Nutrient management
Nutrient management
UI Extension provides easily accessible information on nutrient management issues specific to Idaho agriculture, such as dairy manure management, Idaho crops (potatoes, small grains, sugar beets, corn, alfalfa, onions, beans, mint and seed crops), irrigation production systems and arid soil environments.
Sustainable dairy grant
The Idaho Sustainable Agriculture Initiative for Dairy (ISAID) grant responds to the critical challenges posed by the exponential growth of Idaho’s dairy industry. Learn more about the grant and our research efforts.
Manure and agricultural waste management
Lagoons
There are two types of lagoons. One is the anaerobic lagoon and the other is the aerobic lagoon. Anaerobic lagoons are earthen containers sized to provide biological treatment and long-term animal waste storage. They are larger than manure storage basins, which do not provide significant biological treatment or long storage periods. On the other hand, anaerobic lagoons are smaller than aerobic lagoons, which are designed to provide a higher degree of treatment with less odor production. Most dairy lagoons are anaerobic. The advantages of anaerobic lagoon systems are:
- manure can be handled hydraulically with water flushing systems, sewer lines, pumps and irrigation equipment
- high nitrogen reduction minimizes the land area required for liquid effluent disposal
- high degree of stabilization reduces odors during land application
- long-term storage at low cost
Related resources
- On-farm comparison of manure application methods in terms of ammonia and odor emissions and costs, 2014
- Interactive effects of copper on alfalfa growth, soil copper and soil bacteria, 2011
Manure compost
Compost is the product of the controlled biological decomposition of organic materials. Composting typically reduces manure volume by 30 to 50%, which makes the material significantly more affordable to transport and provides many other benefits. Composting is a microbial-driven process. Composting could occur in both aerobic and anaerobic conditions. However, aerobic composting is preferred. If provided a suitable environment, the microbes will do the composting work. The most important factors for successful composting are the nitrogen to carbon ratios (the ideal C: N ratio is generally considered to be around 30:1), moisture contents within compost piles (between 50-60%), temperatures (105-160 degrees Fahrenheit), oxygen contents within compost piles (more than 10% is better) and pH levels (5.5-8).
Related resources
- Net nitrogen mineralization from past years' manure and fertilizer application, 2012
- Dairy compost production and use in Idaho: on-farm composting management, CIS 1190, 2012
- Dairy compost production and use in Idaho: the composting process, CIS 1179, 2011
- Dairy manure field applications — how much is too much?, CIS 1156, 2009
Stockpiled manure
Stockpiling is one way of storing solid manure until it can be applied to cropland as fertilizer. The first and most important thing is that stockpiling must follow federal, state and local rules pertaining to manure stockpiling. Two types of stockpiling: short-term (less than one year) stockpiles and permanent stockpiles. General rules for stockpiles state that “they must be located and constructed such that manure-contaminated run-off from the site does not discharge into the waters of the state." As mentioned before, the stockpile must also contain at least 15% solids. This eliminates the possibility of stockpiling true liquid manure.
- Anaerobic co-digestion of dairy manure with potato waste, 2013
- Dairy manure nitrogen availability in eroded and noneroded soil for sugarbeet followed by small grains, 2011
Cultural practices and technologies
Biochar
- Switchgrass biochar effects two aridisols, 2012
- Environmental benefits of biochar, 2012
- Biochar: a synthesis of its agronomic impact beyond carbon sequestration, 2012
- Biochar and manure affects calcareous soil and corn silage nutrients concentrations and uptake, 2012
Conservation tillage
- Evaluation of nitrogen and phosphorus fertilizer placement with strip tillage for irrigated pacific northwest corn production, 2010
- Irrigated small grain residue management effects on soil chemical and physical properties and nutrient cycling, 2009
- Evaluation of strip-tillage and fertilizer placement in southern Idaho corn production, 2008
Cover crops
- Cover crops for high-desert farming systems in Idaho, 2014
- Idaho natural resources conservation service partners expand cover crop technology in Idaho, 2011
Irrigation
- Soil phosphorus dynamics under sprinkler and furrow irrigation, 2014
- Using extension phosphorus uptake research to improve Idaho’s nutrient management planning program, 2012
- Influence of deficit irrigation on nutrient indices in wine grape (vitis vinifera l.), 2012
- Managing runoff water quality from recently manured, furrow irrigated fields, 2010
- Nutrients in runoff from a furrow-irrigated field after incorporating inorganic fertilizer or manure, 2010
- Irrigation-induced erosion, 2007
- Technologies to minimize water quality impacts of irrigated agriculture, 2005
Water and air quality
Water is the lifeblood of Idaho. More than 22 million gallons of water are used in the state each day. More than 97% of this water irrigates 4.1 million acres of farmland. Eighty percent of this water comes from surface sources (rivers and reservoirs); the other 20% is groundwater. Agricultural best management practices (BMPs) to protect water is very important.
