RESUMO
Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland. In a catchment-scale experiment, we quantified the multiple effects of integrating strips of native prairie species amid corn and soybean crops, with prairie strips arranged to arrest run-off on slopes. Replacing 10% of cropland with prairie strips increased biodiversity and ecosystem services with minimal impacts on crop production. Compared with catchments containing only crops, integrating prairie strips into cropland led to greater catchment-level insect taxa richness (2.6-fold), pollinator abundance (3.5-fold), native bird species richness (2.1-fold), and abundance of bird species of greatest conservation need (2.1-fold). Use of prairie strips also reduced total water runoff from catchments by 37%, resulting in retention of 20 times more soil and 4.3 times more phosphorus. Corn and soybean yields for catchments with prairie strips decreased only by the amount of the area taken out of crop production. Social survey results indicated demand among both farming and nonfarming populations for the environmental outcomes produced by prairie strips. If federal and state policies were aligned to promote prairie strips, the practice would be applicable to 3.9 million ha of cropland in Iowa alone.
Assuntos
Agricultura/métodos , Biodiversidade , Valores Sociais , Animais , Aves , Humanos , Insetos , Iowa , Solo , Glycine max , Zea maysRESUMO
The US Cornbelt leads North American production of intensively managed, row-crop corn and soybeans. While highly productive, agricultural management in the region is often linked with nonpoint source nutrient pollution that negatively impacts water quality. Presently, conservation programs designed to install best management practices (BMPs) to mitigate agricultural nonpoint source pollution have not been targeted to those areas of the landscape that contribute disproportionately to surface water quality concerns. We used an innovative spatially targeted conservation protocol coupled with a GIS-based landscape planning tool to evaluate the cost and effect on water quality from nitrate-nitrogen loss under alternative landscape scenarios in an Iowa watershed. Outputs indicate large reductions in watershed-level nitrate-nitrogen loss could be achieved through coordinated placement of BMPs on high-contributing parcels with limited reduction of cultivated land, resulting in improved surface water quality at relatively low economic costs. For example, one scenario, which added wetlands, cover crops, and saturated buffers in the watershed, required the removal of <5% of cultivated area to reduce nitrate-nitrogen loss by an estimated 49%, exceeding the Iowa Nutrient Reduction Strategy goal for enhancing water quality. Annualized establishment and management costs of landscape scenarios that met the nonpoint source nitrogen reduction goal varied from $3.16 to $3.19 million (2017 US dollars). These results support our hypothesis that water quality can be improved by targeting high-contributing parcels, and highlights the potential to minimize tradeoffs by coupling targeted conservation and planning tools to help stakeholders achieve water quality outcomes within agricultural landscapes.
Assuntos
Agricultura , Nitrogênio , Iowa , Nitratos , Qualidade da ÁguaRESUMO
In recognition that Iowa agriculture must maintain long-term production of food, fiber, clean water, healthy soil, and robust rural economies, Iowa recently devised a nutrient reduction strategy to set objectives for water quality improvements. To demonstrate how watershed programs and farmers can reduce nutrient and sediment pollution in Iowa waters, the Iowa Water Quality Initiative selected the Boone River Watershed Nutrient Management Initiative as one of eight demonstration projects. For over a decade, diverse public, private, and non-profit partner organizations have worked in the Boone River Watershed to engage farmers in water quality management efforts. To evaluate social dynamics in the Boone River Watershed and provide partners with actionable recommendations, we conducted and analyzed semi-structured interviews with 33 program leaders, farmers, and local agronomists. We triangulated primary interview data with formal analysis of Boone River Watershed documents such as grant applications, progress reports, and outreach materials. Our evaluation suggests that while multi-stakeholder collaboration has enabled partners to overcome many of the traditional barriers to watershed programming, scale mismatches caused by external socio-economic and ecological forces still present substantial obstacles to programmatic resilience. Public funding restrictions and timeframes, for example, often cause interruptions to adaptive management of water quality monitoring and farmer engagement. We present our findings within a resilience framework to demonstrate how multi-stakeholder collaboration can help sustain adaptive watershed programs to improve socio-ecological function in agricultural watersheds such as the Boone River Watershed.
