Manure Subsurface Drip Irrigation
alternative practice names:
MSDI; Subsurface Drip Irrigation (SDI); Subsurface Drip Irrigation-Effluent (SDI-e); Fertigation
Subsurface drip irrigation (SDI) places water directly below the soil surface, near the root zone of plants, through a network of buried drip tape. SDI uses low-pressure pumps and precision emitters to deliver water, nutrients, and chemicals directly to the plant roots. When farmers can use subsurface drip irrigation systems to deliver manure nutrients to the crop roots, the system is called Manure Subsurface Drip Irrigation (MSDI).
MSDI systems utilize advanced filtration and blend dairy wastewater with fresh water, enabling consistent and reliable application of dairy effluent as a nutrient-rich fertilizer. This technology allows manure to be used as fertilizer in a subsurface drip system, improving water and nutrient efficiency. First, dairy effluent is flushed from the dairy facility to a holding pond/lagoon, then solids are separated, and then the remaining effluent enters an optional secondary/tertiary pond. This effluent is then pumped from the pond/lagoon into the subsurface drip system and blended with fresh water at a variable rate, based on the blend's electrical conductivity (EC), and then filtered through sand media filters. The dairy farmer sets the EC setting to dictate the amount of effluent pumped into the blend. The effluent/water blend is then pushed through a pressurized pipe to the subsurface drip tape in the field to irrigate dairy forage crops. The drip tape can be spaced 30 to 40 inches, about 12 inches below the soil surface.
When used, in what regions in the U.S. is the practice found:
West, Upper Midwest, Southeast
FARM SIZE
When used, typically found on farms of the following sizes:
Over 500 cows
Practice Benefits
Enables operation expansion: This practice improves water use efficiency (WUE), which can help a dairy producer get more crop per drop through precision control, more uniform water distribution, and less surface evaporation. This allows producers to farm more acres in a water-scarce situation.
Increases yields: This system has been shown to increase yield by 5% or more (Zaccaria et al. 2017).
Increases profitability: Increased crop yield can translate to greater profitability.
Improves land value and/or resilience: This system increases resilience by saving water in drought or water-scarce regions, particularly those with no access to or high costs of surface water.
Reduces off-farm input requirements: The system can increase nutrient use efficiency, allowing a dairy producer to apply nutrients to more acres and potentially reduce commercial fertilizer costs.
Pest management: MSDI minimizes weed growth, reduces the need for herbicides, and mitigates the risk of diseases caused by fungal pathogens by avoiding the wetting of foliage.
Higher nitrogen efficiency: When fertilizer and manure are applied below the soil surface, less nitrogen is volatilized, and farmers can reduce nitrogen use; in addition, compared to flood/furrow irrigation which can have uneven or over-application of water, there is less risk of nutrient leaching below the soil surface.
Reduces daily labor: Most systems can be controlled remotely or fully automated; however, they will require more maintenance than traditional above-ground irrigation systems.
Reduces odors: This practice also helps dairies reduce odor from the application of dairy effluent by irrigating below the surface of the soil.
Implementation Insights
Site-specific or Farm-specific requirements
Water availability: The practice will likely not be cost-effective in areas where water costs remain low OR where water allocation is not limited.
Manure collection and handling: The system works best with two lagoons, one as a solids settling basin and the second fed directly into the system. It is also compatible with digesters.
Slopes: Slopes less than 3% do not necessitate special design considerations; slopes greater than 3% require farms to increase the dripline spacing. The environmental and economic outcomes are most straightforward when this system replaces flood irrigation, typically on flat fields.
Acres farmed to animals housed ratio: It is important to evaluate the whole farm nitrogen balance as part of the decision-making process to adopt this practice. Determining the agronomic nitrogen needs of the farmed cropped acres and understanding the amount of nitrogen produced by the cows may influence the best ratio of farmed acres to animals housed.
Lagoon proximity: The forage field should be within three miles of the lagoon.
Additional support: The system requires a power source and supplemental sprinkler/flood irrigation for germination.
Required Capital Expenditures (CapEx)
Primary solids removal: Manure solids can quickly clog the MSDI filtration system. To optimize solids removal and ensure smooth operation, it is advisable to acquire liquid manure from a secondary or tertiary lagoon. Alternatively, farmers can incorporate mechanical separation processes, such as a slope screen, to reduce the solid content in the liquid. Drawing liquid manure from a secondary or tertiary lagoon not only enhances the removal of solid particles but also contributes to the consistency of the liquid manure.
