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Very little research has been done on the capillary rise in soil for agriculture and geotechnical engineering. The capillary rate rise of water in fine granular soil is one of the major challenges for rising experiments in vertical tubes, as the time required for the water to reach the maximum height of capillary rise can vary from 100 to 400 days. The present research aimed to validate a correlation curve for the capillary rise of a silt-clay soil of the Guabirotuba Geological Formation (Paraná, Brazil) as a function of the time of water rise. The control variables of the study were: compaction, water content, porosity, hydraulic conductivity, soil column height, and rate of capillary rise. Results were gathered by comparing the behavior of capillary rise using the analytical solutions developed by Terzaghi and Lu and Likos. On analysis of the results, it was concluded that the equation proposed by Terzaghi was the most suitable for the silt-clay soil of this study. [ABSTRACT FROM AUTHOR]

Summary: Accurate evaluation of metal bioavailability to hyperaccumulators is necessary for prediction of metal uptake and estimation of phytoextraction potential. Sedum plumbizincicola X.H. Guo et S.B. Zhou ex L.H. Wu (Crassulaceae), a hyperaccumulator of cadmium (Cd) and zinc (Zn), was grown in a pot experiment in 108 agricultural soils representing a wide range of typical Chinese soil types. The contribution of soil properties to Zn uptake was assessed quantitatively. Soil total Zn, soluble Zn, CaCl2‐extractable Zn and (DGT)‐extractable Zn concentrations (Zntotal, Znsoln, ZnCaCl2 and ZnDGT, respectively) were compared to predict shoot Zn concentration (Znshoot) using a piecewise equation. This showed a logarithmic increase with increasing Zntotal from 100–1000 mg kg−1 but plateaued outside this range. The optimum soil pH for Zn removal was ~ 5.5 and further acidification was unnecessary because Znshoot increased significantly with a decrease in pH from 7.5 to 5.5 and rarely changed at pH < 5.5. Sedum plumbizincicola grown in loamy or clay loam soils had larger Znshoot than in sandy or clay soils. The ZnCaCl2 was superior to other methods in estimating Zn bioavailability across all the data. At pH < 5.5, ZnCaCl2 showed much stronger correlation with Znshoot than Zntotal, Znsoln or ZnDGT. Piecewise equations (single linear regression equations at different intervals of soil properties) versus Zntotal and ZnCaCl2 at different pH ranges considerably increased the accuracy of prediction of Znshoot compared with the global equations derived from all data. Estimation of the potential of S. plumbizincicola for Zn phytoextraction in the field indicated that it is feasible to decontaminate acid‐polluted soils with Zntotal ≤ 500 mg kg−1 with S. plumbizincicola. Highlights: Zn bioavailability to hyperaccumulators needs to be estimated over a wide range of soil types.Piecewise equations considerably improved the prediction of shoot Zn concentration.CaCl2 extraction was more suitable than DGT for the estimation of Zn bioavailability.Decontamination with S. plumbizincicola is feasible for acid soils with Zntotal ≤ 500 mg kg−1. [ABSTRACT FROM AUTHOR]

Phenazines, a large group of nitrogen-containing heterocycles with promising bioactivities, can be widely used as medicines and pesticides. But phenazines also generate toxicity risks due to their non-selective DNA binding. The environmental fate of phenazines in soils is the key to assess their risks; however, hitherto, there have been very few related studies. Therefore in the present study, the degradation, adsorption and leaching behaviors of a typical natural phenazine—phenazine-1-carboxamide (PCN) in agricultural soils from three representative places in China with different physicochemical properties were, for the first time, systematically studied in laboratory simulation experiments. Our results indicated that the degradation of PCN in all the tested soils followed the first order kinetics, with half-lives ranging from 14.4 to 57.8 d under different conditions. Soil anaerobic microorganisms, organic matter content and pH conditions are important factors that regulating PCN degradation. The adsorption data of PCN were found to be well fitted using the Freundlich model, with the r2 values above 0.978. Freundlich adsorption coefficient K f of PCN ranged from 5.75 to 12.8 [(mg/kg)/(mg/L)1/n] in soils. The retention factor R f values ranged from 0.0833 to 0.354, which means that the mobility of PCN in the three types of soil is between immobile to moderately mobile. Our results demonstrate that PCN is easily degraded, has high adsorption affinity and low mobility in high organic matter content and clay soils, thus resulting in lower risks of contamination to groundwater systems. In contrast, it degraded slowly, has low adsorption affinity and moderately mobile in soils with low organic matter and clay content, therefore it has higher polluting potential to groundwater systems. Overall, these findings provide useful insights into the future evaluation of environmental as well as health risks of PCN. Image 1 • This is the first report of the environmental behaviors of phenazine in soils. • Anaerobic microorganisms were more important than the aerobic for degradation of PCN. • PCN easily degraded, has high adsorption and low mobility in high OMC and clay soils. • PCN in high OMC and clay soils has lower contamination risks to groundwater systems. PCN degraded slowly, has low adsorption affinity and moderate mobility in low OMC and clay content soils, therefore has higher polluting potential to groundwater systems. [ABSTRACT FROM AUTHOR]