Download or read book Pesticide Transport and Runoff Model for Agricultural Lands written by Norman H. Crawford and published by . This book was released on 1973 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pesticide transport and runoff model for agricultural lands written by Norman H. Crawford and published by . This book was released on 1973 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pesticide Transport and Runoff Model for Agricultural Lands written by U. S. Environmental Protection Agency and published by BiblioGov. This book was released on 2013-07 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.

Download or read book Modeling Pesticides and Nutrients on Agricultural Lands written by Anthony S. Donigian (Jr.) and published by . This book was released on 1976 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pesticides in the Soil Environment written by Hwei-Hsien Cheng and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pesticides in the soil environment - an overview. Pesticide sources to the soil and principles of spray physics. The retention processes: mechanisms. Sorption estimates for modeling. Abiotic transformations in water, sediments, and soil. Biological transformation processes of pesticides. Volatilization and vapor transport processes. Organic chemical transport to Groundwater. Movement of pesticides into surface waters. Modeling pesticide fate in soils. Efficacy of soil-applied pesticides. Impact of pesticides on the environment. Risk/benefit and regulations. Chemical index.

Download or read book Transport and Attenuation of Pesticides in Runoff from Agricultural Headwater Catchments written by Marie Lefrancq and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding pesticide transport is crucial to evaluate their ecological impact on ecosystems. Current knowledge on the spatial variability of pesticide deposition, the impact of erosion on pesticides export and the in situ pesticide degradation is very limited at the catchment scale. In this thesis, characterisation and modeling at two scales, the plot and catchment, were combined in two agricultural contexts. A formalism was developed to predict pesticide transport in runoff and was integrated in LISEM (LImbourg Soil Erosion Model). The results show that impermeable roads contributed to more than 40% to the overall load of fungicides exported via runoff from the vineyard. Pesticide partitioning between suspended solids and runoff water differed largely according to the molecules and the hydrological dynamics. The occurrence of degradation products and the enrichment of one enantiomer were observed suggesting the potential of chiral analyses for assessing biodegradation of chiral pesticides at such scale. Overall, the investigation demonstrated that combining different approaches enable a better understanding of pesticide transport.

Download or read book Field Agricultural Runoff Monitoring FARM Manual written by and published by . This book was released on 1985 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transport of Agricultural Chemicals from Small Upland Piedmont Watersheds written by and published by . This book was released on 1978 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil and Water Quality written by National Research Council and published by National Academies Press. This book was released on 1993-02-01 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: How can the United States meet demands for agricultural production while solving the broader range of environmental problems attributed to farming practices? National policymakers who try to answer this question confront difficult trade-offs. This book offers four specific strategies that can serve as the basis for a national policy to protect soil and water quality while maintaining U.S. agricultural productivity and competitiveness. Timely and comprehensive, the volume has important implications for the Clean Air Act and the 1995 farm bill. Advocating a systems approach, the committee recommends specific farm practices and new approaches to prevention of soil degradation and water pollution for environmental agencies. The volume details methods of evaluating soil management systems and offers a wealth of information on improved management of nitrogen, phosphorus, manure, pesticides, sediments, salt, and trace elements. Landscape analysis of nonpoint source pollution is also detailed. Drawing together research findings, survey results, and case examples, the volume will be of interest to federal, state, and local policymakers; state and local environmental and agricultural officials and other environmental and agricultural specialists; scientists involved in soil and water issues; researchers; and agricultural producers.