Lagoon flush lines and inlets: Placement of flush lines and inlets within the lagoon is important in order to avoid backflushing solids within close proximity of the inlet. In addition, placing the inlet at the appropriate depth within the lagoon will minimize solids intake.
Electroconductivity sensors: Dairy water's nutrient content varies throughout the year. To manage this, conductivity sensors monitor the salts in dairy water and automatically adjust the fresh-water to dairy-water ratio. The goal is to prevent the buildup of harmful salts.
Filtration system: A filtration system includes sand media filter tanks and sand media. This system will take the blended water and filter it before delivering it to the field. SDI-e systems will need larger filters to remove fine sediments that could clog the emitters.
Variable frequency drive to control a pump by throttling the power up or down based on need. This improves electrical use efficiency and reduces electrical costs, making the system more economical.
PVC pipe: PVC pipe will be used throughout the system as mainline and sub-mains that deliver the blended effluent after filtration to the drip tape in the field.
Drip tape: Drip tape will be installed subsurface in the field at 30- to 40-inch spacing to fertigate the dairy forage crop. Its anticipated lifespan is approximately 10 years.
Sprinklers or flood irrigation system for starting of crop: The farmer must continue maintaining the existing irrigation infrastructure, as MSDI alone cannot support crop germination and early development. Additionally, these systems help manage soil salinity.
Booster pump: Use of a booster pump may or may not be necessary; if necessary, this pump will feed the effluent into the system to blend with fresh water before filtration.
Freshwater holding pond: When farmers' access to water is dependent on the irrigation district schedule, they may want to consider installing a freshwater holding pond. Irrigation districts deliver a set quantity of water on a regular schedule that usually aligns with the needs of those that flood, irrigate, and apply large quantities of water at one time. MSDI will be most effective when the farmer has full control over exactly when and how much they can irrigate.
Required Operational Expenditures (OpEx)
Maintenance and replacement of components: Maintenance expenses include replacing sand media in filters every three to five years, managing lagoons, and drip line replacement approximately every 10 years. The life expectancy of other system components (valves, pipes, pumps, etc.) varies.
Additional labor: Most systems require one or more skilled individuals dedicated to use and maintenance. Where pest damage is severe, additional labor is required to remove rodents and repair lines throughout the growing season.
Implementation Considerations
Maintenance: Implementing this practice requires a shift to subsurface drip irrigation, which requires more maintenance than flood irrigation. Beyond the installation, which typically takes up to 3 months, regular maintenance includes monitoring drip tape to ensure functionality and repairing leaks, lagoon management to ensure solids don’t build up near the system intake, and if automatic flushing isn’t installed, manually flush the tape every other irrigation.
Staffing: MSDI requires additional training as it is controlled via an on-site computer rather than physical valves. Enabling different languages in the computer interface and providing step-by-step manuals for resolving system error codes can improve ease of use.
Management: Pressurized irrigation systems apply water more frequently to meet crop demand without saturating the soil profile. This increases the risk of crop failure if farmers do not closely monitor soil moisture and crop evaporative demand.
Salinity: Salt buildup can make soil unmanageable. To prevent this, farmers can flood the soil with 1+ AF of water annually or biennially to maintain soil productivity.
System maintenance: MSDI systems require meticulous maintenance to ensure optimal functionality.
Limited flexibility: MSDI systems limit flexibility in crop selection and field layout adjustments due to the fixed nature of the underground drip lines.
Drip tape maintenance: Low doses of peracetic acid are recommended to be fed into the system post-filtration during irrigation events to keep lines clean.
Pest issues: Small rodents can destroy MSDI systems by chewing through the lines.
Financial Considerations and Revenue Streams
FEDERAL COST-SHARE PROGRAM
Funding is available for this practice through USDA's Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP).
Related EQIP Practice Standard: Irrigation system, microirrigation (441).
Notes:
Check with the local NRCS office on payment rates and practice requirements relevant to your location.
