Revista Brasileira de Engenharia Agrícola e Ambiental
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/10362
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Item Mechanized harvesting of conilon coffee plants using a self-propelled machine(Departamento de Engenharia Agrícola - UFCG, 2022-10-24) Souza, Gustavo S. de; Bouzan, Antônio M. B.; Infantini, Maurício B.; Silva, Samuel de A.; Almeida, Robson F. deCoffee is one of the main commodities of global agribusiness and of outstanding economic and social relevance for Brazil. The lack of labor and its high cost are factors that worry coffee producers, mainly during the conilon coffee harvesting, which is performed manually. This study aimed to evaluate the efficiency of a self-propelled harvester under different conditions of machine adjustment and conduction of the Coffea canephora crop and measure its influence on the cost of harvesting compared to manual harvesting. Harvesting speed (800 to 1600 m h-1), rotation of the vibrating rod cylinder (1.0 and 1.5 RPM), number of orthotropic branches (one, two, and three), and plants with and without plagiotropic branches in the lower third were assessed. The increase in harvesting speed reduced the efficiencies of stripping and harvesting and defoliation. Increasing from one to three orthotropic branches per plant increased harvesting and stripping efficiencies, fruit loss on the ground, defoliation, and reduced pending load. The management without plagiotropic branches showed higher harvesting efficiency, lower loss on the ground, and lower defoliation. Harvesting speeds from 800 to 1600 m h-1 reduced the total and unit costs up to 62% compared to manual harvesting. Increasing harvesting efficiency above 70% has reduced harvesting costs by up to 79% compared to manual harvesting.Item Litterfall decomposition of coffee shaded with Tectona grandis or in full sun(Departamento de Engenharia Agrícola - UFCG, 2022-01-14) Henrique, Nirvani S.; Maltoni, Katia L.; Faria, Glaucia A.Litterfall is an important source of soil nutrients, but its decomposition can be affected by the crop system used. The objective of this study was to evaluate litterfall decomposition and macronutrient stocks in coffee crop systems in shaded (SHCS) environments and those in full sun (FSCS). The experiment was conducted on a rural property in Cacoal, state of Rondônia, Brazil, in a 2 × 6 factorial scheme with two crop systems (SHCS and FSCS), and six litterfall decomposition evaluation times (0, 30, 60, 180, 300, and 360 days after the litterfall was returned to the soil (DAL)), with seven replicates. The constant of decomposition (k), half-life time (t1/2) at 360 DAL, and phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), and nitrogen (N) concentrations of the remaining litterfall were determined at each evaluation time. The litterfall in the SHCS had a greater weight loss and constant of decomposition and a lower half-life time at the last evaluation, and the weight loss increased as a function of decomposition time. The litterfall stocks of macronutrients N, P, K, Ca, and Mg showed a linear decrease throughout the decomposition time, and increases in sulfur stock were found at the last evaluation.Item Nutritional balance and its relationship to yield in a coffee field: Inferences from geospatial analysis(Departamento de Engenharia Agrícola - UFCG, 2020) Silva, Marcelo B. da; Partelli, Fábio L.; Gontijo, Ivoney; Caldas, Marcellus M.Information obtained from studies of spatial variability and the Diagnosis and Recommendation Integrated System (DRIS) may contribute to understanding better the relationship between mineral nutrient balance and factors that limit the crop yield. This study shows that nutritionally balanced plants may be associated with low productivity in Conilon coffee fields. The study was carried out on a highly productive Conilon coffee (Coffea canephora) field, in São Mateus, state of Espírito Santo, Brazil. A sample grid was established with 100 points, each point linked to one plant. Twenty pairs of leaves from each plant were collected from productive branches to create a sample for nutritional analysis. The rust incidence (Hemileia vastatrix), the presence of the coffee borer (Hypothenemus hampei), and the physical characteristics of the soil were evaluated in each sampled plant. DRIS and Nutrient Balance Index (NBI) were calculated, and from the yield data, they were characterized using descriptive statistics. Maps were created showing the spatial distribution of the NBI, yield, total sand, and incidence of rust and coffee borer. It was verified the low relationship between nutritional balance and yield in Conilon coffee, suggesting that non-nutritional factors also influenced plant production. In areas of the maps with high NBI, the plant’s nutritional balance was the main limiting factor of production, since most plants in this area produced less than the average productivity of the plants sampled. The use of a geostatistics tool combined with the NBI resulted in better understanding of the relationship between nutritional and non-nutritional variables on the Conilon coffee yield.Item Soil quality in two coffee crop systems in the Amazon biome(Departamento de Engenharia Agrícola - UFCG, 2020) Henrique, Nirvani S.; Maltoni, Katia L.; Faria, Glaucia A.The form of occupation of the state of Rondônia, Brazil, favored the extensive agriculture, which resulted in a fast deforestation. The removal of forests and inadequate soil management and use, combined with a hot and wet climate, affected the soil chemical, physical, and biological attributes. In search for less impacting and alternatives that promote greater soil conservation for coffee production in the North region of Brazil, the objective of this work was to evaluate the effects of two coffee crop systems on the soil chemical and microbiological attributes. The treatments consisted of a shaded coffee crop (SCC) and a full-sun coffee crop (FCC). A completely randomized design was used, with four clusters per treatment and seven sampling points per cluster, which constituted a replication, totaling 28 replications per treatment. The data were collected in April 2018, in a rural property in the municipality of Cacoal, state of Rondônia, Brazil (11º21’50’’S, 61º20’10’’W, and altitude of 238 m). The soil organic matter, pH, P, K, Ca, Mg, Al, H+Al, base saturation, and basal respiration were determined. The soil under SCC had higher Ca content, pH, and base saturation, and lower potential acidity (H+Al) and Al content than that under FCC. The litterfall on the soil under FCC presented higher N and Mg contents. The soil basal respiration increased in the first 5 cm depth in the treatment with SCC.