Location: Northwest Irrigation and Soils Research
2017 Annual Report
Objectives
Objective 1: Assess organic and inorganic fertilizer forms and application methods as management options for reducing greenhouse gas emissions, increasing nutrient use efficiencies, and optimizing crop yields for irrigated western cropping systems.
Subobjective 1A: Identify effects of fertilizer source, timing and nitrification and urease inhibitors on GHG emissions, nutrient cycling, and field scale nutrient budgets.
Subobjective 1B: Identify effects of manure application rate and frequency on GHG emissions, nutrient cycling, and field scale nutrient budgets.
Subobjective 1C: Determine the efficacy of cover crops to reduce offsite transport of soil nutrients in a dairy forage crop rotation receiving manure.
Subobjective 1D: Evaluate N supply and timing effects on corn yields and nitrogen use.
Subobjective 1E: Determine the interacting effects of manure and fertilizer on soil N mineralization.
Subobjective 1F: Determine the effects of manure incorporation method and timing on the emissions of CO2 and N2O from moist soils subjected to diurnal freeze-thaw cycles.
Objective 2: Investigate the occurrence and transport of antibiotic drugs, antibiotic-resistance genes, and antibiotic-resistant bacteria in irrigated western cropping systems to provide baseline data needed to develop mitigation strategies.
Subobjective 2A: Monitor antibiotics in irrigation return waters to better understand their persistence in the environment and potential movement from areas under intensive dairy and crop production.
Subobjective 2B: Conduct an inter-laboratory validation of assays to screen selected antibiotic resistance determinants.
Subobjective 2C: Determine the influence of dairy manure and compost application rate, soil temperature, and soil moisture content on the occurrence of antibiotic resistant bacteria and antibiotic resistance genes in soil.
Subobjective 2D: Evaluate the effect of annual dairy manure applications, as well as crop rotation, on the distribution of antibiotic resistance genes in the soil profile.
Subobjective 2E: Determine the prevalence of antibiotic resistant indicator bacteria and antibiotic resistance genes in plots irrigated with diluted dairy wastewater with and without added copper sulfate.
Objective 3: Improve measurement and prediction of ammonia and GHG emissions and transport from western dairy systems to improve GHG inventories and evaluate the mitigation potential of management practices.
Subobjective 3A: Improve emission factors for NH3 and GHG emissions from western dairy production systems and improve/validate equations and process based models for estimating emissions.
Subobjective 3B: Improve understanding of impacts of NH3 losses on regional air quality.
Approach
Sustainable crop and dairy production requires efficient nutrient use. Modern dairy farms produce more milk with fewer inputs per unit of milk than farms in the past. Crop yields continue to increase with improved genetics and management. At the same time, nutrient losses to the environment can negatively impact air and water quality. This is especially a concern when concentration of animal production increases the amount of nutrients brought into an area. This project addresses environmental and agronomic issues associated with irrigated crop and dairy production. Specifically, the research seeks to increase crop nutrient use efficiency, minimize nutrient losses and greenhouse gas (GHG) emissions, and reduce occurrence and transport of antibiotics and antibiotic resistance bacteria. The long-term goal of this project is to develop tools to predict nutrient budgets, antibiotic resistance and emissions in the dairy farm-crop production system.
Project objectives will be achieved through several ongoing and new studies conducted at different scales to improve our understanding and management of nutrients, ammonia and GHG emissions, and antibiotic resistant bacteria and genes in dairy and crop production. Research for Objective 1 encompasses six studies evaluating effects of commercial fertilizer with and without nitrification and urease inhibitors, dairy manure, dairy manure compost, and cover crops on gas emissions, soil nutrient cycling, and crop nutrient uptake. Objective 2 contains five studies to evaluate the existence, fate and transport of antibiotics and antibiotic resistant bacteria and genes in soils and surface water. Objective 3 will utilize existing and new data to improve and validate established farm system models that predict nutrient cycling and gas emissions.
Progress Report
In support of Objective 1, Measurement of greenhouse gas emissions from alfalfa on the Greenhouse gas Reduction through Agricultural Carbon Enhancement network (GRACEnet) plots continued in 2017, which was the final year of the silage corn-barley-alfalfa-alfalfa-alfalfa crop rotation. These plots have not had any fertility treatments since the alfalfa was planted in 2015 and gas emissions were similar among treatments. The crop rotation will be repeated for the next five years.
