Category: Statewide

Surface water quality is currently one of the most important environmental issues facing the state of Iowa since the ecological and recreational health of water bodies are threatened by non-point source (NPS) pollution. Many lakes are polluted because of their high concentration of nutrients, often phosphorus (P), which leads to excessive algal growth (eutrophication). To prevent eutrophication, it is necessary to prevent P from entering surface waters or to sequester (make unavailable to algae) the P that is already in the water body. Ferric (Fe3+) and ferrous (Fe2+) iron are known to react with phosphate, leading to precipitates that tie up P. The ferric iron primarily present in hematite can react with P directly, or the iron can be reduced to ferrous iron in anaerobic waters through anaerobic respiration by certain microorganisms present in soils and sediments. This ferrous iron can react with P or can be re-oxidized chemically or biologically back to ferric iron which forms P-sequestering particulate hydrous ferric oxides (HFO). Anaerobic re-oxidation of iron is facilitated by oxidants with a more positive redox potential than the ferric/ferrous couple such as the nitrate/N2 couple. When this occurs, iron oxidation also helps resolve nitrate stimulated eutrophication. An ongoing study of Iowa lakes and wetlands presents an opportunity to investigate the finding that phosphorus found in sediments can be sequestered with iron mine tailings. Specifically, the microbial chemistry involved in the sequestration of P by mixtures of P-laden soils and sediments and iron mine tailings, particularly under anaerobic conditions, will be investigated. The results will assist in formulation of pollution reduction and remediation plans for eutrophic lakes in Iowa and other locations where P is the major pollutant.

Sediment and phosphorus loading of streams are major impairments of surface water sources in Iowa. While production of perennial forages may limit sediment and phosphorus losses in precipitation run-off, sediment and phosphorus loading of streams from stream bank erosion may occur in pastures that are grazed to short sward heights by excessive numbers of cows. Further nutrient loading of streams may result from direct deposition of nutrients in manure. Because sediment and nutrient losses may be limited by maintaining an adequate forage sward height and distribution of manure may be altered by controlling animal movement with fencing or placement of alternative water sources, grazing management may be used to limit nonpoint source pollution of pastures streams. Therefore, an experiment is proposed to 1. Quantify the losses and flow of sediment and phosphorus from stream banks in pastures grazed under different stocking systems; 2. Measure the daily duration of time that cattle occupy locations in streams, along stream banks, and in riparian and upland areas in pastures grazed under different stocking systems; 3. Quantify the frequency that cattle defecate in streams, along stream banks, and in riparian and upland areas in pastures grazed under different stocking systems; and 4. Develop site-specific models of grazing management practices that optimize the quality of stream water and the profitability of pastures in Iowa. Six 30-acre smooth bromegrass pastures that have Clear Creek running through them will be stocked with 18 cow-calf pairs in three grazing management systems: continuous stocking with full access to the stream; rotational stocking (9 paddocks) with full access to the stream within each paddock and alternative water distal from the stream; and rotational (8 paddocks) with deferred (1 paddock containing the stream) stocking with limited access to the stream and alternative water distal to the stream. Paddocks grazed by rotational and deferred stocking will be managed for 50% forage removal and grazed to a 4-inch residual height, respectively. Cattle movement and fecal distribution patterns will be measured monthly on a four (equidistant perpendicular to the stream) by five (in the stream, on the stream bank, and 100, 200 or greater than 200 feet from the stream bank) grid and related to ambient temperature, and forage height and mass. Sediment and phosphorus pollution from stream bank erosion will be measured as the change in length of 5/8-inch fiberglass pins placed 3, 6, 9, and 12 feet from the streams edge in 10 locations in each pasture and the soil phosphorus concentration measured as different soil depths at the initiation of the experiment. Relationships of stream bank erosion to soil surface roughness, forage canopy cover and climatic conditions will be determined. Cow production costs and returns will be determined and used with the sediment and phosphorus losses in optimization models for water quality and economic returns. The results will provide data for the development of water quality plans that consider the benefits of improved grazing management practices and, thus, enhance both water quality and economic returns.

