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Ning Z, Wang S, Guo C, Zhang M. The impact of environmental factors on the transport and survival of pathogens in agricultural soils from karst areas of Yunnan province, China: Laboratory column simulated leaching experiments. Front Microbiol 2023; 14:1143900. [PMID: 37007467 PMCID: PMC10060967 DOI: 10.3389/fmicb.2023.1143900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/22/2023] [Indexed: 03/18/2023] Open
Abstract
IntroductionGroundwater is considered the best candidate for drinking water supply in the karst area. The groundwater water resources, however, are vulnerable to pathogenic microorganism contamination because of the typically thin soil layers overlying aquifers and the high permeability of the aquifer host rock, resulting in short residence times and low natural attenuation capacities. Until now, little attention has been paid to the critical environmental factors affecting the pathogenic microorganism contamination in soil-groundwater systems in the karst area.MethodsIn the study, orthogonality column experiments with controlling ambient temperatures, pH values of inlet water, and soil porosities were carried out to investigate the transport and lifespan of pathogenic microorganisms in the leachate of agricultural soils in the karst area of Yunnan province, China. The pathogenic indicators, i.e., total bacteria count (TBC) and total coliforms count (TCC), and hydrochemical parameters, i.e., pH and permanganate index (CODMn) in the leaching water, were systematically monitored.Results and DiscussionThe results showed that bacteria including coliforms can survive for prolonged periods of time in karst soils. The soils overlying the karst rocks were unable to impede the bacteria from seeping into the groundwater. The soils, in turn, likely served as both reservoirs and incubators for pathogenic bacteria. The ambient temperature was the most predominant influential factor affecting both TBC and TCC. The bacteria concentrations were proportional to the temperature in the leachate. Therefore, more attention should be paid to temperature variations in protecting the water supply, particularly in the high-temperature period, such as during the summer months.
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Affiliation(s)
- Zhuo Ning
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, China
- Key Laboratory of Groundwater Remediation of Hebei Province and China Geological Survey, Zhengding, China
| | - Shuaiwei Wang
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, China
- *Correspondence: Shuaiwei Wang,
| | - Caijuan Guo
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, China
| | - Min Zhang
- Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, China
- Key Laboratory of Groundwater Remediation of Hebei Province and China Geological Survey, Zhengding, China
- Min Zhang,
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Wen L, Li D, Xiao K, Tang H, Xiao X, Li C. Difference in total N and its aggregate-associated N following cropland restoration in a karst region, Southwest China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:50759-50771. [PMID: 36800093 DOI: 10.1007/s11356-023-25826-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 02/05/2023] [Indexed: 02/18/2023]
Abstract
Cropland conversion has been cited as one of the most effective measures for increasing soil nitrogen pool in karst degraded regions. However, it is still unclear how N associated with aggregate patterns and their contribution to net soil N accumulation after cropland conversion. The experiment included four treatments with one control and three restoration strategies, that is, maize-soybean rotation cultivation (the control), sugarcane, mulberry, and forage grass cultivation. Soil samples were selected to determine the soil aggregate amount and its associated N content and stock across 0-30 cm soil layer. Macro-aggregate (> 2 mm) was the predominant aggregate fraction in all cropland use types and had the largest N stock. Forage grass cultivation substantially increased N stocks in bulk soil and aggregate fractions. The N contents and stocks associated with aggregate were shown to be positively correlated with bulk soil N stocks. Furthermore, the increase in N stock in forage grass soil was largely caused by an increase in N stock within macro-aggregates (> 2 mm), which is further attributed to the increased N content within macro-aggregates. Overall, forage grass cultivation replaced maize-soybean cultivation which was proposed as an ecological restoration model to improve soil N sequestration capacity due to its function in increasing the N stock of aggregate in the karst degraded region of Southwest China.
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Affiliation(s)
- Li Wen
- Hunan Soil and Fertilizer Institute, 730Yuanda 2Nd Road, Changsha, 410125, Hunan, China.
| | - Dejun Li
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huangjiang, 547100, Guangxi, China
| | - Kongcao Xiao
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huangjiang, 547100, Guangxi, China
| | - Haiming Tang
- Hunan Soil and Fertilizer Institute, 730Yuanda 2Nd Road, Changsha, 410125, Hunan, China
| | - Xiaoping Xiao
- Hunan Soil and Fertilizer Institute, 730Yuanda 2Nd Road, Changsha, 410125, Hunan, China
| | - Chao Li
- Hunan Soil and Fertilizer Institute, 730Yuanda 2Nd Road, Changsha, 410125, Hunan, China
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