Abstract

CAPRILE, Ana Clara; SASAL, María Carolina; REPETTI, María Rosa  and  ANDRIULO, Adrián Enrique. Pesticides retained in soil and lost by runoff in two crop sequences under no tillage. Cienc. suelo [online]. 2019, vol.37, n.2, pp.338-354. ISSN 1850-2067.

Pesticides, after being applied, in addition to fulfilling their objective function, are distributed in the environment and they can be retained, degraded and/or transformed, or also transported from the application place. Crop sequence intensification degree can affect its fate in the environment. The objective of the work was to compare the presence of pesticides in the runoff water with simulated rain and in the soil profile up to one-meter depth, in two crop sequences under no tillage. The study is part of an essay comparison of long-term crop production systems implemented in the Pergamino pure series. Two treatments were used: corn-soybean-wheat/ soybean sequence (R) and soybean monoculture (S). In water and soil, the following compounds were determined: azoxystrobin, ciproconazol, carbendazim, cypermethrin, chlorpyrifos, 2,4-D, atrazine, glyphosate, aminomethylphosphonic acid (AMPA) and metsulfuron- methyl. The amounts lost by runoff were very small in relation to the amounts retained in the soil. R retained more pesticides in the soil profile (azoxystrobin, chlorpyrifos, 2,4-D, glyphosate) and it had lower detections in the runoff water (carbendazim, AMPA and metsulfuron-methyl) than S. When it was related the amount lost and retained with respect to the amount applied, accumulated after 9 years, again, in R, some pesticides were more retained (azoxystrobin, chlorpyrifos, 2,4-D) and others were lost less in the runoff (ciproconazole, atrazine) than in S. The maintenance of the soil quality through an important mulch on the surface and a relatively stable porous system accompanied by a reasonable reserve of organic carbon in the thickness 0-5 cm promotes biophysical degradation processes that reduce the exchange of pesticides between the agroecosystem and its environment.

Keywords : herbicides; insecticides; fungicides; simulated rain.