In the mass production of livestock, veterinary antibiotics are extensively used for disease control and growth promotion. One of the major users of veterinary antibiotics is the swine industry. Recent studies have shown that wastewater lagoon samples and ground water samples collected near waste lagoons contained antibiotics at concentrations that may have potential impact on humans and aquatic life. At this time, not much is known about the persistency and accumulative potential of these antibiotics in waste lagoons and in the environment. The objective of this study is to investigate the fate of two commonly used antibiotics, tetracycline and sulfamethazine, in manure lagoons. Batch experiments simulating manure lagoon conditions will be conducted to investigate the sorption of antibiotics onto sludge and the anaerobic biodegradation of antibiotics. The impact of various conditions such as pH, dissolved salts and ammonia concentrations on sorption and degradation will be studied. A direct benefit of the proposed research is an understanding of the fate of veterinary antibiotics in manure management facilities and their impact on surface and ground water.

Sediment fingerprinting via stable isotopes relies upon the premise that the physical and chemical properties of sediment will reflect its provenance. Sediments from different sources in most cases have different organic content (and in some cases different mineralogy) and as a result may exhibit different degree of impact in the receiving waters. The hypothesis in this exploratory research is that stable carbon and nitrogen isotope compositions coupled with measurements of carbon/nitrogen (C/N) ratios can be used to distinguish and quantify sources of sediments when all the factors affecting isotope spatial and temporal variability are considered. The sediment isotope fingerprinting method can be implemented successfully only if two conditions are met:(1) variation between sources must be greater than the variation within, and (2) any modification of the fingerprint due to anthropogenic and in-stream biogenic processes must be accounted for. The objectives of this research are to: (1) distinguish sediment sources by using isotopic ratios of 13C/12C or 15N/14N and atomic ratios of C/N in the Lower Cedar River Watershed; (2) evaluate the spatial and seasonal changes in the sources of sediments; and (3) explore the nature of the chemical and hydrological controls on the sources and composition of sediments.

Movement of water and nutrients though subsurface drainage systems is a concern in many Midwestern agricultural watersheds, including the Des Moines Lobe of Iowa. Although subsurface drainage has its benefits–it improves the productivity of croplands and generally reduces surface water runoff–these systems result in a greater volume of subsurface drainage flow to downstream water bodies, thereby increasing nutrient flow, specifically nitrate-nitrogen, to the same. The increased attention to subsurface drainage systems points to a need to evaluate our ability to model drainage outflow in Iowa. In 1988, a research site in Gilmore City, Iowa was established for studying subsurface drainage from agricultural land. As a result of this study there is a wealth of subsurface flow data to use in calibration and validation of models that simulate subsurface drain flow. The objectives of this investigation are: (1) to evaluate the ability of models to simulate water flow through subsurface drainage systems and (2) to evaluate differences in soil hydraulic properties for the different drainage area plots used for simulation and the impact of varying levels of site-specific soil hydraulic property information on simulated subsurface drainage. The modeling associated with this project will allow for evaluation of drainage systems using a long-term data set (1988-present) in a geographic area of importance (the Des Moines Lobe) in subsurface drainage and nitrate-nitrogen leaching. This research will provide information about factors that need to be considered in modeling subsurface drainage in Iowa, including sensitivity to soil hydraulic properties. Understanding how models perform in simulating drainage flow in an area with significant subsurface drainage and the impact of varying conditions on drainage, would be useful from a research perspective; it would also be useful to practitioners for estimating the outflow from existing systems, designing drainage-system modifications, and predicting the impact of the modifications.

