Heavy Metals and Microbial Activity in Alluvial Soils Affected by Different Land-Uses

Abstract

Soils must receive maximum protection to assure sustainable agriculture and quality food production. Heavy metals tend to accumulate in the soil rather than decompose and at a certain limit of their content, toxic consequences for living organisms occur. This research was conducted to survey the contamination status of Cd, Cr, Ni, and Pb and microbial activity in soils affected by long-term sugarcane monoculture in Upper Egypt. The rise of diacetate fluorescein hydrolysis (FDA) ranged from 86.25 to 201.25 mg kg -1 soil•h -1 in sugarcane monoculture fields, while the increase under crop rotation fields showed higher and significant values ranged from 207.25 to 266.67 mg kg -1 soil•h -1 . In this study, generally soil microbial biomass and enzymatic activity was usually and significantly higher under crop rotation than sugarcane monoculture. The highest potential ecological risks were found in soils under long-term irrigated sugarcane monoculture, while being moderate for crop rotation. Under both sugarcane monoculture and crop rotation farming systems, cadmium Cd was observed to be the urgency pollutant with the highest degree of contamination even though Cd had the lowest average concentration (Cd 27.03 mg kg -1 ) in sugarcane monoculture fields, and Cd (10.46 mg kg -1 ) in crop rotation. In view of the impacts of these potentially toxic elements of cadmium (Cd), chromium (Cr), nickel (Ni) and lead (Pb), on the ecological system and public health, the introduction of new management practices in sugarcane monoculture fields are essential to protect the environment and to achieve future sustainability in sugarcane production in Upper Egypt.

Assessment of Soil Contamination Using GIS and Multi-Variate Analysis: A Case Study in El-Minia Governorate, Egypt

“…These findings are consistent with similar studies in the Nile valley and Delta [14,23,51]. On the other hand, southern parts of the study area were characterized by low concentrations of most of the selected elements except for Co, as its concentrations were significantly high, which may be associated with the human activities and the agricultural management practices in these areas in terms of fertilization use [30,46].…”

“…A higher correlation was found between Cd and Cr. The obtained results agreed with other investigations in the Abo-Korkas district [30,44]. All means of the studied heavy metals were higher than the chemical composition of the upper continental crust according to Taylor and Mclennan, 1995 [35]; and the natural concentration of heavy metals in rocks according to Bradl, 2005 [45].…”

“…All means of the studied heavy metals were higher than the chemical composition of the upper continental crust according to Taylor and Mclennan, 1995 [35]; and the natural concentration of heavy metals in rocks according to Bradl, 2005 [45]. The wide range of heavy metal concentrations in the study area is related to the great diversity in the quantities used of chemical and organic fertilizers by farmers [30,46], in addition to the use of polluted water from "El-Moheet drainage" in the irrigation process [44].…”

“…The freshwater from the Nile is the main irrigation source in the agricultural sector. The Egyptian farmer usually depends on his personal experience in determining the quantities of added chemical and organic fertilizers without considering the recommendations issued by the responsible authorities [30,31]. The farming system in the study area is dependent on a surface irrigation system using freshwater and groundwater.…”

“…fertilizers without considering the recommendations issued by the responsible authorities [30,31]. The farming system in the study area is dependent on a surface irrigation system using freshwater and groundwater.…”