Assuntos
Parcerias Público-Privadas , Melhoria de Qualidade , Qualidade da Água , Agricultura/economia , Agricultura/métodos , Conservação dos Recursos Naturais/economia , Poluição Ambiental/prevenção & controle , Iowa , Rios/química , Solo/químicaRESUMO
The impacts of strategically located contour prairie strips on sediment and nutrient runoff export from watersheds maintained under an annual row crop production system have been studied at a long-term research site in central Iowa. Data from 2007 to 2011 indicate that the contour prairie strips utilized within row crop-dominated landscapes have greater than proportionate and positive effects on the functioning of biophysical systems. Crop producers and land management agencies require comprehensive information about the Best Management Practices with regard to performance efficacy, operational/management parameters, and the full range of financial parameters. Here, a farm-level financial model assesses the establishment, management, and opportunity costs of contour prairie strips within cropped fields. Annualized, depending on variable opportunity costs the 15-year present value cost of utilizing contour prairie strips ranges from $590 to $865 ha(-1) year(-1) ($240-$350 ac(-1) year(-1)). Expressed in the context of "treatment area" (e.g., in this study 1 ha of prairie treats 10 ha of crops), the costs of contour prairie strips can also be viewed as $59 to about $87 per treated hectare ($24-$35 ac(-1)). If prairie strips were under a 15-year CRP contract, total per acre cost to farmers would be reduced by over 85 %. Based on sediment, phosphorus, and nitrogen export data from the related field studies and across low, medium, and high land rent scenarios, a megagram (Mg) of soil retained within the watershed costs between $7.79 and $11.46 mg(-1), phosphorus retained costs between $6.97 and $10.25 kg(-1), and nitrogen retained costs between $1.59 and $2.34 kg(-1). Based on overall project results, contour prairie strips may well become one of the key conservation practices used to sustain US Corn Belt agriculture in the decades to come.
Assuntos
Agricultura/economia , Conservação dos Recursos Naturais , Modelos Econômicos , Análise Custo-Benefício , Ecossistema , Sedimentos Geológicos , Iowa , Nitrogênio/análise , Fósforo/análiseRESUMO
Residents, developers and civic officials are often faced with difficult decisions about appropriate land uses in and around metropolitan boundaries. Urban expansion brings with it the potential for negative environmental impacts, but there are alternatives, such as conservation subdivision design (CSD) or low-impact development (LID), which offer the possibility of mitigating some of these effects at the development site. Many urban planning jurisdictions across the Midwest do not currently have any examples of these designs and lack information to identify public support or barriers to use of these methods. This is a case study examining consumer value for conservation and low-impact design features in one housing market by using four different valuation techniques to estimate residents' willingness to pay for CSD and LID features in residential subdivisions. A contingent valuation survey of 1804 residents in Ames, IA assessed familiarity with and perceptions of subdivision development and used an ordered value approach to estimate willingness to pay for CSD and LID features. A majority of residents were not familiar with CSD or LID practices. Residents indicated a willingness to pay for most CSD and LID features with the exception of clustered housing. Gender, age, income, familiarity with LID practices, perceptions of attractiveness of features and the perceived effect of CSD and LID features on ease of future home sales were important factors influencing residents' willingness to pay. A hypothetical referendum measured willingness to pay for tax-funded conservation land purchases and estimated that a property tax of around $50 would be the maximum increase that would pass. Twenty-seven survey respondents participated in a subsequent series of experimental real estate negotiations that used an experimental auction mechanism to estimate willingness to pay for CSD and LID features. Participants indicated that clustered housing (with interspersed preserved forest or open space areas), rain gardens, and neighborhood streams with a forested buffer were the features they were most willing to pay for. Participants were not willing to pay for neighborhood streams without buffers. Finally, a spatial hedonic price model using 2093 homes in Ames, IA was used to estimate the effect of public and private open space on housing values. The model indicated that presence of neighborhood association-owned forest and water features as well as proximity to public parks had significant positive effects on housing prices. However, proximity to a public lake had a negative effect on home values. The four methods used in this study include both stated and revealed preference techniques. Although the relative magnitude of value expressed varied, all methods indicated that residents value CSD and LID subdivision features. Subdivision features that included explicit environmental benefits were also consistently preferred over features that did not. Familiarity with alternative designs was an important factor influencing resident willingness to pay for neighborhood features, and developers and civic officials should consider ways to educate citizens about CSD and LID development techniques to increase interest in these designs.
Assuntos
Conservação dos Recursos Naturais/métodos , Reforma Urbana , Planejamento de Cidades , Feminino , Habitação , Humanos , MasculinoRESUMO
Odors emitted from US Midwest hog production facilities present farmers, residents, and state regulatory agencies with a set of complex challenges. To predict odor exposure from multiple swine production sources simultaneously, and to determine siting recommendations for proposed new or enlarged hog facilities, researchers at Iowa State University designed the community assessment model for odor dispersion (CAM). A three-county citizen survey conducted in Iowa examined the level of hypothetical social acceptance of the modeling process, and level of trust in CAM results. While 69 % of respondents approved of modeling as a way to determine the most socially appropriate location for production sites, only 35 % would trust the results if potential odor exposure from a new facility were proposed to be built near their home. We analyzed approval of the CAM model, and level of trust, across a number of demographic, attitudinal, and belief factors regarding environmental quality and the hog industry. Overall, trust in CAM was uneven and varied across respondents. Those residents who would not trust CAM tended to be more concerned with environmental quality and less inclined to believe that the hog industry is critically important economically. Those who would not trust CAM results also had significantly more direct experience with odors. Findings point to predominantly positive, yet equivocal acceptance of CAM results among the citizenry, which is not unexpected given conflict typical of siting decisions in industry and waste disposal arenas. Recommendations are offered regarding the interaction of trust, beliefs and attitudes and the utility of CAM.
