Behaviour of bentazon as influenced by water and tillage management in rice-growing conditions.
Bentazon is a widely used herbicide in rice agroecosystems that has commonly been found in water resources. To assess how tillage and water regimes affect sorption/desorption, dissipation and leaching of bentazon in Mediterranean rice-growing conditions, field experiments were carried out using tillage and flooding (TF), tillage and sprinkler irrigation (TS), no-tillage and sprinkler irrigation (NTS) and long-term no-tillage and sprinkler irrigation (NTS7). After 3 years, the Kdvalues in TS were 2.3, 1.6 and 1.7 times lower than the values in NTS7, NTS and TF respectively. Greater sorption of bentazon was related to higher contents in total organic carbon and, although to a lesser extent, in humic acids and dissolved organic carbon. The persistence of bentazon was significantly greater under anaerobic (half-life DT50= 94.1-135 days) than under aerobic (DT50= 42.4-91.3 days) incubation conditions for all management regimes. Leaching losses of bentazon were reduced from 78 and 74% in TS and TF to 61 and 62% in NTS7 and NTS respectively. The mid- and long-term implementation of sprinkler irrigation in combination with no-tillage could be considered a management system that is effective at reducing water contamination by bentazon in Mediterranean rice-growing agroecosystems. © 2017 Society of Chemical Industry.
Área de Edafología y Química Agrícola, Facultad de Ciencias - IACYS, Universidad de Extremadura, Badajoz, Spain.
Antonio
A
López-Piñeiro
Área de Edafología y Química Agrícola, Facultad de Ciencias - IACYS, Universidad de Extremadura, Badajoz, Spain.
David
D
Peña
Área de Producción Vegetal, Escuela de Ingenierías Agrarias - IACYS, Universidad de Extremadura, Badajoz, Spain.
Ángel
Á
Albarrán
Área de Edafología y Química Agrícola, Facultad de Ciencias - IACYS, Universidad de Extremadura, Badajoz, Spain.
Javier
J
Sánchez-Llerena
Escola Superior Agrária de Elvas, Elvas, Portugal.
José Manuel
JM
Rato-Nunes
Área de Producción Vegetal, Escuela de Ingenierías Agrarias - IACYS, Universidad de Extremadura, Badajoz, Spain.
María Ángeles
MÁ
Rozas
D057914:Agricultural Irrigation; D001581:Benzothiadiazines / Q000737:chemistry*; D000069599:Crop Production / Q000379:methods*; D006540:Herbicides / Q000737:chemistry*; D012275:Oryza; D014874:Water Pollutants, Chemical / Q000737:chemistry; D014876:Water Pollution / Q000517:prevention & control
D001581:Benzothiadiazines; D006540:Herbicides; D014874:Water Pollutants, Chemical; C002003:bentazone
aerobic and anaerobic rice; bentazon; leaching; persistence; sorption; tillage management