The role of conservation in United States' agricultural policy from the Dust Bowl to today: A critical assessment.

Historical evidence shows that environmental issues have been secondary to United States' agricultural policy since the first farm bill in 1933. The farm sector has undergone massive changes in technology and farming practices, but the environmental problems it causes have remained ancillary to productivist goals. Agri-environmental policy has continued to rely on subsidies and voluntary farmer participation, while combining environmental objectives with price and income support aims. The faith of agri-environmental programs is largely determined by what is desirable for safety net purposes, and in times of high crop and livestock prices and increased environmental pressures conservation is particularly underfunded. Additionally, monitoring and program assessment are poorly structured. This is particularly concerning today given the threats of climate change and agriculture's contribution to it. A major rethinking of these taxpayer-funded programs is necessary to improve their effectiveness. Programs should focus on environmental outcomes and monitoring and assessment should be strengthened.

The state of water quality strategies in the Mississippi River Basin: Is cooperative federalism working?

There is consensus that the Clean Water Act (CWA) has generally been effective in addressing point source pollution in the US. There is also consensus that non-point source (NPS) pollution, particularly from agriculture, remains a problem. The potential for the CWA framework to affect change is unclear, due to the limited power of the US federal government in addressing NPS, the contentiousness surrounding it, and the lack of funding to implement plans that have been developed. States are critical in improving water quality in the U.S. In the Mississippi River Basin, State-level Nutrient Reduction Strategies are the vehicle chosen by the Environmental Protection Agency to improve water quality. We develop an assessment of the twelve Mississippi River states' strategies. We consider three issues: whether there is science-based support for a choice, with a focus on NPS; if and how updates on progress are available; and whether there is alignment of funding and abatement priorities. We find that the use of best science is limited, the role of livestock in pollution and its abatement is ignored, and the development of Numeric Nutrient Criteria is stalled. Further, several states have not reported on their progress, and there has been little additional funding for pollution reduction. This analysis can inform broader discussions on decentralized approaches to address water quality.

Simulation of targeted pollutant-mitigation-strategies to reduce nitrate and sediment hotspots in agricultural watershed.

About 50% of U.S. water pollution problems are caused by non-point source (NPS) pollution, primarily sediment and nutrients from agricultural areas, despite the widespread implementation of agricultural Best Management Practices (BMPs). However, the effectiveness of implementation strategies and type of BMPs at watershed scale are still not well understood. In this study, the Soil and Water Assessment Tool (SWAT) ecohydrological model was used to assess the effectiveness of pollutant mitigation strategies in the Raccoon River watershed (RRW) in west-central Iowa, USA. We analyzed fourteen management scenarios based on systematic combinations of five strategies: fertilizer/manure management, changing row-crop land to perennial grass, vegetative filter strips, cover crops and shallower tile drainage systems, specifically aimed at reducing nitrate and total suspended sediment yields from hotspot areas in the RRW. Moreover, we assessed implications of climate change on management practices, and the impacts of management practices on water availability, row crop yield, and total agricultural production. Our results indicate that sufficient reduction of nitrate load may require either implementation of multiple management practices (38.5% with current setup) or conversion of extensive areas into perennial grass (up to 49.7%) to meet and maintain the drinking water standard. However, climate change may undermine the effectiveness of management practices, especially late in the 21st century, cutting the reduction by up to 65% for nitrate and more for sediment loads. Further, though our approach is targeted, it resulted in a slight decrease (~5%) in watershed average crop yield and hence an overall reduction in total crop production, mainly due to the conversion of row-crop lands to perennial grass. Such yield reductions could be quite spatially heterogeneously distributed (0 to 40%).

An Analysis of the Climate Change Mitigation Potential through Soil Organic Carbon Sequestration in a Corn Belt Watershed.

Land-based carbon sequestration constitutes a major low cost and immediately viable option in climate change mitigation. Using downscaled data from eight atmosphere-ocean general circulation models for a simulation period between 2015 and 2099, we examine the carbon sequestration potential of alternative agricultural land uses in an intensively farmed Corn Belt watershed and the impact of climate change on crop yields. Our results show that switching from conventional tillage continuous corn to no-till corn-soybean can sequester the equivalent of 192.1 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 2.26 MtCO2 eq ha-1 yr-1. Our results also indicate that switchgrass can sequester the equivalent of 310.7 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 3.65 MtCO2 eq ha-1 yr-1. Our findings suggest that, unlike for corn and soybean yields, climate change does not have a significant effect on switchgrass yields, possibly due to the carbon fertilization effect.

Tradeoffs of strategically reconnecting rivers to their floodplains: The case of the Lower Illinois River (USA).

