Chapter 5: Proper Chapter 5: Proper Applications of Waste ProductsApplications of Waste Products

Proper Application of Waste ProductsProper Application of Waste Products

• Proper waste application involves knowledge of the:Proper waste application involves knowledge of the:– waste application systemwaste application system– soils and cropssoils and crops– the required buffers that must be adhered to the required buffers that must be adhered to

• This chapter will explain the required buffers and all This chapter will explain the required buffers and all other factors that must be considered when you are other factors that must be considered when you are trying to determine when and how much animal waste trying to determine when and how much animal waste to land apply.to land apply.

What Buffers Are Required When I Make What Buffers Are Required When I Make Land Applications?Land Applications?

• There are three different sets of buffers you should There are three different sets of buffers you should consider when land applying animal waste:consider when land applying animal waste:– perennial streamsperennial streams– groundwater wellsgroundwater wells– ““good neighbor” buffergood neighbor” buffer

BuffersBuffersPerennial Streams:Perennial Streams:• Under the existing 15A NCAC 2H.0200 Nondischarge Under the existing 15A NCAC 2H.0200 Nondischarge

Rules, you can not land apply animal wastes within 25 feet Rules, you can not land apply animal wastes within 25 feet of perennial streams. of perennial streams.

• Perennial streams are defined as streams indicated by a Perennial streams are defined as streams indicated by a solid blue line on a United States Geological Survey map. solid blue line on a United States Geological Survey map.

• Effective October 1, 1995 for new or expanding swine Effective October 1, 1995 for new or expanding swine farms, you may not apply waste within 50 feet of perennial farms, you may not apply waste within 50 feet of perennial streams. streams.

BuffersBuffersGroundwater Wells:Groundwater Wells:

• A 100-foot buffer is required around wells for:A 100-foot buffer is required around wells for:– location of lagoonslocation of lagoons– other waste treatment facilitiesother waste treatment facilities– land application sitesland application sites

• Even on a properly managed site it is best to maintain Even on a properly managed site it is best to maintain the buffer to reduce the potential for problems. the buffer to reduce the potential for problems.

BuffersBuffers“Good Neighbor” Buffer:“Good Neighbor” Buffer:

• Maintain a minimum distance of 200 feet from any Maintain a minimum distance of 200 feet from any homes or other buildings frequented by people. homes or other buildings frequented by people.

• Do not make land applications on days with Do not make land applications on days with excessive wind. Drift on these days may irritate excessive wind. Drift on these days may irritate neighbors or pollute surface waters.neighbors or pollute surface waters.

Proper Application of Waste ProductsProper Application of Waste ProductsIrrigation Scheduling:Irrigation Scheduling:

• Proper land application of lagoon liquid involves the use Proper land application of lagoon liquid involves the use of water management strategies to best achieve a balance of water management strategies to best achieve a balance between:between:– optimizing the timing of nutrient application to match crop optimizing the timing of nutrient application to match crop

uptakeuptake

– maintaining adequate storage in the lagoon to handle extreme maintaining adequate storage in the lagoon to handle extreme rainfall without overtoppingrainfall without overtopping

– applying water at a rate and amount such that no direct surface applying water at a rate and amount such that no direct surface runoff or percolation below the root zone occursrunoff or percolation below the root zone occurs

Irrigation SchedulingIrrigation SchedulingDecision Making:Decision Making:

• Do I need to irrigate?Do I need to irrigate?

• How much water How much water should I apply?should I apply?

Start

Is the lagoondepth more than thepermanent treatment

volume ?

Is the crop activelygrowing or within30 days of being

planted ?

Do Not Irrigate

Yes

Evaluate lagoon orstorage pond level.

Maintain the requiredstorage at all times

(freeboard plus 25-year,24-hour storm).

Is the groundsaturated or frozen?

Is it raining orexcessively windy?

Has the target plant-available nitrogen

rate for the crop beenapplied ?

No

No Yes

Record the date,location, and amount of

effluent irrigated for eachapplication event.

Irrigate, changing location,after each event.

Obtain a waste analysiswithin 60 days of application.

At least 1 time per year, setor verify irrigation equipment

calibration to apply correctamount without runoff.

