Joseph Gillet

Effects of fertilizer on insecticides adsorption and biodegradation in crop soils.

Recent organic fertilizer treatments (cow manure, pig slurry, composts, or green manure) simultaneously increase insecticide adsorption onto soil and the insecticide soil persistence, indicating a mechanism of slow release of insecticide into soil by the organic matter. This occurred in sugar beet crops with aldicarb, thiofanox and imidacloprid; also, in leek, cauliflower and brussels sprouts crops with chlorpyrifos and chlorfenvinphos. In contrast, organic fertilizer treatments applied once or repeatedly in the past, have no significant influence on adsorption or persistence of insecticides; the same is observed for the old soil organic matter, when its soil concentrations change in limited ranges.

Soil and Plant Biodegradation of Chlorpyrifos in Fields of Cauliflower and Brussels-sprouts Crops

For the protection of early and summer cauliflower and brussels sprouts crops against root fly, the insecticide chlorpyrifos was applied at planting onto soil around the stem of the plant, or in the planting line. In the soil, chlorpyrifos (1) was transformed into the insecticide metabolites oxon, 0,0‐diethyl‐0‐(3,5,6‐tri‐chloro‐2‐pyridinyl) phosphate (2), and 3,5,6‐trichloro‐2‐pyridinol (3). The soil half life time of chlorpyrifos could be 2.8 times greater (42 days relative to 15 days) when the field history as to cauliflower monoculture and insecticide treatments was short (1 year), than when it was long (8 years). Rains and season also had cumulative effects on the chlorpyrifos soil half life times. In the leaves of cabbage, chlorpyrifos and compound 3 were observed at concentrations which were higher, especially when their soil concentrations were high. Chlorpyrifos and compounds 2 and 3 however were not detected in the “flower” of cauliflower, nor in the brussels sprouts itself, the limit of sensiti...

Influence of cow manure and composts on the effects of chlorfenvinphos on field crops.

Cauliflower crops were grown in several regions and seasons (spring and summer). Five days after planting, the plants were treated against the root fly by pouring onto soil around the plant stem an emulsion of chlorfenvinphos [2-chloro-1-(2,4-dichlorophenyl) ethenyl diethyl phosphate] in water. The fields were divided into plots. Onto each plot, one of the organic fertilizers, city refuse compost, mushroom cultivation compost, or cow manure was applied at the rate of 100 tons/ha, 1 or 3.5 months before the insecticide treatment. There were also control plots which were not treated with any of the organic fertilizers. During the first 50 days crop period which followed the insecticide treatment, the chlorfenvinphos soil concentrations were always greater in the organic fertilizer-treated plots, than in the untreated ones (controls). The intensity of the organic fertilizers effect as to the increase of chlorfenvinphos soil persistence was in the following increasing order: city refuse compost < cow manure < mushroom cultivation compost. The organic fertilizer effects were greater when they had been soil-incorporated 3.5 months—instead of 1 month—before the chlorfenvinphos soil treatment. The increase of the insecticide soil concentrations—due to the organic fertilizers treatments—should increase the plant protection efficiency during the period of the first 50 days, during which time the young plants are the most sensitive to insects. During the following period of the 2 or 3 last crop weeks, the effects of the organic fertilizers onto the rate of chlorfenvinphos soil metabolism were levelled off; at harvest, the very low soil-resting residues were similar in the organic fertilizers treated and untreated plots. At harvest, no chlorfenvinphos nor its metabolites were detected in the ‘flower’ of cauliflower of all the plots, the analytical limit of sensitivity being 0.02 mg kg−1 fresh weight for all of these compounds.

Chlorpyrifos Soil and Plant Metabolisms in Cauliflower Crops Grown On Cow Manure and Composts Soil Fertilized Fields

Several cauliflower crops were grown on fields located in different regions. Cauliflower plants were treated against the root fly by applying, some days after planting, chlorpyrifos onto the soil around the stem of the plant. Fields were divided into plots. Either one or 3.5 months before planting, one of the organic fertilizers city refuse compost, or mushroom cultivation compost, or cow manure was incorporated into the soil of each plot; there were also soil unamended control plots. The rates of chlorpyrifos soil metabolism were smaller in the organic fertilizers amended plots, than what they were in the unamended plots. In the summer cauliflower crop made on loamy sand soil, the chlorpyrifos soil half‐lives were 41, 44, 53 and 25 days, respectively in the plots amended either with the city refuse compost, or cow manure, or the mushroom cultivation compost, and in the unamended plots. The organic fertilizers effects were slightly greater when the amendments had been soil incorporated 3.5 months before p...

