Pesticide Fate Research Trends within a Strict Regulatory Environment: The Case of Germany

Germany has adopted tough regulations to prevent environmental contamination from agricultural chemicals. This is exemplified by strict standards for drinking water that limit chemical concentrations to 0.1 part-per-billion (ppb), regardless of toxicity. Current German regulatory and research trends are described, with an emphasis on basic pesticide fate research. Several key trends are identified: (1) protection of ground water, surface water, and the atmosphere are all important regulatory priorities, (2) computer models, soil lysimeters, and monitoring play critical roles in regulation and research, (3) increased emphasis is being placed upon multidisciplinary studies to address complex research problems, and (4) solutions are being sought to meet the regulatory goal of absolute protection of drinking water, especially ground water

Allocating Nutrient Load Reduction across a Watershed: Implications of Different Principles

A watershed based model, the Soil and Water Assessment Tool (SWAT), along with transfer coefficients is used to assess alternative principles of allocating nutrient load reduction in the Raccoon River watershed in central Iowa. Four principles are examined for their cost-effectiveness and impacts on water quality: absolute equity, equity based on ability, critical area targeting, and geographic proximity. Based on SWAT simulation results, transfer coefficients are calculated for the effects of nitrogen application reduction. We find both critical area targeting and downstream focus (an example of geographic proximity) can be more expensive than equal allocation, a manifestation of absolute equity. Unless abatement costs are quite heterogeneous across the subwatersheds, the least-cost allocation (an application of the principle of equity based on ability) have a potential of cost savings of about 10% compared to equal allocation. We also find that the gap between nitrogen loading estimated from transfer coefficients and nitrogen loading predicted by SWAT simulation is small (in general less than 5%). This suggests that transfer coefficients can be a useful tool for watershed nutrient planning. Sensitivity analyses suggest that these results are robust with respect to different degrees of nitrogen reduction and how much other conservation practices are used.Environmental Economics and Policy,

Carbon Sequestration, Co-Benefits, and Conservation Programs

Land use changes to sequester carbon also provide ﾓco-benefits,ﾔ some of which (for example, water quality) have attracted at least as much attention as carbon storage. The non-separability of these co-benefits presents a challenge for policy design. If carbon markets are employed, then social efficiency will depend on how we take into account co-benefits, that is, externalities, in such markets. If carbon sequestration is incorporated into conservation programs, then the weight given to carbon sequestration relative to its co-benefits will partly shape these programs. Using the Conservation Reserve Program (CRP) as an example, we show that CRP has been sequestering carbon, which was not an intended objective of the program. We also demonstrate that more carbon would have been sequestered had CRP targeted this objective, although the ﾓco-benefitsﾔ would have increased or decreased.

Potential Adoption of Managed Aquifer Recharge Systems in the Corn Belt Region

Managed aquifer recharge (MAR) is a technique for improving groundwater recharge and maintaining aquifer levels to support water storage for water treatment systems and irrigation for agricultural production or other water needs. MAR is an effective buffer against future fluctuations in water demand, drought, and climate change. MAR systems include bank filtration, infiltration ponds/galleries, percolation tanks, and aquifer storage and recovery (ASR) wells (Page et al. 2018; Dillon et al. 2019; Alam et al. 2021). In the United States, MAR system use has increased for several reasons including water shortages, greater need for reliable seasonal water sources, and favorable costs (Bray 2020; Page et al. 2018; Pyne 2005). Dillon et al. (2019) report that average annual total MAR volume in the United States was 2,569 million cubic meters (MCM)/year in 2015. However, wider adoption of MAR systems has been hindered by uncertainty in determining appropriate site conditions and MAR method (Alam et al. 2021), lack of economic data (Maliva 2014), and legal, policy, and/or environmental issues (Bray 2020)

The Environmental Component of the National Pilot Project Integrated Modeling System