During the latter half of the 19th Century and first half of the 20th Century, the Illinois River was heavily altered through leveeing off large portions of its floodplain, draining wetlands, and the construction of dams and river-training structures that facilitated navigation. As a result of these alterations, flood stages continue to rise, increasing flood risk and threatening to overtop levees along the La Grange Segment (LGS) of the Illinois River. Over the last two decades, more emphasis has been placed on reconnecting portions of floodplains to rivers in order to solve the long-term problem of rising flood heights attributed to continual heightening of levees to provide flood protection. Multiple studies have suggested that strategically reconnecting larger portions of the LGS could result in more sustainable floodplain management. However, the true costs and benefits of reconnecting the floodplain are not known. We use a novel hydrodynamic, geospatial, economic, and habitat suitability framework to assess the tradeoffs of strategically reconnecting the Illinois River to its floodplain in order to decrease flood risk, improve floodplain habitats, and limit the costs of reconnection. Costs include building-associated losses, lost agricultural profits, and levee removal and construction costs. Tested scenarios demonstrate that while flood heights and environmental benefits are maximized through the most aggressive levee setbacks and removals, these scenarios also have the highest costs. However, the tradeoff of implementing lower-cost scenarios is that there is less flood-height reduction and less floodplain habitat available. Several individual levee districts have high potential for reconnection based on limiting potential damages as well as providing floodplain habitat. To implement large-scale strategic floodplain reconnection, costs range from $1.2-$4.3 billion. As such, payments for ecosystem services will likely be necessary to compensate landowners for decreased long-term agricultural production and building losses that result in flood-reduction benefits and increased floodplain habitat.

Modeling Agricultural Watersheds with the Soil and Water Assessment Tool (SWAT): Calibration and Validation with a Novel Procedure for Spatially Explicit HRUs.

Applications of the Soil and Water Assessment Tool (SWAT) model typically involve delineation of a watershed into subwatersheds/subbasins that are then further subdivided into hydrologic response units (HRUs) which are homogeneous areas of aggregated soil, landuse, and slope and are the smallest modeling units used within the model. In a given standard SWAT application, multiple potential HRUs (farm fields) in a subbasin are usually aggregated into a single HRU feature. In other words, the standard version of the model combines multiple potential HRUs (farm fields) with the same landuse/landcover, soil, and slope, but located at different places of a subbasin (spatially non-unique), and considers them as one HRU. In this study, ArcGIS pre-processing procedures were developed to spatially define a one-to-one match between farm fields and HRUs (spatially unique HRUs) within a subbasin prior to SWAT simulations to facilitate input processing, input/output mapping, and further analysis at the individual farm field level. Model input data such as landuse/landcover (LULC), soil, crop rotation, and other management data were processed through these HRUs. The SWAT model was then calibrated/validated for Raccoon River watershed in Iowa for 2002-2010 and Big Creek River watershed in Illinois for 2000-2003. SWAT was able to replicate annual, monthly, and daily streamflow, as well as sediment, nitrate and mineral phosphorous within recommended accuracy in most cases. The one-to-one match between farm fields and HRUs created and used in this study is a first step in performing LULC change, climate change impact, and other analyses in a more spatially explicit manner.

An Examination of Growing Trends in Land Tenure and Conservation Practice Adoption: Results from a Farmer Survey in Iowa.

Tenants and part-owners are farming an increasing number of acres in the United States, while full-owners are farming fewer acres. This shift in ownership is a potential cause for concern because some previous research indicated that tenant and part-owner farmers were less likely to adopt conservation practices than farmers who owned the land they farmed. If that trend persists, ownership changes would signal a national drop in conservation adoption. Here we examine this issue using a survey of agricultural operators in the Clear Creek watershed in Iowa, a state with intensive agricultural production. We compare adoption of conservation practices, and preferences for conservation information sources and communication channels, between farmers who rent some portion of the land they farm (tenants and part-owners) and farmers who own all of the land they farm (full-owners). We find that renters are more likely to practice conservation tillage than full-owners, though they are less likely to rotate crops. In addition, renters report using federal government employees (specifically, Natural Resource Conservation Service and Farm Service Agency) as their primary sources of conservation information, while full-owners most frequently rely on neighbors, friends, and County Extension. These findings are significant for conservation policy because, unlike some past research, they indicate that renters are not resistant to all types of conservation practices, echoing recent studies finding an increase in conservation adoption among non-full-owners. Our results emphasize the importance of government conservation communication and can inform outreach efforts by helping tailor effective, targeted conservation strategies for owners and renters.

Human consumption as an invasive species management strategy. A preliminary assessment of the marketing potential of invasive Asian carp in the US.