FINANCIAL RESOURCES, TOOLS, AND CASE STUDIES
Environmental Impacts
REDUCES FARM GREENHOUSE GAS FOOTPRINT
Operations using an MSDI system will observe a large reduction in nitrous oxide emissions compared to a flood-irrigated field. According to Deng et al. (2018), implementing an MSDI system reduces nitrous oxide emissions by 67%. Contributing factors include the incremental additions of manure nitrogen, lower peak soil moisture levels in the surface soil, reduced wetted soil volume, and deeper placement of nitrogen and water delivery.
IMPROVES WATER QUALITY
An MSDI system delivers water directly to the root zone of plants, minimizing surface runoff that can occur when water is applied via traditional sprinkler or flood irrigation systems. This practice will also prevent nutrient leaching from below the root zone by reducing the application of water and manure effluent. When compared to flood-irrigated fields, fields irrigating with MSDI have demonstrated a 44.78% reduction of nitrogen applied per acre (Sustainable Conservation, n.d.)
CONSERVES WATER
Applying water directly to the root zone of plants minimizes evaporation losses from the soil and leaf surface and eliminates surface runoff. In addition, a precision application rate and time reduce losses to deep percolation associated with overapplication.
SUPPORTS BIODIVERSITY
Effective fertilizer and nutrient management coupled with a reduction in the leaching of nutrients off-site contribute to the health of nearby ecosystems. This practice also reduces the need for herbicides and mitigates the risk of diseases caused by fungal pathogens in overly wet foliage.
REFerences
Ayars, J. E., Phene, C. J., Hutmacher, R. B., Davis, K. R., Schoneman, R. A., Vail, S. S., & Mead, R. M. (1999). Subsurface drip irrigation of row crops: a review of 15 years of research at the Water Management Research Laboratory. Agricultural Water Management, 42(1), 1-27.
Camp, C. R. (1998). Subsurface drip irrigation: A review. Transactions of the ASAE, 41(5), 1353-1367.
Alignment with FARM Program
FARM Environmental Stewardship (ES) V2-V3 Alignment
The optional FARM ES Conservation Practice Questionnaire (CPQ) asks about irrigation stewardship methods.
Contents
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
Subsurface drip irrigation (SDI) places water directly below the soil surface, near the root zone of plants, through a network of buried drip tape. SDI uses low-pressure pumps and precision emitters to deliver water, nutrients, and chemicals directly to the plant roots. When farmers can use subsurface drip irrigation systems to deliver manure nutrients to the crop roots, the system is called Manure Subsurface Drip Irrigation (MSDI).
MSDI systems utilize advanced filtration and blend dairy wastewater with fresh water, enabling consistent and reliable application of dairy effluent as a nutrient-rich fertilizer. This technology allows manure to be used as fertilizer in a subsurface drip system, improving water and nutrient efficiency. First, dairy effluent is flushed from the dairy facility to a holding pond/lagoon, then solids are separated, and then the remaining effluent enters an optional secondary/tertiary pond. This effluent is then pumped from the pond/lagoon into the subsurface drip system and blended with fresh water at a variable rate, based on the blend's electrical conductivity (EC), and then filtered through sand media filters. The dairy farmer sets the EC setting to dictate the amount of effluent pumped into the blend. The effluent/water blend is then pushed through a pressurized pipe to the subsurface drip tape in the field to irrigate dairy forage crops. The drip tape can be spaced 30 to 40 inches, about 12 inches below the soil surface.
Practices and technologies
Manure Subsurface Drip Irrigation
alternative practice name:
MSDI; Subsurface Drip Irrigation (SDI); Subsurface Drip Irrigation-Effluent (SDI-e); Fertigation
REGIONALITY
When used, in what regions in the U.S. is the practice found:
West, Upper Midwest, Southeast
COMPARABLE FARM SIZE
When used, typically found on farms of the following sizes:
0 - 100 cows, 100 - 500 cows, 500 - 2500 cows, 2500 - 5000 cows, Over 5000 cows
Practice Benefits
Enables operation expansion: This practice improves water use efficiency (WUE), which can help a dairy producer get more crop per drop through precision control, more uniform water distribution, and less surface evaporation. This allows producers to farm more acres in a water-scarce situation.
Increases yields: This system has been shown to increase yield by 5% or more (Zaccaria et al. 2017).
Increases profitability: Increased crop yield can translate to greater profitability.