Vegetative filters are a best management practice used for the removal of sediment and other pollutants from overland flow from agricultural watersheds. Although there has been a significant number of vegetative filters installed in Iowa, there is little information about the in-field water quality performance of these systems. The overall vision and goals for this project are to assess current vegetative filters in the state of Iowa to evaluate their effectiveness and educate interested stakeholders on the performance of vegetative filters. This data would be used to analyze the performance of the vegetative filters and investigate whether filter performance can be enhanced through design modifications. Based on this, the objectives of the project, this project will (1) develop educational and assessment tools for evaluating the performance of vegetative filters, (2) identify sites for assessment, (3) educate junior high and high school students on vegetative filter performance and surface water runoff issues related to water quality and biodiversity, and (4) assess the performance of vegetative filters within Iowa using site assessment tools developed and students educated through the project. This project will assist in promoting research, information transfer, and education on water resources and water quality issues in Iowa along with improving the understanding of the processes and impacts of nutrients from agriculture on water quality and the role of sediment on health of lakes and streams.

Many questions related to the impact of current phosphorus (P) management practices on P-related water quality problems are being asked by the public, government agencies in charge of nutrient regulations, producers, and researchers. Because of inappropriate P fertilizer or manure management or the need to dispose of manure, excess P often is delivered from agricultural fields to water resources. For example, the Iowa Department of Natural Resources (IDNR) has established that most Iowa lakes are seriously impaired by elevated P concentrations (Olson and Van Gorp, 2003). The Environmental Protection Agency (EPA) is developing new regulations concerning P levels in lakes and streams. The National Resources Conservation Service (NRCS) and state agencies (such as IDNR) have developed or are developing guidelines for fertilizer and manure management based on P, in addition to existing guidelines based on nitrogen (N). These guidelines are based on P risk assessment tools, often referred to as P indexes. The P index considers a variety of factors that influence P loss from agricultural fields. Although a P index has been developed for Iowa and many other states, the gaps and insufficient information of some processes have created a great deal of uncertainty in some P index components. Two co-investigators of this proposal (Mallarino and Baker) were prominent members of the team that developed the Iowa P index (Iowa NRCS, 2001; Mallarino et al., 2002b).

Excessive addition of nutrients to Iowa surface waters from nonpoint and point sources impairs our waters for beneficial uses, and it also affects down-stream users. Gulf Hypoxia, eutrophication, harmful algal blooms, and impairment of aquatic life are just some of the problems related to runoff of nutrients and sediments into Iowa waterways. To date, we do not have cost-effective ways to monitor all of the States waters and to develop Total Maximum Daily Loads (TMDLs). Also, we do not make effective use of modern sensing and computer technologies to improve our environmental cyberinfrastructure. Recent improvements in such technologies, data mining, and genetic algorithms allow radical improvements in our abilities for real-time sensing of the environment, analysis of the problems, and for evaluation of Best Management Practices or other policy decisions involved with water quality management plans under the TMDL process. The objective of this research is to gain experience with environmental cyberinfrastructure for sensing, modeling, and analyzing nutrient and sediment problems. We will purchase an initial backbone of sensors, data nodes, and access nodes for real-time measurement of gage height, velocity, dissolved oxygen, temperature, conductivity, salinity, pH, turbidity, nitrite, and nitrate. Data will be accessed, stored, and used as input for exercising water quality models (QUAL-2EU and HSPF) in a real-time environment.

Non-point source pollution due to agricultural activities is a vital issue for the State of Iowa. This project will provide a first assessment of the overall impact of a large scale conservation policy that includes several practices simultaneously on the in-stream water quality for all major Iowa rivers outlets. This project will consider the sensitivity of the water quality improvements and costs of the policy under several alternative scenarios, thus evaluating cost-efficiency of alternative conservation plans. Sediment, nitrogen and phosphorus reductions will be estimated. The results from the proposed research project will provide critically valuable information to support effective, science-based water quality management in the state of Iowa. Micro-unit-based economic models and data on land use and conservation practices are combined with a watershed-based hydrological model, the Soil and Water Assessment Tool (SWAT), to estimate the costs of obtaining water quality changes from the hypothetical placement of several broad-based sets of conservation practices. The practices analyzed in the assessment include terraces, grassed waterways, contouring, conservation tillage, land set-aside, and nutrient management strategies. The analysis is carried on 35 watersheds corresponding to the United States Geological Survey 8-digit Hydrologic Cataloging Units that are largely contained in the state. The watersheds correspond to 13 outlets, at which the in-stream water quality is measured. For the cost analysis we consider placing the identified set of practices all across the state. The major objective of the research is to estimate the costs of implementing alternative sets of identified conservation practices together with the reductions in sediment loadings, nitrogen, and phosphorus at the 13 outlets.