Nitrate is the most common groundwater pollutant in Idaho and in the United States. Nitrates in groundwater can originate from many sources, including agriculture, septic tanks, landfills, lawns and gardens, industry and municipalities.
Phosphorus is a common water pollutant in Idaho's lakes and rivers. Phosphorus originates from many sources, including agriculture. Currently, the quality of water used in Idaho is very good compared with water in other areas of the United States and the world.
Nitrogen
Nitrogen is an element essential for all plant and animal life. The interlocking succession of nitrogen reactions occurring in the soil is known as the nitrogen cycle. Agriculture affects both nitrogen additions and subtractions to the soil. Additions include nitrogen fertilizers, crop residues, nitrogen fixation by legumes, and manures. Subtractions attributed to agriculture include crop removal (harvesting), plant uptake and nitrogen leaching.
Federal and state standards dictate that drinking water should not contain more than 10 parts per million (ppm) NO3-N. In rural areas of Idaho, potentially significant sources of nitrogen for groundwater contamination include nitrogen fertilizers, private septic systems, livestock feedlots, barnyards, and legumes used as green manures.
Specific types of BMPs for nitrogen fertilizer management that should be employed in many areas of Idaho include:
- Soil sampling
- Fertilizer recommendations based on research
- Timing of fertilizer application
- Fertilizer placement
- Nutrient credits for legumes and manures
- Nitrification inhibitors
- Manure management
- Irrigation systems management
- Slow-release nitrogen fertilizers
- Crop rotation selection
- Variable fertilizer management
Publications
- Nutrients in runoff from a furrow-irrigated field after incorporating inorganic fertilizer or manure, 2010
- Clinoptilolite zeolite influence on inorganic nitrogen in silt loam sandy agricultural soils, 2010
- Nitrate and groundwater, CIS 872, 2007
- Idaho's nitrate areas of concern, CIS 1099, 2002
Phosphorus
Phosphorus is essential to all forms of terrestrial life. It is widely distributed over the surface of the earth in biologically available forms, cycling within plants, animals, soil and water in the phosphorus cycle. In commercial agriculture, fertilizer is the major phosphorus addition to this cycle.
Water quality problems associated with phosphorus are generally confined to surface waters. Phosphorus in soil is tightly held to soil particles, is immobile, and does not leach. Consequently, contamination of groundwater is rarely a problem.
Many human activities contribute phosphorus to surface waters. Agricultural land enriched with phosphorus by fertilization or manure can contribute substantial amounts of phosphorus to surface waters as the result of runoff and/or erosional processes. Activities associated with modern agriculture often significantly increase soil erosion and water runoff from land and transport sediment into surface waters.
Surface water pollution with phosphorus is controllable — by reducing soil erosion and keeping soil out of creeks, streams, rivers and lakes.
