Method for the physical characterization of substrates using centrifugation

The characterization of substrate properties supports the correct choice of components and directs management decisions in container cultivation. There are several systems of analysis, however, the routine procedures to determine the water retention curve (WRC) are time consuming and inaccurate. This study proposed a reproducible, less time-consuming, and easy to perform method for physical characterization of substrates. We used Sphagnum peat, coconut powder, carbonized rice husk, expanded vermiculite, and expanded clay in isolation. The WRC was obtained at tensions 0, 10, 50, and 100 hPa using the method of Büchner funnel, the European standard (CEN-EN13041), and by the centrifugation method of samples. In centrifugation, tensions were simulated by combining the angular velocity, sample height, and radius measured from the sample outermost point to the central point of the centrifuge. Three rotations were applied (230; 520 and 730 rpm), testing the centrifugation time for each tension and then the volumetric water content was compared between the methods. The results showed a positive correlation (p < 0.001) between the centrifugation and standard methods, considering that the centrifugation time required for moisture stabilization varied according to the material analyzed and the tension applied. However, the time required to obtain a report was reduced by half. Sample centrifugation is a promising method, ensuring that the tensile force actually acts on the entire sample to determine the water retention curve of the substrate also reducing the duration of the analyses.

Qualitative and quantitative evaluation of the urban trees of public squares and routes / Avaliação quali-quantitativa da arborização urbana de praças e vias públicas

The urban afforestation is important for the life quality of the populations, however, good planning is required, in order to avoid problems that cause interference with urban elements and biological invasion. This study aimed to perform a quantitative and qualitative survey of the urban trees in squares and main routes of Tenente Portela, RS. Five squares and the six busiest routes in the municipality were inventoried through a census, by analyzing every individual shrub and tree. A total of 743 individual plants belonging to 67 species and 27 botanical families were found, with Ligustrum lucidum being the most abundant species (20.46%). The most abundant family was Bignoniaceae (27%). The mean height and circumference at breast height of the species were, respectively, 5.95 m and 67 cm. Regarding interference, 30% of individuals had canopies interfering with pedestrian or vehicles passages, and 33.8% of trees were damaging the sidewalks due to root outcrops. The general condition of the 455 plants was considered good and 50% of the total was growing under concrete pavement. Although major problems related to the quality of individual plants were not detected, a better planning of afforestation in urban area is necessary and it is expected that the results observed in this study can assist the municipal government in this planning.

A arborização urbana é importante para a qualidade de vida das populações, porém deve ser bem planejada, a fim de evitar problemas que causem interferência nos elementos urbanos e invasão biológica. Este trabalho teve como objetivo realizar o levantamento quantitativo e qualitativo da arborização urbana das praças e principais vias no município de Tenente Portela, RS. Foram inventariadas as cinco praças existentes no município e as seis vias mais movimentadas, por meio de um censo, analisandose todos os indivíduos arbustivo-arbóreos. Foram encontrados 743 indivíduos distribuídos em 67 espécies e 27 famílias botânicas, sendo Ligustrum lucidum a espécie mais abundante (20,46%). Entre as famílias, destacou-se Bignoniaceae (27%). A média da altura e da circunferência na altura do peito das espécies foram, respectivamente, de 5,95 m e 67 cm. Em relação às interferências, 30% dos indivíduos tinham a copa interferindo na passagem de pedestres e/ou, veículos, e 33,8% dos indivíduos estavam prejudicando as calçadas devido ao afloramento de raízes. O estado geral dos 455 indivíduos incluídos no inventário era bom e 50% do total estavam plantadas sob o pavimento de concreto. Embora não tenham sido detectados grandes problemas relacionados à qualidade dos indivíduos, é necessário o melhor planejamento da arborização e espera-se que os resultados possam auxiliar o poder público neste planejamento.

Qualitative and quantitative evaluation of the urban trees of public squares and routes / Avaliação quali-quantitativa da arborização urbana de praças e vias públicas

The urban afforestation is important for the life quality of the populations, however, good planning is required, in order to avoid problems that cause interference with urban elements and biological invasion. This study aimed to perform a quantitative and qualitative survey of the urban trees in squares and main routes of Tenente Portela, RS. Five squares and the six busiest routes in the municipality were inventoried through a census, by analyzing every individual shrub and tree. A total of 743 individual plants belonging to 67 species and 27 botanical families were found, with Ligustrum lucidum being the most abundant species (20.46%). The most abundant family was Bignoniaceae (27%). The mean height and circumference at breast height of the species were, respectively, 5.95 m and 67 cm. Regarding interference, 30% of individuals had canopies interfering with pedestrian or vehicles passages, and 33.8% of trees were damaging the sidewalks due to root outcrops. The general condition of the 455 plants was considered good and 50% of the total was growing under concrete pavement. Although major problems related to the quality of individual plants were not detected, a better planning of afforestation in urban area is necessary and it is expected that the results observed in this study can assist the municipal government in this planning.(AU)

A arborização urbana é importante para a qualidade de vida das populações, porém deve ser bem planejada, a fim de evitar problemas que causem interferência nos elementos urbanos e invasão biológica. Este trabalho teve como objetivo realizar o levantamento quantitativo e qualitativo da arborização urbana das praças e principais vias no município de Tenente Portela, RS. Foram inventariadas as cinco praças existentes no município e as seis vias mais movimentadas, por meio de um censo, analisandose todos os indivíduos arbustivo-arbóreos. Foram encontrados 743 indivíduos distribuídos em 67 espécies e 27 famílias botânicas, sendo Ligustrum lucidum a espécie mais abundante (20,46%). Entre as famílias, destacou-se Bignoniaceae (27%). A média da altura e da circunferência na altura do peito das espécies foram, respectivamente, de 5,95 m e 67 cm. Em relação às interferências, 30% dos indivíduos tinham a copa interferindo na passagem de pedestres e/ou, veículos, e 33,8% dos indivíduos estavam prejudicando as calçadas devido ao afloramento de raízes. O estado geral dos 455 indivíduos incluídos no inventário era bom e 50% do total estavam plantadas sob o pavimento de concreto. Embora não tenham sido detectados grandes problemas relacionados à qualidade dos indivíduos, é necessário o melhor planejamento da arborização e espera-se que os resultados possam auxiliar o poder público neste planejamento.(AU)