Assessment of Physicochemical Properties and Heavy Metal Content of Floriculture Soil in Amhara Region of Northwest Ethiopia

Abstract

Floriculture is a new and rapidly expanding sector in Ethiopia that aids economic growth but has also come under blame for pollution of the surrounding soil. The purpose of this study was to assess the soil physicochemical properties and heavy metal contents in floriculture in the Amhara Region of Northwest Ethiopia. Soil samples were collected from seven different greenhouses (2ABC, 4DEF, 5ABC, 7DEF, 8ABC, 9DEF, and 11DEF), and a control soil sample was taken on the 15-cm depth from a nearby agricultural area. They were analyzed for soil physicochemical parameters and heavy metal compositions. Soil texture showed a significant difference between the soils sampled from the greenhouses and the control group. The highest average clay, silt, and sand contents were recorded in the control group, 4DEF, and 9DEF, respectively. The lower clay content was at 9 DEF, silt at 11 DEF, and sand in the control group. Clay was positively correlated to soil pH (<i>r</i> = 0.66) and TN (<i>r</i> = 0.38) but showed significant negative correlation with the sand fraction (<i>r</i> = -0.96). The average bulk density (BD) values of the soils from the greenhouses were within acceptable ranges; however, the mean BD value of 7DEF was relatively highest (1.34 g/cm³). There were significant (<i>P</i> < 0.05) changes in soil pH and electrical conductivity, with pH values ranging from 5.8 to 7.17 and EC from 0.08 to 1.72 mScm^-1. Soil organic carbon, available phosphorus, total nitrogen, and carbon-to-nitrogen ratio of the soil samples from the greenhouses and the control group were significantly different. There were also significant differences in soil exchangeable aluminum and acidity between greenhouse soil samples and the control group. Soil contents of some of the heavy metals (Pb, Cd, Mn, and Cu) in the floriculture soil were above the permissible limits, while Cr, Zn, and Ni contents were below. The soil in floriculture showed low quality compared to the control group and international standards, indicating the need for improved soil quality management. This study recommends reducing agrochemical use, increasing bio-fertilizers, using botanicals, and transitioning to organic farming. Further studies are needed to assess soil microbial diversity and abundance for soil fixation.