Download or read book Modeling of Agrochemical Transport in California s Surface Water and Retention by Vegetated Filter Strips written by Huajin Chen and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last century, use of pesticides and fertilizers has enabled a tremendous increase in agriculture productivity worldwide. At the same time, documentation of contamination and adverse effects of agrochemical residues in the environment and aquatic ecosystem grows. A mechanistic and quantitative understanding of pesticide fate and transport in agricultural fields and watersheds is essential for informed decisions on regional water quality management. This study focuses on modeling agrochemical transport in California’s surface water and the pesticide removal efficacy of Vegetated Filter Strips (VFS’s). First, two newly-released, widely-used, field-scale numerical models, the Root Zone Water Quality Model (RZWQM) and the Pesticide Root Zone Model (PRZM), were compared and evaluated in terms of their abilities to predict sediment and pesticide runoff from two alfalfa fields in Davis, California. A composite metric (based on R2, NSE, d, and PBIAS) was developed and employed to ensure robust, comprehensive assessment of model performance. The RZWQM and PRZM models predicted surface water runoff reasonably well (absolute percent bias 31%) after adjusting important hydrologic parameters but with a consistent underestimation bias (-89% ≤ percent bias ≤ -36%) for sediment yield. Chlorpyrifos losses were simulated with reasonable accuracy especially for field A (absolute percent bias ≤ 22%), whereas diuron losses were underestimated to a great extent (-98% ≤ percent bias ≤ -65%) by both models. Based on this study, both RZWQM and PRZM performed well in predicting runoff that carried moderately adsorbed pesticides on an event basis, although the more physically based RZWQM is recommended when field-measured soil hydraulic properties are available. Next, to quantify VFS efficacy in reducing pesticide runoff, a meta-regression model was developed based on hydrologic responses of VFS’s, incoming pollutant characteristics, and interactions within and between these two factor groups (Q2 = 0.83). In cross-validation analysis, the developed model (Q2 = 0.81) outperformed the existing pesticide retention module of VFSMOD (Q2 = 0.72) by explicitly accounting for interaction effects and the categorical effect of pesticide adsorption properties. Based on the 181 data points studied, infiltration had a leading and positive influence on pesticide retention, followed by sedimentation and interactions between the two. Interactions between infiltration and pesticide adsorption properties were prominent, and the clay content of incoming sediment was negatively associated with pesticide retention. Next, we applied the Soil and Water Assessment Tool (SWAT) to watershed-scale simulation of pesticide fate and transport in the agriculturally intensive San Joaquin River watershed. This watershed is a major contributor to elevated pesticide levels in the downstream Sacramento-San Joaquin Delta where a biological weed control plan is under development. The Sequential Uncertainty Fitting version 2 algorithm was employed to perform calibration and uncertainty analyses. A combination of performance measures and standardized performance evaluation criteria was applied to evaluate model performance, and prediction uncertainty was quantified using the 95% Prediction Uncertainty band (95PPU). Results showed that streamflow simulation was at least “satisfactory” at most stations, with more than 50% of the observed data bracketed by the 95PPU. Sediment simulation was rated as at least “satisfactory” based on two performance measures, and diuron simulation was judged as “good” by all performance measures. The 95PPU of sediment and diuron bracketed about 40% and 30% of the observed data, respectively. Results also showed that the majority ( 70%) of agricultural diuron was transported during winter months, when direct exposure of biocontrol agents to diuron runoff is limited. Finally, the SWAT model together with the Sequential Uncertainty Fitting version 2 algorithm were applied to model riverine nitrate-nitrogen loads in the San Joaquin River watershed, where part of the area is poorly drained. We found that the new tile drainage routine in SWAT significantly improved nitrate load simulations. Nitrate simulations were rated as at least “satisfactory” for all the monitoring stations based on R2 and PBIAS. The P-factor was more than 0.5 and the average R-factor was about 1.2, indicating that a balance was reached between uncertainty measures and the strength of calibration. The major sources of uncertainty include the lack of information regarding the timing and magnitude of fertilizer and manure applications. The SWAT simulation indicated that 40% of riverine nitrate loads in the San Joaquin River watershed came from tile drainage nitrate. The San Joaquin River plays an important role in supplying nitrogen to the Delta by exporting 3,150 tons of nitrate-nitrogen annually. In summary, results from this dissertation indicate that: (1) preferential flow through macropore is an important transport pathway in undisturbed soil and mechanistic hydrologic models should be used to account for such field conditions; (2) interactions among hydrological and pesticide adsorption processes have significant effects on VFS pesticide retention; and (3) dominant hydrologic processes and associated parameter sensitivity vary spatially, and therefore it is important to perform rigorous multi-site calibration when simulating pollutant transport across large watersheds. The study not only facilitates a deeper understanding of hydrologic processes occurring in croplands, VFS’s, and agricultural watersheds, but also serves as a foundation for the continued research on calibration, evaluation, and uncertainty analysis of spatially distributed, physically based hydrologic models.

Download or read book EPA 600 2 written by and published by . This book was released on 1979 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on with total page 1386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiresource Management of Southwestern Ponderosa Pine Forests written by and published by . This book was released on 1991 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lower Bayou Teche Watershed written by and published by . This book was released on 1979 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effectiveness of Soil and Water Conservation Practices for Pollution Control written by Douglas A. Haith and published by . This book was released on 1979 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings Workshop on Agricultural Non point Source Water Pollution Control September 16 and 17 1974 Washington D C written by and published by . This book was released on 1974 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impact of abandoned wells on ground water written by Tyler E. Gass and published by . This book was released on 1977 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: