Open Access Original Research Article

Effect of Salinity on Germination of Lettuce Cultivars Produced in Brazil

Jorge Tadeu Fim Rosas, Edilson Marques Junior, Rodrigo Monte Lorenzoni, Fernando Ferreira Lima dos Santos, Rodrigo Nogueira Martins

Journal of Experimental Agriculture International, Page 1-8
DOI: 10.9734/jeai/2019/v34i530183

The challenge of recovering degraded soils due to salinity excess leads to the search for more effective strategies that can overcome this problem. Among these, one of the approaches is the use of resistant plant varieties in affected areas. This study aimed to evaluate the influence of different doses of salts on seed germination and seedling formation of two lettuce cultivars (Hanson and H121) and to verify the existence of tolerance among the cultivars. A completely randomized design was used in a 2x5x4 factorial scheme, where the cultivars were evaluated under five distinct salt doses (0, 25, 50, 75 and 100 mol.m-3, conductivities of 0.0, 2.8, 5.4, ​​8.0 and 10.6 dS.m-1, respectively), with four replicates. In this sense, the following variables were evaluated: germination rate (GR), germination speed index (GSI), seedling height (SH), root length (RL) and percentage of dry matter in relation to fresh matter (DM%). As a result, the Hanson cultivar presented better performance than the H121, under all the different salt doses, in all the studied variables. Also, the EC of 2.8 dS.m-1 did not affect any of the studied variables, including both cultivars. However, EC above 2.8 dS.m-1had, significantly, reduced the development of the cultivars. The Hanson cultivar was influenced only in the variables SH, RL and DM%, where and DM% were influenced by EC values above 8.0 and 10.6 dS.m-1, respectively. The cultivar H121 was significantly influenced by all evaluate dvariables, which demonstrates its greater susceptibility to salinity.

Open Access Original Research Article

Yield and Characteristics of Melon Fruits under Different Fertilization Management and Soil Cover

Jackson Teixeira Lobo, Witalo da Silva Sales, José Fabrício Alves Feitosa, Juscelino Martins Costa Junior, Reynaldo Teodoro de Fatima, Daniel de Almeida Carreiro, Felipe Thomaz da Camara

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/jeai/2019/v34i530184

Aims: To evaluate the 'Canary' and 'Hale's Best Jumbo' melon yield and fruit characteristics as a function of fertilization management and soil cover with mulch.

Study Design: The design was a randomized complete block design in a 2x3x2 factorial scheme, with three replications and seven plants per plot.

Place and Duration of Study: The experiment was conducted from June to September 2015, at the Center of Agrarian and Biodiversity Sciences of the Federal University of Cariri, located in the city of Crato, Cariri region, Brazil.

Methodology: Two varieties of melon ('Canary' and 'Hale's Best Jumbo') were studied under three fertilization managements (mineral fertilization via soil, mineral fertilization via soil + organic fertilization and mineral fertilization via soil + foliar fertilization) with the presence or absence of soil cover with polyethylene mulch.

Results: The use of mineral + organic fertilization and mineral + leaf fertilization promoted an increase in fruit mass and yield of approximately 3.93 t ha-1 (25.50%) and 4.64 t ha-1 (30%), respectively. Both melon cultivars presented the best responses grown on plastic mulch, with yield increases of 79.66% and 26.16% for 'Canary' and 'Hale's Best Jumbo', respectively. Moreover, the 'Hale's Best Jumbo' cultivar presented higher soluble solids contents than the 'Canary' melon, with an increase of 11.26% (0.76 ° Brix).

Conclusion: The use of soil cover and additional fertilization (organic or foliar) in the cultivation of melon provides an increase in size, mass and productivity, while soil cover increases the soluble solids content in fruits.

Open Access Original Research Article

Components of Tree Biomass in an Integrated Crop-Livestock-Forest System

Tatiana Vieira Ramos, Jorge Luís Sousa Ferreira, Carlos de Melo Silva Neto, Francine Neves Calil, Isabela Carolina Silva, Ualace Marciano Carrijo

Journal of Experimental Agriculture International, Page 1-12
DOI: 10.9734/jeai/2019/v34i530185

Aims: This study performed the adjustment of volumetric models, and determined the biomass of Eucalyptus grandis x Eucalyptus urophylla hybrid cultivated in a crop-livestock-forest integration system (CLF).

Study Design: The experimental area consists of a crop-livestock-forest integration system where trees are hybrids clones of seven year old Eucalyptus grandis x Eucalyptus urophylla.

