Efeito da água produzida nos atributos microbiológicos do solo sob cultivo de plantas no semiárido

Abstract

Environmental degradation and water restrictions in semiarid regions undertake agricultural production and reinforce the need for water management to maintain crop productivity. Researchers suggest the use of produced water, obtained in the process of oil extraction, as alternative of irrigation, especially in areas close to oil fields with water scarcity. However, there have been limitations on application this water due to the common presence of salts, metals and toxic compounds that may to impact negatively the soil. This study aimed to evaluate soil microbiological attributes in areas under cultivation of bioenergy plants irrigated with different waters (underground and produced water) and compare them with controls uncultivated and native vegetation soils. Experiments with species of sunflower and castor beans irrigated with water collected from underground (AC), produced water treated with simple filtering (APF), produced water treated by reverse osmosis (APO) and uncultivated soil (NCNI) were conducted on Belém farm, Aracati, Ceará state, Brazil. The surface layer of soil (0-10 cm) was collected in the ranks of pre-planting and planting during the growing and flowering plants, and evaluated by the population density of filamentous fungi and cultivable bacterias, organic carbon (COT), microbial biomass carbon (CBM), basal respiration (RB), metabolic quotient (qCO2) and enzyme activity. The results of this study revealed that treatment with APF and APO affect differently soil attributes, with the first positively changing the number of microorganisms and enzyme activity, while the second reduces dehydrogenase and populations of fungi and bacterias of soil. However, treatments with AC and APF had similar effects on indicators studied. Differences were not found between treatments when analyzed soil parameters of management COT, CBM, RB and qCO2 in first crop cycle. The values of most microbiological indicators evaluated were similar in native forest and areas cultivated with bionergy plants irrigated.