Improves land value and/or resilience: This system increases resilience by saving water in drought or water-scarce regions, particularly those with no access to or high costs of surface water.
Reduces off-farm input requirements: The system can increase nutrient use efficiency, allowing a dairy producer to apply nutrients to more acres and potentially reduce commercial fertilizer costs.
Pest management: MSDI minimizes weed growth, reduces the need for herbicides, and mitigates the risk of diseases caused by fungal pathogens by avoiding the wetting of foliage.
Higher nitrogen efficiency: When fertilizer and manure are applied below the soil surface, less nitrogen is volatilized, and farmers can reduce nitrogen use; in addition, compared to flood/furrow irrigation which can have uneven or over-application of water, there is less risk of nutrient leaching below the soil surface.
Reduces daily labor: Most systems can be controlled remotely or fully automated; however, they will require more maintenance than traditional above-ground irrigation systems.
Reduces odors: This practice also helps dairies reduce odor from the application of dairy effluent by irrigating below the surface of the soil.
Implementation Insights
Site-specific or Farm-specific requirements
Water availability: The practice will likely not be cost-effective in areas where water costs remain low OR where water allocation is not limited.
Manure collection and handling: The system works best with two lagoons, one as a solids settling basin and the second fed directly into the system. It is also compatible with digesters.
Slopes: Slopes less than 3% do not necessitate special design considerations; slopes greater than 3% require farms to increase the dripline spacing. The environmental and economic outcomes are most straightforward when this system replaces flood irrigation, typically on flat fields.
Acres farmed to animals housed ratio: It is important to evaluate the whole farm nitrogen balance as part of the decision-making process to adopt this practice. Determining the agronomic nitrogen needs of the farmed cropped acres and understanding the amount of nitrogen produced by the cows may influence the best ratio of farmed acres to animals housed.
Lagoon proximity: The forage field should be within three miles of the lagoon.
Additional support: The system requires a power source and supplemental sprinkler/flood irrigation for germination.
Required Capital Expenditures (CapEx)
Primary solids removal: Manure solids can quickly clog the MSDI filtration system. To optimize solids removal and ensure smooth operation, it is advisable to acquire liquid manure from a secondary or tertiary lagoon. Alternatively, farmers can incorporate mechanical separation processes, such as a slope screen, to reduce the solid content in the liquid. Drawing liquid manure from a secondary or tertiary lagoon not only enhances the removal of solid particles but also contributes to the consistency of the liquid manure.
Lagoon flush lines and inlets: Placement of flush lines and inlets within the lagoon is important in order to avoid backflushing solids within close proximity of the inlet. In addition, placing the inlet at the appropriate depth within the lagoon will minimize solids intake.
Electroconductivity sensors: Dairy water's nutrient content varies throughout the year. To manage this, conductivity sensors monitor the salts in dairy water and automatically adjust the fresh-water to dairy-water ratio. The goal is to prevent the buildup of harmful salts.
Filtration system: A filtration system includes sand media filter tanks and sand media. This system will take the blended water and filter it before delivering it to the field. SDI-e systems will need larger filters to remove fine sediments that could clog the emitters.
Variable frequency drive to control a pump by throttling the power up or down based on need. This improves electrical use efficiency and reduces electrical costs, making the system more economical.
PVC pipe: PVC pipe will be used throughout the system as mainline and sub-mains that deliver the blended effluent after filtration to the drip tape in the field.
Drip tape: Drip tape will be installed subsurface in the field at 30- to 40-inch spacing to fertigate the dairy forage crop. Its anticipated lifespan is approximately 10 years.
Sprinklers or flood irrigation system for starting of crop: The farmer must continue maintaining the existing irrigation infrastructure, as MSDI alone cannot support crop germination and early development. Additionally, these systems help manage soil salinity.
Booster pump: Use of a booster pump may or may not be necessary; if necessary, this pump will feed the effluent into the system to blend with fresh water before filtration.
Freshwater holding pond: When farmers' access to water is dependent on the irrigation district schedule, they may want to consider installing a freshwater holding pond. Irrigation districts deliver a set quantity of water on a regular schedule that usually aligns with the needs of those that flood, irrigate, and apply large quantities of water at one time. MSDI will be most effective when the farmer has full control over exactly when and how much they can irrigate.
