Procedures for Detection of Resistant Weeds Using 14C- Herbicide Absorption, Translocation, and Metabolism
By Kassio Ferreira Mendes, Ricardo Ferraz Silveira, Miriam Hiroko Inoue
and Valdemar Luiz Tornisielo
Herbicide resistance mechanisms involve altered absorption, translocation, and metabolism of herbicides (i.e., glyphosate), and this is an important component in the study of herbicide resistance mechanisms as well. 14C-herbicides are used in resistant weeds studies, since they provide some advantages in comparison with chemical measures, including greater sensitivity, stepwise description of a particular element in a metabolic system, herbicide position, detection through X-ray films and/or radio image, and liquid scintillation. However, an up-to-date, organized description and standardization of research procedures and methodology on the use of radioisotopes for detection of resistant weeds, through different mechanisms of absorption, translocation, and metabolism in comparison with susceptible weeds are lacking in the literature. Techniques that use 14C such as tracers are extremely useful to study the herbicides behavior in the resistant weed, since the radiometric techniques offer the possibility of accurately determining very small amounts in a relatively short time. However, mechanism of resistance to herbicides in this resistant weed population compared with the susceptible population cannot be due to differential absorption, translocation, or metabolism of herbicide in weed; so other studies are necessary to elucidate the mechanism of herbicide resistance on weed population.
Part of the book: Herbicide Resistance in Weeds and Crops
Effect of Biochar Amendments on the Sorption and Desorption Herbicides in Agricultural Soil
By Kassio Ferreira Mendes, Ananias Francisco Dias Júnior, Vanessa Takeshita,
Ana Paula Justiniano Régo and Valdemar Luiz Tornisielo
Improved understanding of herbicide destinations, effects, and environmental risks through worldwide studies is crucial to minimizing impacts to nontarget organisms, especially in tropical regions rich in biodiversity. In recent years, there has been widespread international concern about the toxic effects of herbicides on humans, faunas, and native floras. Therefore, the adoption of agricultural practices that minimize the environmental effects of herbicides has been frequently studied, for example, the addition of biochar in agricultural soils. Biochar can be defined as the by-product of a thermal process conducted under low oxygen or oxygen-free conditions (pyrolysis) to convert plant biomass to biofuels, where biochar is the solid product of pyrolysis. The addition of biochar to the soil can easily potentiate the herbicide retention process, which, in addition to contributing positively to the reduction of chemical contaminants in the environment, may exert negative effects on herbicide behavior and the efficacy of these products on weed control. Thus, this chapter will present the general characteristics of biochar, as well as the impact of this material on sorption-desorption of herbicides in the soil.
Part of the book: Advanced Sorption Process Applications
Water Resource Pollution by Herbicide Residues
By Kassio Ferreira Mendes, Ana Paula Justiniano Régo, Vanessa Takeshita and Valdemar Luiz Tornisielo
Herbicides are frequently used in the chemical control of weeds in various crops in Brazil and worldwide, so they are more frequently detected outside the application areas, contributing to the risk of environmental contamination. The importance of knowledge of the physicochemical properties of the environment and the pesticide used in the agricultural area is in order to understand its effects on terrestrial and aquatic ecosystems and the search for the prevention of future bioaccumulation potentials (bioconcentration and/or biomagnification) of molecules of pesticides in living nontarget organisms, minimizing their negative effects on the environment. The understanding of analytical techniques for measuring the quality of water resources as well as techniques for the remediation of contaminated water is essential to minimize the possible impacts caused by the application of pesticides to the environment.
Part of the book: Biochemical Toxicology
Current Approaches to Pesticide Use and Glyphosate-Resistant Weeds in Brazilian Agriculture
By Kassio Ferreira Mendes, Rodrigo Nogueira de Sousa and Ana Flávia Souza Laube
The aim of this chapter is to show a general vision about the pesticides use in Brazil. Pesticides are chemical products that contribute to agricultural production processes, mainly large scale, as agents of chemical, physical and biological processes. The glyphosate is the most widely used pesticide in Brazil to vast area cultivated with genetically modified glyphosate-resistant crops. Also, this herbicide is the most widely used in the world to control weeds in various crops, making chemical control cheap, easy and efficient. However, with the advance in the cultivation of glyphosate-resistant crops and the intensive use of this herbicide associated with the non-use of other herbicides, glyphosate-resistant weed biotypes are emerging very quickly. In this way, its use must be performed consciously in order not to occur significant increase in the amount of weeds resistant to this herbicide. Despite its great use in the country, it presents few records of resistant weeds when compared to other herbicide action mechanisms. Thus, good agricultural practices are indispensable and more innovations in technologies are necessary for the future. Therefore, adopting a long-term weed management perspective and integration systems for all agricultural practices is of paramount importance to farmers.
Part of the book: Multifunctionality and Impacts of Organic and Conventional Agriculture
Degradation Process of Herbicides in Biochar-Amended Soils: Impact on Persistence and Remediation
By Kamila Cabral Mielke, Kassio Ferreira Mendes, Rodrigo Nogueira de Sousa and Bruna Aparecida de Paula Medeiros
Biochar is a solid material derived from different feedstocks that is added to the soil for various agronomic and environmental purposes, such as nutrient sources and CO2 emission mitigators. In modern agriculture, the application of herbicides directly in the soil is common for pre-emergent weed control; however, biochars may interfere in the degradation processes of these agrochemicals, increasing or decreasing their persistence. Long persistence is desirable for some herbicides in determined cultivation systems, especially in monoculture, but persistence is undesirable in crop rotation and/or succession systems because the subsequent cropping can be sensitive to the herbicide, causing carryover problems. Therefore, knowing the interactions of biochar-herbicide is essential, since these interactions depend on feedstock, pyrolysis conditions (production temperature), application rate, biochar aging, among other factors; and the physical-chemical characteristics of the herbicide. This chapter shows that the addition of biochar in the soil interferes in the persistence or remediation processes of the herbicide, and taking advantage of the agricultural and environmental benefits of biochars without compromising weed control requires a broad knowledge of the characteristics of biochar, soil, and herbicide and their interactions.
Part of the book: Biodegradation Technology of Organic and Inorganic Pollutants
Integrated Weed Management in Coffee for Sustainable Agriculture – A Practical Brazilian Approach View all chapters
By Daniel Resende Fontes, Andrew de Paula Ribeiro, Marcelo Rodrigues dos Reis, Miriam Hiroko Inoue and Kassio Ferreira Mendes
Brazil is the largest coffee exporter in the world market and ranks second among coffee-consuming countries. The use of technology has been largely responsible for the great development of Brazilian agriculture in recent years. Then, the efficiency of integrated weed management has made the country more competitive in coffee farming. Therefore, integrated weed management (IWM) practices are the foundation for sustainable weed management in coffee fields. Weed competition cause losses in crop production. In weed control, besides chemical control, there are other methods that are efficient, economical, and beneficial to the coffee plant and to the environment that can be used on any property, such as preventive and cultural managements; and mechanical, biological, and physical controls. The combination of weed control methods has proven to be a sustainable practice in coffee production. In integrated management, the inherent advantages of each control method must be combined. Lastly, IWM provides an efficient control action with lower costs, better environmental conservation, and higher crop productivity. Thus, this chapter discusses the main practices of sustainable weed management in coffee, addressing issues such as competition, benefits, main weeds, and IWM systems.
Part of the book: New Insights in Herbicide Science