Specific BMPs for phosphorus fertilizer and manure management that should be employed to protect surface water quality in many areas of Idaho include:
- Soil erosion control
- Fertilizer recommendations based on research and soil sampling
- Correct phosphorus fertilizer placement
- Variable fertilizer management
- Efficient manure management
- Barnyard and/or feedlot runoff control
- Conservation tillage and reside management
- Buffer (filter) strips
Publications
- Nutrients in runoff from a furrow-irrigated field after incorporating inorganic fertilizer or manure, 2010
- Environmental implications of inositol phosphates in animal manures, 2007
- Technologies to minimize water quality impacts of irrigated agriculture, 2005
- Removing soluble phosphorus in irrigation return flows with alum additions, 2005
- Percolation phosphorus losses in calcareous furrow-irrigated soils, 2001
Air quality
Air quality issues associated with animal operations include gas (odorous gases, greenhouse gases -GHGs), odor, VOC and particulate matter-PM (PM2.5, PM10 and total suspended particulates-TSP) emissions from animal facilities. While some odorous compounds can cause health problems, odors from livestock are mainly a community or individual perception issue. Many different compounds can be the potential cause of odors from animal operations. These compounds can generally be classified as VOCs, odorous sulfur compounds and ammonia. PM can be emitted directly (i.e., dust) or formed in the atmosphere by the chemical reaction of pollutants such as sulfur oxides, nitrogen oxides, VOCs and ammonia. The major GHGs associated with agricultural operations are carbon dioxide, methane and nitrous oxide.
Ammonia
- On-farm comparison of manure application methods in terms of ammonia and odor emissions and costs, 2014
- Mitigating odors from animal facilities using wood-chip based biofilters, 2008
- Emissions of ammonia, methane, carbon dioxide and nitrous oxide from dairy cattle Housing and manure management systems, 2011
- Measurement of atmospheric ammonia, methane, and nitrous oxide at a concentrated Dairy production facility in southern Idaho using open-path FTIR spectrometry, 2009
- Case study: on-farm evaluation of liquid dairy manure application methods to reduce ammonia losses, 2009
- Case study: seasonal and spatial distribution of ambient ammonia concentrations measured at a large open-lot dairy, 2009
Bioaerosol
- Airborne endotoxin from indoor and outdoor environments: effects of sample dilution on the kinetic limulus amebocyte lysate (lal) assay, 2011
- Ambient endotoxin concentrations and assessment of offsite transport at open-lot and open-freestall dairies, 2011
- Assessment of bioaerosols at a concentrated dairy operation, 2010
- Fate and transport of bioaerosols associated with livestock operations and manure, 2010
- Year-long assessment of airborne endotoxin at a concentrated dairy operation, 2010
- Airborne endotoxin concentrations at a large open-lot dairy in southern Idaho, 2009
- Qualitative and quantitative methodologies for determination of airborne microorganisms at concentrated animal-feeding operations, 2009
- The effect of extraction, storage and analysis techniques on the measurement of airborne endotoxin from a large dairy, 2009
Methane; nitrous oxide
- Emissions of ammonia, methane, carbon dioxide and nitrous oxide from dairy cattle housing and manure management systems, 2011
- Measurement of atmospheric ammonia, methane and nitrous oxide at a concentrated dairy production facility in southern Idaho using open-path FTIR spectrometry, 2009
Soil health and properties
Contact the University of Idaho Analytical Sciences Laboratory to test your soil. It is a full-service laboratory that operates within the College of Agricultural and Life Sciences. They provide the highest quality analytical and research services.
Understanding test results
Alkaline and calcareous soils
- Soil phosphorus dynamics under sprinkler and furrow irrigation, 2014
- Nutrient availability to corn from dairy manures and fertilizer in calcareous soil, 2011
- Biochar and manure affects calcareous soil and corn silage nutrients concentrations and uptake, 2012
- Clinoptilolite zeolite influence on nitrogen in a manure-amended sandy agricultural soil, 2011
- Phosphorus in the calcareous soils of southern Idaho: a literature review with implications for crop production, manure management and water quality, BUL 877, 2011
- Phosphorus mobility in soil columns treated with dairy manures and commercial fertilizer, 2009
- The nature of phosphorus in calcareous soils, 2010
- Percolation phosphorus losses in calcareous furrow-irrigated soils, 2001
Idaho soil map
Regulations
It is intended that nutrient management plans, developed from this standard, be used to help producers improve or maintain their level of management and expertise as it relates to the application of nutrients on the lands they own and/or control.