Required Operational Expenditures (OpEx)
Maintenance and replacement of components: Maintenance expenses include replacing sand media in filters every three to five years, managing lagoons, and drip line replacement approximately every 10 years. The life expectancy of other system components (valves, pipes, pumps, etc.) varies.
Additional labor: Most systems require one or more skilled individuals dedicated to use and maintenance. Where pest damage is severe, additional labor is required to remove rodents and repair lines throughout the growing season.
Implementation Considerations
Maintenance: Implementing this practice requires a shift to subsurface drip irrigation, which requires more maintenance than flood irrigation. Beyond the installation, which typically takes up to 3 months, regular maintenance includes monitoring drip tape to ensure functionality and repairing leaks, lagoon management to ensure solids don’t build up near the system intake, and if automatic flushing isn’t installed, manually flush the tape every other irrigation.
Staffing: MSDI requires additional training as it is controlled via an on-site computer rather than physical valves. Enabling different languages in the computer interface and providing step-by-step manuals for resolving system error codes can improve ease of use.
Management: Pressurized irrigation systems apply water more frequently to meet crop demand without saturating the soil profile. This increases the risk of crop failure if farmers do not closely monitor soil moisture and crop evaporative demand.
Salinity: Salt buildup can make soil unmanageable. To prevent this, farmers can flood the soil with 1+ AF of water annually or biennially to maintain soil productivity.
System maintenance: MSDI systems require meticulous maintenance to ensure optimal functionality.
Limited flexibility: MSDI systems limit flexibility in crop selection and field layout adjustments due to the fixed nature of the underground drip lines.
Drip tape maintenance: Low doses of peracetic acid are recommended to be fed into the system post-filtration during irrigation events to keep lines clean.
Pest issues: Small rodents can destroy MSDI systems by chewing through the lines.
Financial Considerations and Revenue Streams
FEDERAL COST-SHARE PROGRAM
Funding is available for this practice through USDA's Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP).
Related EQIP Practice Standard: Irrigation system, microirrigation (441).
Notes:
Check with the local NRCS office on payment rates and practice requirements relevant to your location.
FINANCIAL RESOURCES, TOOLS, AND CASE STUDIES
Research
REFerences
Ayars, J. E., Phene, C. J., Hutmacher, R. B., Davis, K. R., Schoneman, R. A., Vail, S. S., & Mead, R. M. (1999). Subsurface drip irrigation of row crops: a review of 15 years of research at the Water Management Research Laboratory. Agricultural Water Management, 42(1), 1-27.
Camp, C. R. (1998). Subsurface drip irrigation: A review. Transactions of the ASAE, 41(5), 1353-1367.
REDUCES FARM GREENHOUSE GAS FOOTPRINT
Operations using an MSDI system will observe a large reduction in nitrous oxide emissions compared to a flood-irrigated field. According to Deng et al. (2018), implementing an MSDI system reduces nitrous oxide emissions by 67%. Contributing factors include the incremental additions of manure nitrogen, lower peak soil moisture levels in the surface soil, reduced wetted soil volume, and deeper placement of nitrogen and water delivery.
IMPROVES WATER QUALITY
An MSDI system delivers water directly to the root zone of plants, minimizing surface runoff that can occur when water is applied via traditional sprinkler or flood irrigation systems. This practice will also prevent nutrient leaching from below the root zone by reducing the application of water and manure effluent. When compared to flood-irrigated fields, fields irrigating with MSDI have demonstrated a 44.78% reduction of nitrogen applied per acre (Sustainable Conservation, n.d.)
CONSERVES WATER
Applying water directly to the root zone of plants minimizes evaporation losses from the soil and leaf surface and eliminates surface runoff. In addition, a precision application rate and time reduce losses to deep percolation associated with overapplication.
SUPPORTS BIODIVERSITY
Effective fertilizer and nutrient management coupled with a reduction in the leaching of nutrients off-site contribute to the health of nearby ecosystems. This practice also reduces the need for herbicides and mitigates the risk of diseases caused by fungal pathogens in overly wet foliage.
Alignment with FARM Program
FARM Environmental Stewardship (ES) V2-V3 Alignment
The optional FARM ES Conservation Practice Questionnaire (CPQ) asks about irrigation stewardship methods.