tailieunhanh - ORGANIC SOILS and PEAT MATERIALS for SUSTAINABLE AGRICULTURE - CHAPTER 8

Số phận của thuốc trừ sâu trong đất hữu cơ Chương này đánh giá các kiến thức hiện hành về số phận của thuốc trừ sâu khi áp dụng cho đất hữu cơ. Thuốc trừ sâu duy trì, quá trình kiểm soát số phận và kiên trì của thuốc bảo vệ thực vật trong đất, phụ thuộc vào thuốc trừ sâu chính tài sản đó như phân cực và sợ nước, và trên đất số lượng chất hữu cơ và chất lượng. | CHAPTER 8 Fate of Pesticides in Organic Soils Josée Fortin CONTENTS Abstract I. Introduction II. Pesticides Retention by Soil Organic Matter A. Pesticide Properties Affecting Their Retention by Soils B. Soil Organic Matter Composition C. Mechanisms of Pesticide Retention by SOM D. Quantitative Description of Pesticide Retention by SOM E. Pesticide-Bound Residues III. Pesticide Fate in Organic Soils A. Crop Uptake B. Pesticide Degradation C. Wind and Water Erosion D. Leaching and Colloid Facilitated Transport IV. Field Persistence of Selected Pesticides V. Effects of Pesticides on Microflora and Biochemical Processes VI. Concluding Remarks References ABSTRACT This chapter reviews the current knowledge on pesticides fate when applied to organic soils. Pesticide retention the process controlling the fate and persistence of pesticides in soils depends on key pesticides properties such as polarity and hydrophobicity and on soil organic matter quantity and quality. Generally pesticide 2003 by CRC Press LLC retention is higher in soils where the organic matter is in a more decomposed stage although contradictory results are reported. Pesticide retention by organic soils can be irreversible and produce bound residues. The long-term fate and environmental importance of bound residues in organic soils is unknown. Some processes that decrease pesticide concentration in organic soils such as plant uptake degradation erosion and leaching are discussed. The overall persistence of pesticides in surface horizons is higher in organic than in mineral soils. This persistence is usually related to pesticide retention by soil components and can result in soil accumulation of some pesticides with time. The pesticides applied to organic soils can affect biochemical processes and microbial activities. Generally the results reported show that the effects do not persist for a long period of time. I. INTRODUCTION Most pesticides interact with soil organic matter Turco and Kladivko 1994 .