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Title (Primary) Spatial control of microbial pesticide degradation in soil: A model-based scenario analysis
Author Schwarz, E.; Khurana, S.; Chakrawal, A.; Chavez Rodriguez, L.; Wirsching, J.; Streck, T.; Manzoni, S.; Thullner, M.; Pagel, H.
Journal Environmental Science & Technology
Year 2022
Department UMB
Volume 56
Issue 20
Page From 14427
Page To 14438
Language englisch
Topic T7 Bioeconomy
Keywords small-scale heterogeneity; pesticide fate; reactive transport modeling; scale transition theory; spatial moment analysis
Abstract Microbial pesticide degraders are heterogeneously distributed in soil. Their spatial aggregation at the millimeter scale reduces the frequency of degrader–pesticide encounter and can introduce transport limitations to pesticide degradation. We simulated reactive pesticide transport in soil to investigate the fate of the widely used herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in response to differently aggregated distributions of degrading microbes. Four scenarios were defined covering millimeter scale heterogeneity from homogeneous (pseudo-1D) to extremely heterogeneous degrader distributions and two precipitation scenarios with either continuous light rain or heavy rain events. Leaching from subsoils did not occur in any scenario. Within the topsoil, increasing spatial heterogeneity of microbial degraders reduced macroscopic degradation rates, increased MCPA leaching, and prolonged the persistence of residual MCPA. In heterogeneous scenarios, pesticide degradation was limited by the spatial separation of degrader and pesticide, which was quantified by the spatial covariance between MCPA and degraders. Heavy rain events temporarily lifted these transport constraints in heterogeneous scenarios and increased degradation rates. Our results indicate that the mild millimeter scale spatial heterogeneity of degraders typical for arable topsoil will have negligible consequences for the fate of MCPA, but strong clustering of degraders can delay pesticide degradation.
Persistent UFZ Identifier
Schwarz, E., Khurana, S., Chakrawal, A., Chavez Rodriguez, L., Wirsching, J., Streck, T., Manzoni, S., Thullner, M., Pagel, H. (2022):
Spatial control of microbial pesticide degradation in soil: A model-based scenario analysis
Environ. Sci. Technol. 56 (20), 14427 - 14438