Pesticide soil contamination interference in the diversity and abundance of soil communities and the soil carbon pools

• Grant number: 24/10455-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2024
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Fernando Luis Cônsoli
• Grantee: Ana Flávia Freitas Gomes
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 21/10573-4 - Center for Carbon Research in Tropical Agriculture (CCARBON), AP.CEPID

Abstract

Soil communities (arthropods, fungi, bacteria, and protists) play relevant roles in carbon processing, serving as key regulators of the soil carbon pool. But these organisms also suffer with the non-target effects of pesticide use. The correlation is easily seen with soil arthropods, as many pesticides that are broadly used carry conserved target-sites. And those particularly acting on the regulation of mechanisms of the nervous system (pyrethroids, carbamates, organophosphates) are highly toxic to several organisms, including mammals. Even the more selective pesticides (chitin synthesis inhibitors, juvenile hormone mimics) that have much lower non-target effects, including to insect pollinators, are risky to soil arthropods. The reduced risk to non-target organisms visiting plants treated with such pesticides occurs mainly due to their mode of action (ingestion instead of contact). However, contamination of the organic residues in soils will directly expose soil arthropods acting on the decomposition of the organic matter to these toxic molecules, which will suffer the effects of intoxification. But toxicity of pesticides to bacteria, fungi and protists is not uncommon, and pesticide can interfere directly and/or indirectly with the soil biota (Ferraro & Pimentel 2000, Arora & Sahni 2016, Fournier et al. 2020). The large spectrum of pests and the intensive agricultural practice in Brazil with crop rotation throughout the year keeps the soil invertebrates under constant exposure to pesticides even in areas with Bt technologies. Moreover, the rapid evolution of resistance to some of the Bt traits available (Farias et al. 2014, Omoto et al. 2016) and the recent description of cross-crop resistance due to the fact crops share Bt-traits and are cultivated in rotation (Yang et al. 2016, Machado et al. 2020), have unexpectedly prompt growers to increase pesticide applications in Bt areas.