No

Yes

Yes Yes

No No

Irrigation SchedulingIrrigation SchedulingDetermining When to Irrigate:Determining When to Irrigate:

• Ask yourself:Ask yourself:– Do I have an actively growing crop (or will a crop be planted or Do I have an actively growing crop (or will a crop be planted or

actively start growing within 30 days)?actively start growing within 30 days)?– Do I have a nitrogen deficit remaining for this crop cycle? Do I have a nitrogen deficit remaining for this crop cycle? – Is the liquid level in my lagoon above the minimum storage depth? Is the liquid level in my lagoon above the minimum storage depth? – Are my land application fields dry enough to be irrigated?Are my land application fields dry enough to be irrigated?– Do I have a waste analysis within 60 days of this irrigation?Do I have a waste analysis within 60 days of this irrigation?

• If the answer to all five questions above is yes, then you If the answer to all five questions above is yes, then you should schedule an irrigation.should schedule an irrigation.

Irrigation SchedulingIrrigation SchedulingBasic Soil-Water Relationships:Basic Soil-Water Relationships:

• SaturationSaturationall soil pores are filled with water and all soil pores are filled with water and conditions are undesirable for good crop growth or conditions are undesirable for good crop growth or wastewater irrigation. wastewater irrigation.

• Field capacityField capacitythe soil has had time to drain away excess the soil has had time to drain away excess water, but still remains in a very moist condition. water, but still remains in a very moist condition.

• Permanent wilting pointPermanent wilting pointplants cannot remove water from plants cannot remove water from the soil.the soil.

Irrigation SchedulingIrrigation SchedulingBasic Soil-Water Relationships:Basic Soil-Water Relationships:

• Gravitational WaterGravitational Watergravitational water is gravitational water is computed as the volume of water in the soil between computed as the volume of water in the soil between saturation and field capacity.saturation and field capacity.

• Plant-Available Water (PAW)Plant-Available Water (PAW)the difference the difference between the water content at field capacity and the between the water content at field capacity and the permanent wilting point. Irrigation should be permanent wilting point. Irrigation should be scheduled to maintain the water content of the soil scheduled to maintain the water content of the soil between these two extremes. between these two extremes.

Irrigation SchedulingIrrigation SchedulingEstimating Soil-Water Content:Estimating Soil-Water Content:

• There are three practical methods of determining if the There are three practical methods of determining if the field is dry enough to be irrigatedfield is dry enough to be irrigatedthese include:these include:

– a subjective method that involves “feeling” the soila subjective method that involves “feeling” the soil

– objective methods utilizing soil-moisture measuring devicesobjective methods utilizing soil-moisture measuring devices

– an accounting approach (checkbook method) to estimate an accounting approach (checkbook method) to estimate soil-watersoil-water

Irrigation SchedulingIrrigation SchedulingDetermining How Much to Irrigate:Determining How Much to Irrigate:

• Irrigation should be scheduled and timed so that:Irrigation should be scheduled and timed so that:

– no surface runoff occurs during the irrigationno surface runoff occurs during the irrigation

– the root zone is not completely saturated at the conclusion the root zone is not completely saturated at the conclusion of the irrigationof the irrigation

– the irrigated water does not leach below the root zonethe irrigated water does not leach below the root zone

Irrigation SchedulingIrrigation SchedulingDetermining How Much to Irrigate:Determining How Much to Irrigate:• The amount of wastewater that can or should be applied during The amount of wastewater that can or should be applied during

any single irrigation cycle is dictated by how much water the any single irrigation cycle is dictated by how much water the soil can “soak up.”soil can “soak up.”

• This varies from day to day and is influenced by:This varies from day to day and is influenced by:– rainfallrainfallwhen and how much it last rainedwhen and how much it last rained– crop maturitycrop maturitywater uptake rate of the cropwater uptake rate of the crop– soil typesoil typetexture, structure, depth, and covertexture, structure, depth, and cover– effective root deptheffective root depth– evapotranspirationevapotranspirationwhich is influenced by temperature, wind, and which is influenced by temperature, wind, and

relative humidityrelative humidity

Approximate Water Infiltration Rates for Approximate Water Infiltration Rates for Various Soil Textures and SlopesVarious Soil Textures and Slopes

