Effect of cropping cycles and repeated herbicide applications on the degradation of diclofop-methyl, bentazone, diuron, isoproturon and pendimethalin in soil

• Published in: Pest management science 2002-03, Vol.58 (3), p.303-312
• Main Authors: Piutti, Severine, Marchand, Anne-Laure, Lagacherie, Bernard, Martin-Laurent, Fabrice, Soulas, Guy
• Format: Article
• Language: English
• Subjects: Agriculture - methods; Agronomy. Soil science and plant productions; Aniline Compounds - chemistry; Aniline Compounds - metabolism; Bacteria - drug effects; bentazon; Benzothiadiazines - chemistry; Benzothiadiazines - metabolism; biodegradation; Biological and medical sciences; Biomass; Brassica napus; Carbon Dioxide - metabolism; Carbon Radioisotopes; corn; crops; Crops, Agricultural - microbiology; degradation; diclofop-methyl; diuron; Diuron - chemistry; Diuron - metabolism; Environment, Controlled; environmental fate; Environmental Sciences; Fundamental and applied biological sciences. Psychology; Glycine max; greenhouses; Halogenated Diphenyl Ethers; herbicide; Herbicides - chemistry; Herbicides - metabolism; Herbicides - pharmacology; isoproturon; Kinetics; Life Sciences; Methylurea Compounds - chemistry; Methylurea Compounds - metabolism; microbial biomass; mineralization; Minerals - chemistry; Minerals - metabolism; pendimethalin; pesticide application; Phenyl Ethers - chemistry; Phenyl Ethers - metabolism; Phenylurea Compounds; phytostimulation; planting; rhizosphere; soil; Soil - analysis; Soil and water pollution; Soil Microbiology; Soil science; soybeans; Triticum; wheat
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.459

A greenhouse study was conducted to investigate the ability of four crops (wheat, corn, oilseed rape and soybean) to influence the degradation of bentazone, diclofop-methyl, diuron, isoproturon and pendimethalin in soil. The present study showed that microbial biomass-carbon was significantly higher in planted soils than in bulk soil, especially with wheat and corn, after several cropping cycles. The biomass in corn and soybean planted soils was adversely affected by bentazone but recovered after three cropping cycles. In wheat-planted soils, diclofop-methyl application resulted in persistent increase of the amount of microbial biomass. Bentazone did not show accelerated degradation even after five successive treatments, differing from diclofop-methyl, for which two applications were sufficient to enhance significantly its rate of degradation. Enhanced degradation of diclofop-methyl was even more pronounced in wheat-planted soil. The rates of mineralisation of diuron, isoproturon and pendimethalin were not affected after the first cropping cycle, but were significantly increased in planted soils after five cropping cycles. The results confirm that plants may promote pesticide degradation in soil by stimulating biodegradation processes. In the case of diclofop-methyl, stimulation of accelerated degradation was observed.