of Agrarian Sciences and Engineering of the Federal University of Espírito Santo, at the geographic coordinates of 20º75'59'' South latitude, 41º48'24'' West longitude three experiments were implemented: Mombaça, Tifton 85 and Marandu, was conducted in a completely randomized design with five repetitions in a scheme of subdivided parcels, with the plots levels of water stress factor in the soil (20, 40, 50, 60 and 70 kPa) and the subplots levels 1st, 2nd and 3rd of cutting factor. The variables analyzed were aerial and root dry mass. Results showed that tensions do not provide differences in the dry mass for Mombaça forage. For Marandu higher dry mass results were obtained in 50, 60 and 70 kPa and for Tifton 85 in 20 and 60 kPa. In the tension of 60 kPa provided higher root dry weight for Mombaça; for Marandu, in the tensions of 20, 50, 60 and 70 kPa, while for the Tifton 85 no difference between soil water tensions was verified. It was observed that the higher production of dry mass demanded the larger water slides.