Sepehrnia N, Memarianfard L, Moosavi A A, Bachmann J, Guggenberger G, Rezanezhad F
Department of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran; Institute of Soil Science, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany.
Department of Soil Science, College of Agriculture, Fars Science and Research Branch, Islamic Azad University, Marvdasht, 74715-181, Iran.
J Environ Manage. 2017 Oct 1;201:388-396. doi: 10.1016/j.jenvman.2017.07.009. Epub 2017 Jul 8.
A precise evaluation of bacteria transport and mathematical investigations are useful for best management practices in agroecosystems. In this study, using laboratory experiments and modeling approaches, we assess the transport of bacteria released from three types of manure (cow, sheep, and poultry) to find the importance of the common manures in agricultural activities in soil and water pollution. Thirty six intact soil columns with different textures (sandy, loamy, and silty clay loam) were sampled. Fecal coliform leaching from layers of the manures on the soil surface was conducted under steady-state saturated flow conditions at 20 °C for up to four Pore Volumes (PVs). Separate leaching experiments were conducted to obtain the initial concentrations of bacteria released from the manures (Co). Influent (Co) and effluent (C) bacteria concentrations were measured by the plate-count method and the normalized concentrations (C/C0) were plotted versus PV representing the breakthrough curves (BTCs). Transport parameters were predicted using the attachment/detachment model (two-kinetic site) in HYDRUS-1D. Simulations fitted well the experimental data (R = 0.50-0.96). The attachment, detachment, and straining coefficients of bacteria were more influenced by the soils treated with cow manure compared to the sheep and poultry manures. Influent curves of fecal coliforms from the manures (leached without soil) illustrated that the poultry manure had the highest potential to pollute the effluent water from the soils in term of concentration, but the BTCs and simulated data related to the treated soils illustrated that the physical shape of cow manure was more important to both straining and detachment of bacteria back into the soil solution. Detachment trends of bacteria were observed through loam and silty clay loam soils treated with cow manure compared to the cow manure enriched sandy soil. We conclude that management strategies must specifically minimize the effect of fecal coliform concentrations before field application, especially for the combination of poultry and cow manures, which has higher solubility and tailing behavior, respectively. Interestingly, the addition of sheep manure with all three soils had the lowest mobilization of bacteria. We also suggest studying the chemistry of soil solution affected by manures to present all relevant information which affect bacterial movement through soils during leaching.
对细菌迁移进行精确评估和开展数学研究，有助于农业生态系统最佳管理实践的实施。在本研究中，我们运用实验室实验和建模方法，评估了三种类型粪便（牛粪、羊粪和家禽粪便）中释放的细菌的迁移情况，以确定这些常见粪便在农业活动中对土壤和水污染的重要性。采集了36个具有不同质地（砂土、壤土和粉质粘壤土）的完整土柱。在20℃的稳态饱和流条件下，对土壤表面粪便层中的粪大肠菌群进行淋溶，淋溶量高达四个孔隙体积（PV）。进行了单独的淋溶实验，以获取粪便中释放的细菌的初始浓度（Co）。通过平板计数法测量进水（Co）和出水（C）细菌浓度，并绘制归一化浓度（C/C0）与代表穿透曲线（BTCs）的PV的关系图。使用HYDRUS - 1D中的吸附/解吸模型（双动力学位点）预测迁移参数。模拟结果与实验数据拟合良好（R = 0.50 - 0.96）。与羊粪和家禽粪便相比，牛粪处理的土壤对细菌的吸附、解吸和过滤系数影响更大。粪便（无土壤淋溶）中粪大肠菌群的进水曲线表明，就浓度而言，家禽粪便污染土壤出水的可能性最高，但与处理后土壤相关的BTCs和模拟数据表明，牛粪的物理形态对细菌过滤回土壤溶液和解吸更为重要。与富含牛粪的砂土相比，在经牛粪处理的壤土和粉质粘壤土中观察到了细菌的解吸趋势。我们得出结论，管理策略必须在田间施用前特别将粪大肠菌群浓度的影响降至最低，尤其是对于家禽粪便和牛粪的组合，它们分别具有较高的溶解度和拖尾行为。有趣的是，在所有三种土壤中添加羊粪时，细菌的迁移率最低。我们还建议研究受粪便影响的土壤溶液化学性质，以呈现所有影响淋溶过程中细菌在土壤中移动的相关信息。
