Impact of biofumigation with solarization on degradation of pesticides and heavy metal accumulation

Abstract

A greenhouse study was conducted to evaluate the effect of biofumigation (with sheep and chicken manure) combined with solarization on the dissipation of pesticides (pyrifenox, DDT and dieldrin), and on soil metals accumulation. The treatments consisted of a control, and soil disinfestations by biofumigation combined with solarization (B+S) for two, four, five, six consecutive years. B+S enhanced the dissipation of pyrifenox with regard to control treatment. Significant differences were not detected among plots disinfected with B+S for consecutive years. On the other hand, B+S had no effect on the dissipation of DDT and dieldrin, probably due to the resistance of these pesticides to microbial degradation and/or high temperatures. Biofumigation is considered to be an environmentally safe practice, since no accumulation of heavy metals such as Cd, Co, Cu, Cr, Pb, Ni, or Zn was observed after the subsequent application of organic matter through the treatments.

Keywords:

• Organic amendment
• methyl bromide
• pesticides
• pyrifenox
• DDT
• dieldrin

Acknowledgment

The authors acknowledge financial support from Instituto Nacional de Investigación y Tecnología Agraria y alimentaria (INIA), Ministerio de Educación y Ciencia, research project number RTA2005-00127-00-00 and from Secretaría General para la Prevención de la Contaminación y el Cambio Climático del Ministerio de Medio Ambiente, research Project number 1.2-006/2005/3-B.

Notes

* Q/T (%) ratios are the results of abundance values of the qualifier ion (Q₁, Q₂) divided by the abundance of the target ion (T) x100.

*Significant differences (p < 0.01) between dissipation percentage means, according to ANOVA test, at a confidence level of 95%.