Over the past 20 years, Asian carp have invaded rivers and lakes in the Midwest and southern United States, with large negative impacts, such as encroachment on the habitat of native fish and mass die-off. They also respond to boat motors by jumping out of the water, which can cause harm to boaters and fishermen. Policymakers in the Great Lakes region between the US and Canada are worried about possible expansion of the Asian carp to their region and its effects on their fishing industry. A potential solution to the problem is to harvest Asian carp for human consumption. This study analyzes the results of the first national survey on the attitudes of US fish consumers towards Asian carp. We find that this is a potentially promising strategy. Most respondents would be willing to try a free sample of Asian carp and would be willing to pay for it. Because of the negative connotation attached to carp in general, this figure is encouraging. Creating demand for Asian carp could be a market based, cost-effective solution for a problem (invasive species) that is typically dealt with through command and control policies, if it is coupled with appropriate policies and safeguards to ensure the fish is eventually eradicated and not cultivated for profit after removal from US rivers and lakes.

Potential water quality changes due to corn expansion in the Upper Mississippi River Basin.

While biofuels may yield renewable fuel benefits, there could be downsides in terms of water quality and other environmental stressors, particularly if corn is relied upon exclusively as the feedstock. The consequences of increased corn production will depend importantly on where (and how) the additional corn is grown, which, in turn, depends on the characteristics of land and its associated profitability. Previous work has relied on rules of thumb for allocating land to increased acreage based on historical land use or other heuristics. Here, we advance our understanding of these phenomena by describing a modeling system that links an economics-driven land use model with a watershed-based water quality model for the Upper Mississippi River Basin (UMRB). This modeling system is used to assess the water quality changes due to increased corn acreage, which is associated with higher relative corn prices. We focus on six scenarios based on six realistic pairs of corn and soybean prices which correspond to a scale of decreasing soybean to corn price ratio. These price-driven land use changes provide estimates of the water quality effects that current biofuel policies may have in the UMRB. Our analysis can help evaluate the costs and environmental consequences associated with implementation strategies for the biofuel mandates of the new energy bill. The amounts of total N and P delivered to the outlet of the UMRB (located at Grafton, Illinois, USA) rise as corn production becomes more intensive in the region. Our results indicate that a 14.4% in corn acreage in the watershed due to corn intensification in the most economically profitable locations would result in a 5.4% increase in total nitrogen loads and in a 4.1% increase in total phosphorus loads at Grafton. Our most aggressive scenario, driven by high but not out of reach crop prices, results in about a 57% increase in corn acreage with a corresponding 18.5% increase in N and 12% increase in P. These are somewhat conservative increases in nutrients, compared to those of previous studies, likely due to our focus on cultivated cropland which is already heavily fertilized.

Least-cost control of agricultural nutrient contributions to the Gulf of Mexico hypoxic zone.

In 2008, the hypoxic zone in the Gulf of Mexico, measuring 20 720 km2, was one of the two largest reported since measurement of the zone began in 1985. The extent of the hypoxic zone is related to nitrogen and phosphorous loadings originating on agricultural fields in the upper Midwest. This study combines the tools of evolutionary computation with a water quality model and cost data to develop a trade-off frontier for the Upper Mississippi River Basin specifying the least cost of achieving nutrient reductions and the location of the agricultural conservation practices needed. The frontier allows policymakers and stakeholders to explicitly see the trade-offs between cost and nutrient reductions. For example, the cost of reducing annual nitrate-N loadings by 30% is estimated to be US$1.4 billion/year, with a concomitant 36% reduction in P and the cost of reducing annual P loadings by 30% is estimated to be US$370 million/year, with a concomitant 9% reduction in nitrate-N.

Corn-based ethanol production and environmental quality: a case of Iowa and the conservation reserve program.

Growing demand for corn due to the expansion of ethanol has increased concerns that environmentally sensitive lands retired from agricultural production and enrolled into the Conservation Reserve Program (CRP) will be cropped again. Iowa produces more ethanol than any other state in the United States, and it also produces the most corn. Thus, an examination of the impacts of higher crop prices on CRP land in Iowa can give insight into what we might expect nationally in the years ahead if crop prices remain high. We construct CRP land supply curves for various corn prices and then estimate the environmental impacts of cropping CRP land through the Environmental Policy Integrated Climate (EPIC) model. EPIC provides edge-of-field estimates of soil erosion, nutrient loss, and carbon sequestration. We find that incremental impacts increase dramatically as higher corn prices bring into production more and more environmentally fragile land. Maintaining current levels of environmental quality will require substantially higher spending levels. Even allowing for the cost savings that would accrue as CRP land leaves the program, a change in targeting strategies will likely be required to ensure that the most sensitive land does not leave the program.