Place and Duration of Study: This work was carried out at Fazenda Santa Brígida, Ipameri, Goiás (Brazil).

Methodology: A forest inventory of the area was carried out in October 2015 when the tree component was fully developed. Diameter at breast height (DBH) (at 1.30 m) and total height (H) of trees were measured in the field and categorized according to 4 classes. Afterwards, 12 trees were felled, which were cubed and compartmentalized to determine the volume and biomass of their components. The volumetric models developed by Schumacher & Hall and Ogaya were applied to obtain determination coefficients.

Results: The average DBH was 18.28 cm and the average H was 23.47 m. The highest volumes of wood were observed in the diametric classes that presented the largest number of individuals, however in the class of higher DBH an average individual volume of 0.36 m3 of wood was observed. The total biomass of Eucalyptus was 56.64 Mg ha-1, being 83.70% wood, 6.52% in branches, 6.37% in bark and 3.40% in leaves.

Conclusion: The volumetric models developed by Schumacher and Hall as well as Ogaya were found to be applicable for estimating the volume of wood in CLF systems, where both showed a determination coefficient of 0.866.

Open Access Original Research Article

Impacts of Meteorological Attributes on Agronomic Characteristics of Sunflower Cultivated in the Cerrado

Dayana Aparecida de Faria, Dryelle Sifuentes Pallaoro, Murilo Ferrari, Aloisio Brigido Borba Filho, Joadil Gonçalves de Abreu, Elisangela Clarete Camili, Anne Caroline Dallabrida Avelino, Kyron Cabral Sales, José Holanda Campelo Júnior, Claudio Guilherme Portela de Carvalho

Journal of Experimental Agriculture International, Page 1-7
DOI: 10.9734/jeai/2019/v34i530186

The sunflower has adaptation for cultivation in Brazilian conditions and the main product is the oil extracted from the seeds. This study aimed to verify the impacts of meteorological attributes on agronomic characteristics of sunflower genotypes cultivated as a second crop, in Mato Grosso, Brazil. The experimental design was randomized complete block design (RCBD), cultivating the two sunflower genotypes, M734 and Hélio, in three years (2009, 2011, 2012) with four replications. The agronomic characteristics evaluated were: plant height, capitulum diameter, weight of a thousand achenes, yield of achenes, oil content and oil yield. Then, water deficit and the maximum crop yield are estimated for correlation analysis between meteorological attributes and agronomic characteristics. In both genotypes studied there was a very strong correlation between plant height with evapotranspiration (r=0.99*) and very strong negative correlation (r=-0.99*) with water deficit. For mass of a thousand achenes, there was a very strong negative correlation with the maximum (r=-0.98*) and minimum (r=-0.96*) temperatures, and with evapotranspiration (r=-0.98*) in the Helio 358. In addition, effect of the water deficit on the oil yield (r=-0.98*) was verified for the same genotype. Very strong negative correlation was found between maximum temperature and oil content (r=-0.96*) in genotype M734. In sunflower cultivation in Mato Grosso, Brazil, water deficit reduces plant height, capitulum diameter and oil yield. The oil content of the achenes reduces when the maximum temperature increases, during the cultivation. For those reasons, the use of sunflower genotypes with shorter cycles and the earlier sowing could benefit the crop developing, by suiting the management, to avoid unfavorable climatic conditions that can cause reduction in production parameters.

Open Access Original Research Article

Selection of Models for Above-Ground Biomass in a Eucalyptus urograndis Stand

Renata Reis de Carvalho, Dione Richer Momolli, Mauro Valdir Schumacher

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/jeai/2019/v34i530187

The quantification of biomass is an important tool that helps the forest manager to define the course of the enterprise and the best management techniques. In view of this situation, the objective of the present study was to perform the modeling of above - ground biomass in the different components in Eucalyptus urograndis stands at 4.5 years of age. The stand is located in the south of Brazil, municipality of São Gabriel. Four plots of 577.5 m² were installed and all DBH and heights of 20% of the trees were measured. Four diameter classes were defined, with 3 trees being felled in each of them. All the biomass was weighed in leaves, branches, bark and wood and through samples the moisture content in each component was determined. The modeling showed reliability of 96% for wood estimation and biomass total. The total biomass was 65 Mg ha-1, of these, 72% of wood. The modeling with stepwise procedure presented good distribution of the residues. Through the easily obtained variables such as DBH and height it is possible to determine the volume of biomass accurately.