Comparative soil and plant metabolism of carbosulfan, furathiocarb and carbofuran in Brussels sprouts, cauliflower and sugar beet crops

Brussels sprouts and cauliflower crops were soil treated at planting by one of the insecticides carbosulfan, furathiocarb, or carbofuran; moreover, a sugar beet crop was soil treated by carbofuran applied in the sowing furrow. In the soil, carbosulfan and furathiocarb were transformed into carbofuran, which then was transformed mainly into 3‐ketocarbofuran, carbofuran phenol, and 3‐ketocarbofuran phenol. In the soil of the carbosulfan treated crop, the carbosulfan and carbofuran concentrations were similar. In the carbosulfan treated soil, the concentrations of the sum carbosulfan‐+ carbofuran were higher than the carbofuran concentrations in the carbofuran treated soil. The chemical derivatization of the carbamate function which occurs in carbosulfan thus slowed down its soil biodegradation relative to the non derivatized carbamate function in carbofuran. The same occurred with furathiocarb, but with a lower intensity. When the soil microbial activity was exceptionally enhanced (by the climate and by a l...

Soil metabolism of the herbicide chlorbromuron in rape celery crops

Abstract In a 2-year study, the herbicide chlorbromuron was applied to the soil of rape celery crops grown in greenhouses (glass, polyethylene or polycarbonate) or in the field (with or without plastic sheet) in two regions with different soil types. Chlorbromuron and 4-bromo-3-chloraniline were measured in the soils. The half-life of chlorbromuron in soil was 55–66 days in the greenhouses, and 30–43 days in the field. 4-Bromo-3-chloraniline was generated by microbial and enzymatic processes; its concentration at harvest in soil was 500 ng g −1 dry soil. At harvest, in the bulb of the rape celery, the concentrations of chlorbromuron and of 4-bromo-3-chloraniline were equal or lower than 20 ng g −1 weight. The herbicide efficience is discussed in relationship to chlorbromuron soil concentrations.

Herbicides interactions with cow manure and field soil organic matter

Abstract The direct interaction of the herbicide metazachlor ‐chosen as an example‐ with the soil organic matter has been studied by laboratory incubation of old and young cow manures containing metazachlor. The extraction efficiencies of solvents of increasing polarities indicated the formation of association compounds by bonds weaker than covalent between metazachlor and the organic matter: electron donor‐acceptor complexes, hydrogen bonding complexes, and complexes by both bonding types. Laboratory incubation of metazachlor in soil of low organic matter content indicated that the soil mineral part only had a diluting effect on the soil organic matter capacity to adsorb metazachlor. Similar association compounds were observed in the soil of a cauliflower field crop. Their concentrations were greater in the plots treated with organic fertilizers than in the organic fertilizers untreated plots. The free‐ unbound metazachlor was faster metabolized than the one bound to the soil organic matter, explaining w...

Transport of the insecticides chlorpyrifos, chlorfenvinphos, carbofuran, carbosulfan, and furathiocarb from soil into the foliage of cauliflower and brussels sprouts plants grown in the field

In several field assays made in different locations in 1988 and 1989, cauliflower and Brussels sprouts plants were treated some days after plantation by pouring onto soil around the stem of the plant one of the insecticides chlorpyrifos, chlorfenvinphos, carbofuran, carbosulfan, or furathiocarb, for protection against the root fly. During plant growth, each of the insecticides (and their soil metabolites) was transported from soil into the plant foliage, where it could give—during a certain period of time—a secondary plant protection against the foliage insects. The foliage concentrations of the non systemic chlorpyrifos and chlorfenvinphos were equal or greater than 1 mg/kg fresh weight during a period of about 44 days after soil treatment in Brussels sprouts crops, and 35 days in cauliflower crops. Comparison of 1988 and 1989 however showed that these periods of time changed according to the weather conditions, especially rainfall. These periods of time were greater when the insecticide soil concentrati...

Effects of the soil organic fertilizers onto the carbofuran soil and plant metabolisms in field cauliflower crops

A spring cauliflower crop was made on the loamy sand soil of a field whose plots had been amended, one month before planting, with one of the organic fertilizers: city refuse compost, or mushroom cultivation compost, or cow manure; there were also unamended control plots. Some days after planting, an emulsion of carbofuran in water was applied onto soil, around the stem of the plant, for protection against the root fly. During growth of the crop, the rates of carbofuran soil biodegradation were smaller in the organic fertilizers amended plots, than in the unamended controls; the intensity of the effect was in the increasing order: city refuse compost < cow manure < mushroom cultivation compost. The organic fertilizers thus increased the insecticide soil concentrations; they thus should increase the insecticide protection efficiency against soil insects. During the final period of the crop, the rates of carbofuran soil biodegradation increased, and the organic fertilizers effects were levelled off; at harv...