The four-year crop rotation on the long-term manure study was completed in 2016. The study will continue with three manure application rates applied annually or biennially for a second four-year term. Measurement of greenhouse gas emissions have been completed for this project. Nitrogen mineralization measurements continued for a fifth year. These values are currently being compared to soil test parameters to develop a general prediction equation for nitrogen mineralization in southern Idaho fields with dairy manure application histories. After four years, the highest manure application rate increased organic carbon in the top 12 inches of soil from 1.5% to 3%, but also increased soil phosphorus concentrations to eight times greater than required for crop production and tripled salt concentrations and sodium adsorption ratio. The higher manure application rates also increased nutrient and salt concentrations in the 12-24 inch soil depth. Higher manure application rates also decreased extractable sugar yield for the 2016 sugar beet crop.
The first year of a study evaluating the effects of manure application, triticale winter cover crop, and tillage on nutrient cycling, crop yield, and crop water use has been completed. Triticale yield in the spring before corn was planted was six times greater from manure-treated plots compared to unfertilized plots. The first year of a study examining the interacting effects of manure and fertilizer on soil nitrogen mineralization was also completed.
Nitrogen fertilizer application rate and timing effects on grain and silage corn yields have been evaluated for six site-years, with the intention of updating corn nitrogen fertilizer recommendations for the Pacific Northwest. This research continued with two additional site-years in 2017.
In support of Objective 2, research was conducted using passive sampling technologies to determine the occurrence of antibiotic residues in irrigation return flow streams of an intensively managed, 200,000 acre agricultural watershed in south-central Idaho. Only 8 of 21 targeted antibiotics were detected at frequencies ranging from 3 to 62%, with monensin having the highest detection rate. Monensin is only used in livestock production and is excreted with feces, thus its detection suggests that a portion of the antibiotics could be entering the return flows during the irrigation season as runoff from manure-treated fields or irrigated pastures. Some antibiotics were also detected in the irrigation canal before water is diverted onto fields for irrigation, indicating that antibiotics in irrigation return flow do not solely come from within the watershed.
Investigations into the presence of antibiotic resistance genes and antibiotic resistant bacteria in agroecosystems are well underway. Molecular methods were developed to detect antibiotic resistance genes in environmental samples. These methods will be used in subsequent years among ARS researchers to perform an inter-laboratory validation study. A microcosm experiment was performed to determine the influence of dairy manure and composted manure on the occurrence antibiotic resistance genes and antibiotic resistant bacteria. A preliminary analysis of the results indicates that there is a direct relationship between the manure and compost application rates and gene/bacteria levels in the soil, while gene/bacteria levels decreased as soil temperature increased. The effect of manure application rate on antibiotic resistance gene levels was also confirmed in the long-term manure study in Objective 1.
Under Objective 3, research has been completed to improve emissions estimates of greenhouse gases and ammonia from liquid storage ponds on western dairy farms. Methane emission data are being used by both Environmental Protection Agency (EPA) and the Intergovernmental Panel on Climate Change (IPCC) to improve emissions estimates for dairy lagoons. Ammonia emissions varied seasonally and were heavily dependent on the physicochemical characteristics of the lagoon, such as total and ammoniacal nitrogen and pH, along with wind speed and air temperature. A nitrogen balance for a small Idaho dairy (280 milk cows) showed that ammonia losses from the lagoon were equal to 65% of the total nitrogen entering the lagoon. The data are being used by EPA to improve estimates of ammonia loss from the livestock production. The data generated in this study have also been used to develop new models for estimating ammonia and methane emissions from dairy lagoons and to improve the Integrated Farm System Model (IFSM) in collaboration with ARS scientists at University Park, Pennsylvania.
Research evaluating the effects of dairy cattle diet on carbon and nitrogen losses during manure storage and after application to soil have been completed. The diets had little impact on manure nutrient concentrations. A soil column study showed higher nitrate concentrations in the top six inches of soil when manure slurry was applied compared to solid manure.
A survey was completed in cooperation with the University of Idaho to identify manure and fertilizer application practices in southern Idaho. Survey information will be used to develop scenarios for simulating nitrogen losses from crop production in southern Idaho (2054-12000-011-03S, "Estimating Nitrogen Mineralization in Irrigated Croplands Receiving Dairy Manure"). An ammonia monitoring station for the Ammonia Monitoring Network (AMoN) was installed in 2017. This station will provide the U.S. network with data from an arid agricultural area.
Accomplishments
1. Improved methane emission estimates from dairy lagoons in the Western U.S. Methane generation from dairy liquid storage systems is a major source of agricultural greenhouse gas emissions; however, there has been little on-farm research conducted to estimate these emissions. ARS researchers in Kimberly, Idaho, measured methane emissions on six dairy farms and determined that emissions from dairy lagoons varied seasonally and were heavily dependent on the volatile solids, total nitrogen, and pH in the lagoon in addition to air temperature and wind speed. Annual methane emissions measured on these farms were twice as much as those estimated using the current Environmental Protection Agency methodologies. An alternative estimation methodology that used a volatile solids degradation factor provided better estimates of methane emissions from dairy lagoons. The improved methodology will provide more accurate estimates of methane contribution from dairy lagoons, which will provide more reasonable estimates for reduction targets.
