Migration behavior of benzobicyclon hydrolysate and associated influencing factors in different agricultural soils
Abstract. Benzobicyclon is a triketone pro-herbicide that needs to be hydrolyzed to form an active compound benzobicyclon hydrolysate (BH). This study aimed to investigate the migration behavior of BH in different types of agricultural soil and the associated influencing factors. Soil thin-layer chromatography and column leaching tests were used to study the migration behavior of BH in these soils. Based on the mobility retention factor (Rf = 0.34–0.90), the mobility of BH in thin soil layers was ranked in the order Lixisols > Anthrosols > Ferralsols > Phaeozems. The Rf value of BH was linearly positively correlated with soil sand content and pH, and negatively correlated with other physical and chemical properties of soil. BH was difficult to leach in Phaeozems, less difficult to leach in Ferralsols, and easy to leach in Anthrosols and Lixisols. Increasing the BH dosage and rainfall amount or adding humic acid and anionic (dodecyl benzene sulfonic acid) or nonionic (Tween-80) surfactant blocked BH migration in soil columns. In contrast, increasing the leaching solution pH and adding cationic surfactant (cetyl trimethyl ammonium bromide) promoted BH migration in soil columns.BH application has a low risk of groundwater pollution in Phaeozems and Ferralsols, but poses a potential threat to groundwater in Anthrosols and Lixisols.
This preprint has been withdrawn.
Lang Liu et al.
Lang Liu et al.
Lang Liu et al.
Viewed (geographical distribution)
Several grammatical and syntax issues are present within the manuscript, as well as many incorrect statements (e.g. mentioning non-significant results in the abstract and saying an increase in BH dosage and rainfall amount blocked BH migration in the abstract). These issues have not been outlined, however, in light of two major issues I have with the project design which makes me sceptical of the results and if cannot be fixed is reason to reject the manuscript.
1) The main conclusion of the manuscript is the ranking of four soil types in regards to the mobility of BH, and their susceptibility to leaching BH. However, only a single sample has been taken for each soil type and as such, there is no measure of variability within the soil types that would be necessary to make sweeping statements about the soil type as a population. Due to this, the conclusions like:
"Based on the mobility retention factor (Rf = 0.34–0.90), the mobility of BH in thin soil layers was ranked in the order Lixisols > Anthrosols > Ferralsols > Phaeozems"
would need to be changed to:
"Based on the mobility retention factor (Rf = 0.34–0.90), the mobility of BH in thin soil layers was ranked in the order S4 > S3 > S1 > S2"
as you can only justifiably say that there is a difference between the samples as opposed to soil types.
2) The method indicates that 4 cm diameter by 30 cm cores were packed with 600 to 700 g of air-dried soil. A core packed with 600 g of soil would have an air-dried bulk density of 1.59 g/cm^3, while a core packed with 700 g would have an air-dried bulk density of 1.86 g/cm^3. Thus, cores have a potential variation of 15-17% in air-dried bulk density which would have significant impacts on the porosity of the cores, the dynamics of water and thus the dynamics of the solute. This issue in the method would make me sceptical of any of the results from the leaching experiments.
-Additional questions about the method were if the soil was uniformly dried? Was the water content of the soil at packing determined? Because variation in moisture content at packing can introduce significant artefacts especially when dealing with variable soils.