Animal production systems are becoming larger, and the public is concerned about the impacts of large animal facilities on water quality. Of particular concern are losses of nitrogen (N) in the forms of NH4-N, NO3-N, phosphorus (P) as PO4-P, pathogens, and antibiotics with surface runoff and subsurface drainage water. The proposed study deals with assessing the effect of land application of swine manure on NO3-N, PO4-P, bacteria, and antibiotic losses in surface runoff and subsurface drainage water. In 2000, with funding from the Leopold Center, a six-year (20002006) field study was initiated at the Iowa State University Northeast Research Center near Nashua to investigate the impact of land application of swine manure on water quality. The specific objectives of this study are: i) to determine the impact of recommended rates of swine manure, based on N and P uptake requirements of crops, on water quality; ii) to study long-term effects of over-application of swine manure on NO3-N, PO4-P, and bacteria leaching to shallow groundwater; and iii) to study the effects of spring and fall injection methods of swine manure on crop yields and NO3-N, PO4-P, and bacteria concentrations in surface runoff and shallow groundwater. From 2000 to 2003, we did not monitor the concentration of antibiotics in surface runoff and subsurface drain water. In 2004, a renewal grant proposal was submitted to the Leopold Center to continue this study for three more years as we needed to collect six years of water quality data for corn-soybean production system. In this renewal grant we proposed that we should collect data on antibiotics in the surface runoff and subsurface drainage water. The Leopold Center decided not to fund this project as the Leopold Center priorities changed to other areas. This was the first time since 1988 that the water quality research project for the Nashua site was not funded by the Leopold Center. Therefore, we requested the National Manure Management Center (NMMC) at North Carolina State University to fund this proposal and include the monitoring of antibiotics in surface and subsurface drainage water in addition to N, P, and bacteria. The NMMC funded this project for 18 months until December 2005 to analyze drainage water samples for antibiotics in objective (ii) in addition to NO3-N, PO4-P, and bacteria. The NMMC was funded with a USDA grant and this USDA grant will end on Dec. 31, 2005, thus, closing the NMMC permanently. With this proposal, we are requesting the ISWRRI to fund this project for the remaining 18 months (January 2006 to June 2007) so that this ongoing study can be completed and final conclusions of various treatments can be drawn to benefit the producers. This study site has 36 one-acre plots, with complete surface and subsurface drain monitoring system (Kanwar et al, 1999). The state-of-the-art surface runoff water and tile water monitoring facilities were installed at this site in 1988 on each of these 36 plots for sampling tile water for various water quality parameters. In 2000, nutrient management treatments were established on these plots (Table 1). These treatments include the application of swine manure to meet N and P uptake needs of corn and soybeans. Also, a new treatment was introduced in this study to apply swine manure at double the P uptake needs of corn to determine the effect of excessive application of swine manure on water quality. In addition to rate effects, manure was applied in the spring and fall to study the effect of timing of manure application on N and P leaching. Surface and subsurface drain water samples are analyzed on a weekly basis for various water quality parameters when tile drains are flowing. Five years of water quality data have been collected and we need one more years data to make final conclusions of this study. Therefore, funding from the ISWRRI for the next 18 months would be critical to the success of this project. At present, we do not have any other source of funds to complete this study.