An integrated modeling system has been constructed for the Upper North Bosque River Watershed (UNBRW) in Erath and Hamilton Counties, Texas, to simulate the movement of nutrients from dairy waste disposal fields. The authors describe the environmental component of that modeling system, focusing on the assumptions used in configuring the models for the UNBRW and the linkages between them

Environmental Conservation in Agriculture: Land Retirement Versus Changing Practices on Working Land

The study develops a conceptual framework for analyzing the allocation of conservation funds via selectively offering incentive payments to farmers for enrolling in one of two mutually exclusive agricultural conservation programs: retiring land from production or changing farming practices on land that remains in production. We investigate how the existence of a pre-fixed budget allocation between the programs affects the amounts of environmental benefits obtainable under alternative policy implementation schemes. The framework is applied to a major agricultural production region using field-scale data in conjunction with empirical models of land retirement and conservation tillage adoption, and a biophysical process simulation model for the environmental benefits of carbon sequestration and reduction in soil erosion.

Interactive APEX (i_APEX) USER’S GUIDE USING APEX2110 and APEX0806

A tool for managing large numbers of APEX runs, handling data input and output. Program Components: ACCESS Database: Contains input tables used by i_APEX to construct APEX runs and output tables to organize APEX output. Graphical User Interface: Allows for single runs and ranges of runs and permits editing of input data as well as selection of output variables and output files

Comparison of Land Use Area Estimates from Three Different Data Sources for the Upper Mississippi River Basin

This study presents the results of comparing land use estimates between three different data sets for the Upper Mississippi River Basin (UMRB). The comparisons were performed between the U.S. Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) National Resource Inventory (NRI), the U.S. Geological Survey (USGS) National Land Cover Data (NLCD) database, and a combined USDA National Agricultural Statistics Service (NASS) Agricultural Census – NLCD dataset created to support applications of the Hydrologic Unit Model for the U.S. (HUMUS). The comparison was performed for 1992 versions of the datasets because that was the only consistent year available among all three data sources. The results show that differences in land use area estimates increased as comparisons shifted from the entire UMRB to smaller 4- and 8-digit watershed regions (as expected). However, the area estimates for the major land use categories remained generally consistent among all three data sets across each level of spatial comparison. Differences in specific crop and grass/forage land use categories were magnified with increasing refinement of the spatial unit of comparison, especially for close-grown crops, pasture, and alfalfa/hayland. The NLCD close-grown crop area estimates appear very weak relative to the NRI and HUMUS, and the lack of specific crop land use estimates limits its viability for UMRB agricultural-based modeling scenarios. However, the NLCD is a key source of non-agricultural land use data for HUMUS and supplemental wetland land use area estimates for the NRI. We conclude that comparisons between more recent versions of the data sets (i.e., 1997 NRI, 1997 or 2002 Agricultural Census, and 2001 NLCD) would not result in significant additional insights and that the 1997 NRI is a viable land use data source for current CARD UMRB water quality modeling studies. However, adoption of other land use data such as USDA-NASS remote sensing data should be investigated

Optimal Placement of Conservation Practices Using Genetic Algorithm with SWAT

The effectiveness of conservation practices depends on their placement on the fields within the watershed. Cost-effective placement of these practices for maximum water quality benefits on each field requires comparing a very large number of possible land-use scenarios. To address this problem, we combine the tools of evolutionary algorithm with the Soil and Water Assessment Tool (SWAT) model and cost data to develop a trade-off frontier of least cost of achieving nutrient reductions and the corresponding locations of conservation practices. This approach was applied to the Raccoon River Watershed, which drains about 9,400 km2 of an intensive agriculture region in west-central Iowa. Applying genetic algorithm to the calibrated SWAT modeling setup produced multitudes of optimal solutions of achieving nutrient reductions in relation to the total cost of placing these practices. For example, a 30% reduction in nitrate (and a corresponding 53% reduction in phosphorus) at the watershed outlet can be achieved with a cost of $80 million per year. This solution frontier allows policymakers and stakeholders to explicitly see the trade-offs between cost and nutrient reductions