Slope0 to 3% 3% to 9% 9+%

inches per hourSands >1.00 >0.70 >0.50Loamy sands 0.70 to 1.00 0.50 to 1.00 0.40 to 0.70Sandy loams and finesandy loams

0.50 to 1.00 0.40 to 0.70 0.30 to 0.50

Loams and silt loams 0.30 to 0.70 0.20 to 0.50 0.15 to 0.30Sandy clay loams and siltyclay loams

0.20 to 0.40 0.15 to 0.25 0.10 to 0.15

Clays, sandy clays, andsilty clays

0.10 to 0.20 0.10 to 0.15 <0.10

Irrigation SchedulingIrrigation SchedulingOperational Considerations:Operational Considerations:

• Discharge rateDischarge ratethe volume of water exiting a the volume of water exiting a sprinkler per unit of time.sprinkler per unit of time.

• Precipitation ratePrecipitation ratenormally expressed as unit normally expressed as unit depth of water (inch) per unit of time (usually hour).depth of water (inch) per unit of time (usually hour).

• Total application volumeTotal application volumecomputed based on the computed based on the amount of time the system operates at a given rate on amount of time the system operates at a given rate on a given field.a given field.

ExampleExample

• If your target application volume to achieve the If your target application volume to achieve the required annual PAN is 3.0 inches, and you should required annual PAN is 3.0 inches, and you should apply no more than 0.5 inch at each irrigation, how apply no more than 0.5 inch at each irrigation, how many times must you irrigate?many times must you irrigate?

• To answer this, use Formula 7:To answer this, use Formula 7:

Number of waste applications needed = total in. (or tons) needed to achieve desired PAN

application volume in. (or tons) application event/

Number of waste applications needed = 3.0 in.

0.5 in. irrigation = 6 applications needed

/

Typical Layout of a Stationary Typical Layout of a Stationary Sprinkler System Sprinkler System

Stationary SprinklersStationary SprinklersDetermination of Precipitation Rate:Determination of Precipitation Rate:

• Determine the discharge rate (sprinkler flow rate) Determine the discharge rate (sprinkler flow rate) and wetted diameter from manufacturer’s literature. and wetted diameter from manufacturer’s literature.

• Determine sprinkler spacing. Recommended Determine sprinkler spacing. Recommended sprinkler spacing is 50 to 65 percent of wetted sprinkler spacing is 50 to 65 percent of wetted diameter.diameter.

• Precipitation rate is then computed using Formula 8:Precipitation rate is then computed using Formula 8:

Precipitation rate (in./hr)= 96.3 sprinkler flow rate (gpm)

sprinkler spacing (ft) lateral spacing (ft)

X

X

Stationary SprinklersStationary SprinklersDetermination of Precipitation Rate:Determination of Precipitation Rate:

• Time of operation is computed using Formula 9:Time of operation is computed using Formula 9:

Time of operation (hr) = application volume (in.)

precipitation rate (in./hr)

Typical Layout of a Traveling Gun Typical Layout of a Traveling Gun Irrigation System Irrigation System

Traveling Gun SprinklersTraveling Gun SprinklersDetermination of Precipitation Rate:Determination of Precipitation Rate:

• Precipitation rate is computed using Formula 10:Precipitation rate is computed using Formula 10:

Precipitation rate (in./hr) = 96.3 sprinkler flow rate (gpm)

3.14 [0.9 sprinkler radius (ft)]

360

w2

X

X XX

Traveling Gun SprinklersTraveling Gun SprinklersDetermination of Application Volume:Determination of Application Volume:

• Application volume is computed using Formula 11:Application volume is computed using Formula 11:

Application volume (in.) = 19.3 sprinkler flow rate (gpm)

lane spacing (ft) travel speed (in./min)

x

x

Traveling Gun SprinklersTraveling Gun SprinklersDetermination of Traveling Speed:Determination of Traveling Speed:

• Traveling speed is computed using Formula 12:Traveling speed is computed using Formula 12:

Travel speed (in./min) = 19.3 sprinkler flow rate ( gpm)

lane spacing (ft) application volume (in.)

x

x

Irrigation System CalibrationIrrigation System Calibration

• Calibration involves collecting and measuring flow at Calibration involves collecting and measuring flow at several locations in the application area. several locations in the application area.