2. Soil carbon dioxide and nitrous oxide emissions were greater after manure application. Carbon dioxide and nitrous oxide are greenhouse gases and represent lost carbon and nitrogen when emitted from soil. ARS researchers in Kimberly, Idaho, monitored greenhouse gas emissions from a silage corn–barley–alfalfa rotation that received either conventional urea fertilizer in the spring or dairy manure in the fall or spring. Crop yields were similar among treatments. Nitrous oxide emissions were two to three times greater from manure treatments than urea, although less than 0.65% of the nitrogen applied with urea or manure was lost as nitrous oxide. Carbon dioxide emissions were about 1.5 times greater from manure treatments than urea, but only in the years when manure was applied. Dairy manure can produce similar crop yields as urea and increase soil carbon but can also increase greenhouse gas emissions.
3. Manure improves winter wheat yield two years after application. More efficient long-term use of nitrogen from manure is needed to reduce excessive nitrogen losses from crop land. ARS researchers in Kimberly, Idaho, determined that applying compost or manure at greater-than-optimum rates for nitrogen increased winter wheat yield the second year after application. Wheat yields from the compost and manure treatments were greater than achieved with optimal rates of urea fertilizer. Nitrogen concentrations in the soil were also greater, which could lead to nitrogen losses. Applying manure or compost can improve yields for multiple years but can also increase nitrogen losses.
4. Biochar increases soil organic carbon but not always crop yield. Biochar can remediate degraded soils and maintain or improve soil health, but predictable effects on soil properties and crop productivity are unknown. A collaboration between Iowa State University and ARS researchers at six different locations across the U.S. showed that a fast-pyrolysis, hardwood biochar increased soil organic carbon content by 48% in the top six inches of soil across a broad range of temperate soils. However, crop yield responses to biochar should only be expected when specific soil quality problems limit productivity such as limited water or nutrient retention capacity. This research suggests that biochars could be a more effective soil amendment if they were produced to have specific chemical and physical properties to address specific soil problems in addition to storing atmospheric carbon in agricultural soils.
Review Publications
Biswas, S., Niu, M., Appuhamy, J., Leytem, A.B., Dungan, R.S., Kebreab, E., Pandey, P. 2016. Impacts of dietary forage and crude protein levels on the shedding of Escherichia coli O157:H7 and Listeria in dairy cattle feces. Livestock Science. 194:17-22.
Dungan, R.S., Leytem, A.B., Tarkalson, D.D., Ippolito, J.A., Bjorneberg, D.L. 2017. Greenhouse gas emissions from an irrigated dairy forage rotation as influenced by fertilizer and manure applications. Soil Science Society of America Journal. 81:537-545.
Ippolito, J.A., Berry, C.M., Strawn, D.G., Novak, J.M., Levine, J., Harley, A. 2017. Biochars reduce mine land soil bioavailable metals. Journal of Environmental Quality. 46:411-419.
Laird, D.A., Novak, J.M., Collins, H.P., Ippolito, J.A., Karlen, D.L., Lentz, R.D., Sistani, K.R., Spokas, K.A., Van Pelt, R.S. 2016. Multi-year and multi-location soil quality and crop biomass yield responses to hardwood fast pyrolysis biochar. Geoderma. 289:46-53.
Tarkalson, D.D., Bjorneberg, D.L. 2016. Effect of phosphorus placement methods and rates on sugarbeet production under strip tillage in southern Idaho. Crop, Forage & Turfgrass Management. 2. doi:10.2134/cftm2015.0183.
Tarkalson, D.D., Bjorneberg, D.L., Moore, A. 2016. Fall and spring tillage effects on sugarbeet production. Journal of Sugar Beet Research. 52(3&4):30-38.
Tarkalson, D.D., Bjorneberg, D.L., Camp, S., Dean, G., Elison, D., Foote, P. 2016. Improving nitrogen management in Pacific Northwest sugarbeet production. Journal of Sugar Beet Research. 53(1&2):14-36.
Biswas, S., Kranz, W.L., Shapiro, C.A., Bartelt-Hunt, S.L., Mamo, M., Snow, D., Tarkalson, D.D., Shelton, D.P., Mader, T.L., Van Donk, S.J., Zhang, T.C. 2016. Effect of rainfall timing and tillage on the transport of steroid hormones in runoff from manure amended row crop fields. Journal of Hazardous Materials. 324:436-447.
Leytem, A.B., Dungan, R.S., Bjorneberg, D.L. 2017. Spatial and temporal variation in physicochemical properties of dairy lagoons in south-central Idaho. Transactions of the ASABE. 60(2):439-447.
