Revista Engenharia na Agricultura - REVENG

Effects of initial pressure and sample and air cylinder dimensions on determination of soil air permeability

Anderson Fialho Baleeiro — 2025-02-27

The intrinsic soil air permeability (Kair), defined as the capacity of soil pores to conduct air, is an important soil attribute, as it identifies changes in pore spaces. This study aimed to evaluate the influence of initial gauge pressure, permeameter air cylinder volume, and sample volume on the Kair measurement. Samples of an Oxisol were collected at a depth of 0–0.2 layer and stored in a pot. The experimental design was completely randomized in a 4x3x2 factorial scheme, characterized by four different initial gauge pressures (500, 1000, 1500, and 2000 Pa), three different permeameter cylinder volumes (0.008, 0.0124, and 0.031 m3), and two sample volumes (100 and 270 cm3). The assessment was performed under two soil density conditions in pots (1.334 and 1.421 Mg m?3). Kair showed no changes due to the different sample volumes, but a different behavior was observed for the two soil density conditions. Increasing the permeameter air cylinder volume promoted an increase in the Kair estimate. Kair was lower for the initial pressure evaluated with 2000 Pa.

Evaluation of the red rice imbibition time under different fertilizing sources

Gabriel Gustavo Tavares Nunes — 2025-03-18

Red rice is considered the predominant weed species in rice fields, causing significant economic losses to producers. The objective of this study was to evaluate the behavior of red rice seeds during the soaking of seeds in water, as well as the development of plants under two fertilization sources (NPK and complete nutrient solution). Seeds were subjected to different soaking durations in water: 0, 10, 20, 30, 40, 50, and 60 minutes. After four days of germination, the seedlings were divided into two treatment groups: (i) plants fertilized with NPK and (ii) plants fertilized with complete nutrient solution. The experiment was conducted in a completely randomized design, evaluating the variables: germination, number of leaves, plant height and dry matter accumulation. A significant increase in germination percentage, number of leaves, plant height and dry matter accumulation in both the aerial part and roots was observed with longer seed soaking durations. This effect was more expressive in red rice plants fertilized with the complete nutritive solution. Thus, we conclude that this fertilizer source enhances the competitive ability of this weed species against cultivated rice.

Multivariate analysis of latosol attributes in the amazon-caatinga transition zone under an agropastoral system

Ismênia Ribeiro de Oliveira — 2025-04-02

This study aims to analyze the dynamic relationship between the physicochemical attributes of a Yellow Dystrophic Latosol, which a particular focus on their direct and indirect influences on soil electrical conductivity. Soil samples were collected from 50 georeferenced points within the municipality of Brejo – MA, Brazil, to evaluate these interactions using multivariate stastistical approaches. The path analysis process was conducted using the GENES software, a statistical tool essential for estimate linear correlation values and decomposing the data. The evaluated soil attributes included electrical conductivity, altitude, humidity, soil density, porosity, organic matter, pH, clay, silt, total sand, very coarse sand, coarse sand, medium sand, fine sand, very fine sand, aggregates larger than 2.00 mm³, aggregates larger than 1.00 mm³, aggregates larger than 1.00 mm³, aggregates larger than 0.10 mm³, weighted mean diameter, and mean internal diameter. The approach was adopted due to the high occurrence of multicollinearity, which can lead to interpretative misunderstanding. For this purpose, data decomposition was performed, using electrical conductivity as primary variable - to mitigate the mutual influence among soil attributes. The analysis revealed that pH is the most influential attribute in determining the electrical conductivity of the studied Latosol.