Soil Mineral Backfills and Radionuclide Retention

Author(s):  
James L. Krumhansl ◽  
Patrick V. Brady ◽  
Peng-Chu Zhang
Keyword(s):  
2019 ◽  
Author(s):  
Prasanth Babu Ganta ◽  
Oliver Kühn ◽  
Ashour Ahmed

The phosphorus (P) immobilization and thus its availability for plants are mainly affected by the strong interaction of phosphates with soil components especially soil mineral surfaces. Related reactions have been studied extensively via sorption experiments especially by carrying out adsorption of ortho-phosphate onto Fe-oxide surfaces. But a molecular-level understanding for the P-binding mechanisms at the mineral-water interface is still lacking, especially for forest eco-systems. Therefore, the current contribution provides an investigation of the molecular binding mechanisms for two abundant phosphates in forest soils, inositol hexaphosphate (IHP) and glycerolphosphate (GP), at the diaspore mineral surface. Here a hybrid electrostatic embedding quantum mechanics/molecular mechanics (QM/MM) based molecular dynamics simulation has been applied to explore the diaspore-IHP/GP-water interactions. The results provide evidence for the formation of different P-diaspore binding motifs involving monodentate (M) and bidentate (B) for GP and two (2M) as well as three (3M) monodentate for IHP. The interaction energy results indicated the abundance of the GP B motif compared to the M one. The IHP 3M motif has a higher total interaction energy compared to its 2M motif, but exhibits a lower interaction energy per bond. Compared to GP, IHP exhibited stronger interaction with the surface as well as with water. Water was found to play an important role in controlling these diaspore-IHP/GP-water interactions. The interfacial water molecules form moderately strong H-bonds (HBs) with GP and IHP as well as with the diaspore surface. For all the diaspore-IHP/GP-water complexes, the interaction of water with diaspore exceeds that with the studied phosphates. Furthermore, some water molecules form covalent bonds with diaspore Al atoms while others dissociate at the surface to protons and hydroxyl groups leading to proton transfer processes. Finally, the current results confirm previous experimental conclusions indicating the importance of the number of phosphate groups, HBs, and proton transfers in controlling the P-binding at soil mineral surfaces.


Geoderma ◽  
2018 ◽  
Vol 326 ◽  
pp. 9-21 ◽  
Author(s):  
Masuda Akter ◽  
Heleen Deroo ◽  
Eddy De Grave ◽  
Toon Van Alboom ◽  
Mohammed Abdul Kader ◽  
...  

1999 ◽  
Vol 50 (2) ◽  
pp. 115-125 ◽  
Author(s):  
Maria Stenberg ◽  
Helena Aronsson ◽  
Börje Lindén ◽  
Tomas Rydberg ◽  
Arne Gustafson

1996 ◽  
Vol 32 (3) ◽  
pp. 339-349 ◽  
Author(s):  
M. Pala ◽  
A. Matar ◽  
A. Mazid

SUMMARYA series of researcher-managed wheat fertilizer trials was conducted on representative farmers' fields across northwest Syria between 1986 and 1990. Wheat grain and straw yields were strongly correlated with seasonal (October-May) rainfall, almost irrespective of soil fertility, crop sequence or fertilizer rate, with a highly significant response to nitrogen fertilizer which increased with increasing rainfall and decreasing initial soil mineral-nitrogen values. These results were summarized in regression equations which express yield in terms of fertilizer rates, seasonal rainfall and their interactions. The equations with applied nitrogen and seasonal rainfall were the most appropriate for determining fertilizer needs. Economic analysis indicated that all fertilizer treatment rates were profitable under existing price conditions and that fertilizer use would still be beneficial for a nitrogen price up to three times higher than that of the price of grain (weight for weight) with a seasonal rainfall of 250 mm, and up to six times higher with a seasonal rainfall of 450 mm.


2021 ◽  
Author(s):  
Na Li ◽  
Xinfeng Dong ◽  
Fuping Gan ◽  
Zhanchun Zou

2017 ◽  
Vol 21 (1) ◽  
pp. 1
Author(s):  
NI KADEK WIWIK SINTA DEWI ◽  
IDA BAGUS GEDE DARMAYASA ◽  
I KETUT SUNDRA

In Indonesia agriculture practice often used the large scale pesticide application such as insecticide, herbicide, and fungicide. The wide use of toxic pesticide has created numerous problem in increasing environtmental hazard to human and to other animals. Many of soil bacteria had important role to degrading chemical compounds into simpler compounds as a bioremediation agent. The aim of this study was to screen the Chlorantraniliprole tolerant bacteria using soil mineral medium with Prevathon pesticide addition, also teo identificate the species of bacteria. This research was conducted at Microbiology Laboratory, Faculty of Mathematics and Natural Sciences, Udayana University. The research was done in three analysis, (1) bacteria test on Prevathon pesticide addition to mineral medium treatment, (2) characterization of bacteria, (3) Identification of pesticide tolerant bacteria with BD BBL Crystal Enteric/Non FermenterID Kit. The results showed that mineral medium with the addition of pesticides Prevathon treatment able to provide a significant different effect on the enrichment stage 1, stage 2 and stage 3 (P<0.05), there was 5 isolates pesticide tolerant bacteria that isolated from Baturiti Tabanan cultivated soil that was BSP 1, BSP 2, BSP 3 known as gram negative bacteria, and BSP 4, BSP 5 known as Gram positive bacteria, pesticide tolerant bacteria identified as Serratia marcescens which is a Gram negative bacteria group and may cause pathogenic.


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