Environmental fate of bensulfuron-methyl and MCPA in aerobic and anaerobic rice-cropping systems

• Published in: Journal of environmental management Vol. 237; pp. 44 - 53
• Main Authors: López-Piñeiro, Antonio, Peña, David, Albarrán, Ángel, Sánchez-Llerena, Javier, Becerra, Daniel, Fernández, Damián, Gómez, Soraya
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2019
• Subjects: Aerobic and anaerobic rice; Bensulfuron; Leaching; MCPA; Persistence; Sorption; Persistence; Sorption; MCPA; Bensulfuron; Leaching; Aerobic and anaerobic rice
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2019.02.058

Bensulfuron-methyl (BM) and 4-chloro-2-methylphenoxyacetic acid (MCPA) are herbicides widely used in rice agroecosystems, and are commonly found in their environments, especially in water resources. The objective of this study was to evaluate the sorption-desorption, leaching, and dissipation of BM and MCPA under aerobic and anaerobic rice cropping conditions. For this purpose, a three-year field experiment was conducted in SW Spain using four management systems: aerobic with sprinkler irrigation and tillage (ST), sprinkler irrigation and no-tillage (SNT), long-term sprinkler irrigation and no-tillage (SNTLT), and anaerobic with flooding and tillage (FT). At the end of the experiment, the partition coefficients (Kd-values) in ST were (2.7, 3.1, and 3.9) and (1.2, 1.5, and 1.9) times significantly lower than the values in {SNT, SNTLT, and FT} for BM and MCPA, respectively. Greater sorption was related to lower values of soil pH for both herbicides and to higher contents in humic acids for BM and fulvic acids for MCPA. The persistence was much longer for BM (t1/2 = 26.9–52.1 days) than for MCPA (t1/2 = 1.54–21.1 days) in all management systems, and both herbicides' dissipation rates were generally greater under aerobic than under anaerobic conditions. The mobility of MCPA was much greater than that of BM. Compared with SNT and SNTLT, leaching losses of the applied BM were greater by 51% for ST, and of the applied MCPA by 55% and 99% for ST and FT, respectively. Therefore, only aerobic rice production with no-tillage in the short- or long-terms could be considered as alternative management strategies with which to reduce water contamination by BM and MCPA in rice-growing environments. •Aerobic rice production modifies soil properties leading to changes in MCPA and BM behaviour.•Soil pH, OC, and humified fractions were major factors contributing to behaviour of both herbicides.•MCPA and BM persistence was greater under aerobic than under anaerobic conditions.•Aerobic rice production under no-tillage reduced the risk of water contamination by MCPA.•Aerobic rice under tillage may increase the risk of water contamination by BM.