Abstract
In order to explore how the land treatment of rural sewage affects the soil environment and the flue-cured tobacco quality, the pretreated sewage collected from rural areas of south China were directly discharged to the experimental fields and the microbial number, enzymatic activities of soils with different distance away from the outlet and different depth were observed; besides, the sewage were diluted to different proportions and applied for the cultivations of flue-cured tobacco, afterwards, the flue-cured tobacco leaves at maturity were harvested for the quality evaluation and the Principle Component Analysis (<em>PCA</em>) method was adopted to select the best dilution proportion (treatment) based on the comprehensive analysis of the quality of tobacco leaves under different treatments. Results showed that: The sewage treatment had little effect on surface soil microbial number, but which significantly increased the number of bacteria, fungus and actinomyce in soils of 20~40 cm and 40~60 cm layer. At the same time, the sewage treatment significantly increased the soil enzymatic activity including the urease activity, catalase activity and polyphenol oxidase activity at all measuring points. Known from the analysis of flue-cured tobacco leaves, treatments with higher sewage proportion obviously increased the content of nicotine, total N and potassium in flue-cured tobacco leaves, but which decreased the content of reducing sugar. According to the calculations of <em>PCA</em> model, the quality sequence from excellent to inferior could be ordered as: T2>T1>T3>T4>CK, therefore, for flue-cured tobaccos, T2 was more conductive for equilibrium absorption of nutrients compared with other treatments.
Highlights
The rapid growth of population, the indiscriminate discharge of modern industrial wastewater, the generating of municipal waste and the spraying of rural pesticide had already caused the shortage of freshwater resources, some of the polluted waters could not be used by mankind, according to statistics, there were more than 2000 kind of contaminants found in these polluted waters, leading to a serious environmental problem which threaten the human survival, the treatment of wastewaters had been a hot topic for researches from all over the world (Hamzeh et al, 2011; Varol, 2013; Zhou et al, 2013)
In the south of China, sewage was an important component of rural wastes and the land treatment of rural sewage was a kind of wastewater treatment method with lower cost and smaller occupation space
The soil microorganisms and the soil enzyme almost participated in the entire chemical or biochemical process of soil ecosystem, the development of microorganisms and the activities of enzyme in soils reflected the soil health directly and which were important indexes to evaluate the soil quality (Castro et al, 2013; Gruyer et al, 2013; Jang et al, 2013)
Summary
The rapid growth of population, the indiscriminate discharge of modern industrial wastewater, the generating of municipal waste and the spraying of rural pesticide had already caused the shortage of freshwater resources, some of the polluted waters could not be used by mankind, according to statistics, there were more than 2000 kind of contaminants found in these polluted waters, leading to a serious environmental problem which threaten the human survival, the treatment of wastewaters had been a hot topic for researches from all over the world (Hamzeh et al, 2011; Varol, 2013; Zhou et al, 2013). The effects of land treatment for rural sewage on the soil microorganisms and the soil enzyme activities at different measuring points were observed and the sewage were diluted to different
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