Assuntos
Criação de Animais Domésticos , Odorantes , Opinião Pública , Movimentos do Ar , Animais , Coleta de Dados , Feminino , Humanos , Iowa , Masculino , Pessoa de Meia-Idade , Condições Sociais , Suínos , ConfiançaRESUMO
We have developed an add-on tool for use with the Agricultural Conservation Planning Framework (ACPF) that features a multistate financial analysis and field-scale nitrogen (N) reduction tool for use when analyzing different ACPF conservation scenarios. Financial and expected field-scale N loss data are used to calculate total long-term cost and cost effectiveness of various conservation plans. Unique to the ACPF Financial and Nutrient Reduction Tool is the ability to identify individual treatment areas for each practice evaluated, allowing users to create combinatorial conservation planning scenarios drawing from multiple ACPF-identified conservation practices. Financial data account for direct long-term annualized costs for best management practice (BMP) installation and management in Iowa and Minnesota. Opportunity costs of BMPs that retire cropland are spatially determined according to weighted-average crop productivity indices and land rent relationships. The tool quantifies the N requirements for each field, based on 6-yr land-use data, and evaluates the proportion of N likely to be lost from the field as nitrate load via leaching. Financial analyses that can be accomplished by using the ACPF are illustrated in case study watershed scenarios in Iowa and Minnesota. In Iowa, featured scenarios range from 26 to 31% reduction in total nitrate, for a total cost between US$0.580 million and $2.3 million per year, respectively. In Minnesota, example scenarios range from 28 to 51% total nitrate reduction, for total costs of $1.7 million to $2.1 million per year. Tradeoffs in BMP selection related to N reduction outcome and cost are also demonstrated.
Assuntos
Agricultura , Nitratos , Conservação dos Recursos Naturais , Análise Custo-Benefício , Nitrogênio , NutrientesRESUMO
BACKGROUND: The profitability of farming varies based on factors such as a crop's market value, input costs and occurrence of resistant pests, all capable of altering the value of pest management tactics in an integrated pest management program. We provide a framework for calculating expected yield and expected net revenue of pest management scenarios, using the soybean aphid (Aphis glycines) as a case study. Foliar insecticide and host-plant resistance are effective management tactics for preventing yield loss from soybean aphid outbreaks; however, pyrethroid-resistant aphid populations pose a management challenge for farmers. We evaluated eight scenarios relevant to soybean aphid management in Iowa with varying probabilities of aphid outbreaks and insecticide-resistant aphids occurring. RESULTS: Our equation suggests that insecticide use is profitable when the probability of an aphid outbreak is ≥29%, and soybean production will become more costly with increasing probability of pyrethroid-resistant aphids. If farmers continue to use pyrethroids, they will not experience financial consequences from pyrethroid-resistant aphids until the chance of insecticide resistance is 48%. Aphid-resistant varieties provided consistent yield and offered the highest net revenue under all conditions. CONCLUSION: This framework can be used for other crop-pest systems to evaluate the profitability of management tactics and investigate how resistance impacts revenue for farmers. Including the cost of resistance in crop budgets can help farmers and agronomic consultants comprehend these impacts and enhance decision-making to increase revenue and curb resistance development.
Assuntos
Afídeos , Inseticidas , Piretrinas , Animais , Iowa , Glycine maxRESUMO
Farmers face many choices when selecting seed for soybean (Glycine max (L.) Merr.) production, including highly desired herbicide tolerance traits. Despite the convenience of herbicide tolerance, resistant weeds and technology fees may reduce utility and profitability of these varieties, especially when commodity prices are low. Sporadic outbreaks of soybean aphid (Aphis glycines Matsumura, Hemiptera: Aphididae) that require insecticide use for optimal yield can be a further complication for farmers in Iowa. Soybean aphid-resistant varieties are commercially available, but in limited genetic backgrounds without herbicide tolerance. We hypothesized yield and value of resistance traits will vary based on the environment. We established plots at two locations with different risks of soybean aphid outbreaks and used two planting dates at each location to mimic different yield environments. In 2016 and 2017, we planted four varieties that varied in their susceptibility to soybean aphids and glyphosate, and applied insecticides if aphid populations reached an economic threshold. Regardless of genetic background, aphid-resistant varieties prevented populations from reaching the economic threshold at all environments. We observed no significant difference in yield between resistant and susceptible varieties, revealing this trait is as effective at protecting yield as an insecticide application on susceptible varieties at the high-risk location. We also explored the value of each variety in different environments. Resistant varieties produced greater potential net revenue than susceptible varieties at the high-risk location, while the opposite occurred at the low-risk location. Resistant varieties with herbicide tolerance, if made available, would be the most valuable across all environments.