CHAPTER 1
1.0 INTRODUCTION
1.1 BACKGROUND OF STUDY
The production of food is basically through agricultural activities and by livestock. The amount of food produced is directly related with the relationship established between the species of interest for production and the other plant, animal, microbial and parasitic biological systems that compete for resources available in the environment (Ueta et al., 1997). Among the species that threaten the agricultural production there are the weeds that, when invade crops, can cause remarkable loss in the yield and quality of the harvest. Therefore, in order to improve the productivity and the quality of crops, the removal of weeds from agricultural farmlands becomes imperative.
The introduction of selective herbicides gave farmers a novel tool in the control of weeds (Kudsk and Streibig, 2003).
The use of these chemical agents resulted in the increase of productivity, but, on the other hand, brought unpleasant consequences, since …show more content…
An important chemical property of soil that can affect herbicide persistence is pH. Soil composition is a physical factor determined by the relative amounts of sand, silt, and clay in the soil (the soil texture), as well as by the organic-matter content. The types and abundance of soil microorganisms present in the soil make up the microbial aspects of the soil environment. Generally, soils high in clay, organic matter, or both have a greater potential for herbicide persistence because of increased binding of the herbicide to soil particles, with a corresponding decrease in leaching and loss through volatilization (William, 1998).
The climatic conditions involved in herbicide degradation are moisture, temperature, and sunlight. The rate of herbicide degradation generally increases as temperature and soil moisture increase, because both support microbial and chemical
1.0 INTRODUCTION
1.1 BACKGROUND OF STUDY
The production of food is basically through agricultural activities and by livestock. The amount of food produced is directly related with the relationship established between the species of interest for production and the other plant, animal, microbial and parasitic biological systems that compete for resources available in the environment (Ueta et al., 1997). Among the species that threaten the agricultural production there are the weeds that, when invade crops, can cause remarkable loss in the yield and quality of the harvest. Therefore, in order to improve the productivity and the quality of crops, the removal of weeds from agricultural farmlands becomes imperative.
The introduction of selective herbicides gave farmers a novel tool in the control of weeds (Kudsk and Streibig, 2003).
The use of these chemical agents resulted in the increase of productivity, but, on the other hand, brought unpleasant consequences, since …show more content…
An important chemical property of soil that can affect herbicide persistence is pH. Soil composition is a physical factor determined by the relative amounts of sand, silt, and clay in the soil (the soil texture), as well as by the organic-matter content. The types and abundance of soil microorganisms present in the soil make up the microbial aspects of the soil environment. Generally, soils high in clay, organic matter, or both have a greater potential for herbicide persistence because of increased binding of the herbicide to soil particles, with a corresponding decrease in leaching and loss through volatilization (William, 1998).
The climatic conditions involved in herbicide degradation are moisture, temperature, and sunlight. The rate of herbicide degradation generally increases as temperature and soil moisture increase, because both support microbial and chemical