• Any number of containers can be used to collect flow Any number of containers can be used to collect flow and determine the application rate:and determine the application rate:– rain gaugesrain gauges– panspans– plastic bucketsplastic buckets– jarsjars

Irrigation System CalibrationIrrigation System Calibration

• For stationary sprinklers, collection containers should For stationary sprinklers, collection containers should be located randomly throughout the application area be located randomly throughout the application area at several distances from sprinklers. at several distances from sprinklers.

• For traveling guns, sprinklers should be located For traveling guns, sprinklers should be located along a transect perpendicular to the direction of pull. along a transect perpendicular to the direction of pull.

• Set out collection containers 25 feet apart along the Set out collection containers 25 feet apart along the transect on both sides of the gun cart. transect on both sides of the gun cart.

Application Using Spreader EquipmentApplication Using Spreader Equipment

• Wastes that have a higher solids content than can not Wastes that have a higher solids content than can not easily be handled through an irrigation system may easily be handled through an irrigation system may require land application through a pump and haul require land application through a pump and haul system. system.

• The decision process for waste application is more The decision process for waste application is more related to the stage of crop growth and whether the related to the stage of crop growth and whether the crops need nutrient applications. crops need nutrient applications.

Application Using Spreader EquipmentApplication Using Spreader Equipment

• One important issue is the “trafficability” of the fields, One important issue is the “trafficability” of the fields, or how easily your equipment can be operated to or how easily your equipment can be operated to obtain uniform waste application without rutting the obtain uniform waste application without rutting the field or causing soil compaction. field or causing soil compaction.

• Once the decision has been made to perform waste Once the decision has been made to perform waste application, you must be aware of your equipment’s application, you must be aware of your equipment’s waste application rate. This requires the calibration of waste application rate. This requires the calibration of the land application equipment.the land application equipment.

Calibration of Manure SpreadersCalibration of Manure Spreaders

• Applicators can apply manure, bedding, and Applicators can apply manure, bedding, and wastewater at varying rates and patterns, depending on:wastewater at varying rates and patterns, depending on: – forward travel and/or PTO speedforward travel and/or PTO speed

– gear box settingsgear box settings

– gate openingsgate openings

– operating pressuresoperating pressures

– spread widthsspread widths

– overlapsoverlaps

Calibration of Manure SpreadersCalibration of Manure Spreaders

• Calibration defines the combination of settings Calibration defines the combination of settings and travel speed needed to apply manure, and travel speed needed to apply manure, bedding, or wastewater:bedding, or wastewater:– at a desired rateat a desired rate– to ensure uniform applicationto ensure uniform application

CalibrationCalibrationLiquid Manure Spreaders:Liquid Manure Spreaders:

• Spread at least one full load of waste, preferably Spread at least one full load of waste, preferably in a square or rectangular field pattern for ease of in a square or rectangular field pattern for ease of measuring, with normal overlaps.measuring, with normal overlaps.

• Measure the length and width of coverage, Measure the length and width of coverage, recognizing that the outer fringe areas of the recognizing that the outer fringe areas of the coverage will receive much lighter applications coverage will receive much lighter applications than the overlapped areas.than the overlapped areas.

CalibrationCalibrationLiquid Manure Spreaders:Liquid Manure Spreaders:

• Multiply the length by the width and divide by Multiply the length by the width and divide by 43,560 to determine the coverage area in acres:43,560 to determine the coverage area in acres:– Formula 13Formula 13

– Formula 14Formula 14

Coverage area (area of rectangle in ft2) = length (ft) × width (ft)

Coverage area (acres) = length (ft) width (ft)

43,560 ft per acre 2

x

CalibrationCalibrationLiquid Manure Spreaders:Liquid Manure Spreaders:

• Divide the gallons of wastewater in the spreader by Divide the gallons of wastewater in the spreader by the acres covered to determine the application rate the acres covered to determine the application rate in gallons per acre (Formula 15):in gallons per acre (Formula 15):

• Repeat the procedure at different speeds and/or Repeat the procedure at different speeds and/or spreader settings until the desired application rate is spreader settings until the desired application rate is achieved.achieved.

Application rate for spreader (gal or tons acre) = spreader load volume (gal or tons)

coverage area (acres)/