Manure 101: Nutrient Management and the Dairy Industry. Kevin Erb UW-Extension NPM Program University of Wisconsin - Extension UW-Madison College of Agricultural & Life Sciences

Farmer View of Site-Specific Future Manure Regulations

What is Nutrient Management? Common Sense. Combine on-farm nutrient sources, with commercial fertilizer, to meet crop need. On-farm nutrient sources (manure) This slide defines nutrient management. Goals are to balance phosphorus (P) and potassium (K) applications with crop needs and to minimize losses to the environment. Soil reserves Commercial fertilizer Minimize nutrient losses

Environmental Aspects of Manure Nutrients Nitrogen Phosphorus Potassium Bacteria/Pathogens BOD

Nitrogen Groundwater Concerns Hypoxia EPA Standard: 10 ppm Blue Baby Syndrome Hypoxia

Hypoxia A new N threat to water quality has recently developed. This deals with N losses in surface water runoff and the impact of that N on salt water estuaries - specifically the Gulf of Mexico. It is suspected that N from the upper Midwest is being carried via the Mississippi River watershed to the Gulf of Mexico where it is causing the formation of a “dead” or hypoxic zone that is deplete of oxygen. This hypoxia zone is seasonal and has been up to 7,000 square miles in size. The result has been devastation of the commercial fishery industry in the gulf. Phosphorus in surface water runoff is a concern with algae blooms and oxygen depletion in freshwater environments (such as those found in Wisconsin). N in surface water runoff is a concern with algae blooms and oxygen depletion in salt water environments

Phosphorus Surface Water Concern Algae Growth

Environmentalist’s view of how farmers manage manure. Is this a public relations problem??? Yes, there IS a manure spreader buried under this pile of manure. The tractor would not start and the farmer kept cleaning the barn. When did he move the tractor?? When the manure finally hit the seat.

Phosphorus Movement Soil attached is most common route 1 lb P = 500 lb algae One ton soil eroded = 1 ton algae in water Stop Erosion, Solve Big Part of the Problem National Buffer Initiative (USA)

Potassium Dairy Animal Health Concern Too Much in Ration: Ketosis / Milk Fever

Bacteria E. Coli Up to 6 month + viable in soil Does not survive as well on surface Enters streams when manure runs off

Antibiotics Animals DO NOT break them down. Excreted intact with the urine Low level resistance concerns

Biochemical Oxygen Demand * A measure of how much oxygen is removed from a water body by the bacteria breaking down organic materials. (BOD) Chemical Oxygen Demand (COD) * Oxygen required to break down chemical compounds in water body.

Manure Basics What is Manure? Urine, feces Waste feed Parlor water Gray water (sinks, etc)

Manure Basics How Much Manure Does a cow produce in a day? A week? A Month? A Year?

The Influence Of Milk Production On Daily Manure Production This graph illustrated the point made on the previous slide. The graph’s data are from informal field observations by Paul Kivlin, Nutrient and Pest Management Program. For those with experience in determining manure production estimates for a dairy herd, it is fairly obvious that milk production (as measured by rolling herd average – RHA) has an influence on the amount of manure generated. The reference most commonly used, “Livestock Waste Facilities Handbook, Midwest Plan Service Technical Bulletin #18”, refers only to animal weights when calculating dairy manure production. It states a daily manure production value of 120 lbs/cow/day for a 1,400 lb animal. The data presented here are a result of information gathered while calibrating manure spreaders throughout northwestern Wisconsin. The data are not presented as controlled research, but may provide insight concerning the link between increased manure production and increased milk production. This information was gathered from 60 daily haul dairy farms and resulted in a correlation between milk production and daily manure production of 0.89.

How Much Manure? Typical Dairy Cow: 148 lbs/day (18 gal) 1036 lbs/week (124 gal) 4440 lbs/month (531 gal) 54020 lbs/year (6460 gal) Does not include youngstock, other wastes

Rule of Thumb #1 One cow plus replacement plus wastewater = 10,000 gal/year

What is in manure? Nutrients Nitrogen, Phosphorus, Potassium Micro nutrients (Sulfur, Boron, etc) Whatever the cow eats that does not become milk or meat becomes manure. If it’s in the feed, it’s in the manure.

Dairy Diet and Runoff Manure from 2 rations applied 1.28 and 0.48% P (rec is 0.34-0.38) Runoff was 4x higher for high P diet Same lbs P applied Runoff was 10x higher when manure rates were the same. Ebeling et al, 2001

Dairy Diet Impacts Ave P in dairy ration is 0.47% Gunderson, Keuning & Erb, 2001 NRC Recommendation is 0.32-0.38% P Higher rates are due to belief that lower P reduces reproductive efficiency.

The Manure Paradox Crops use N:P:K in a 3:1:2 ratio Dairy manure is a 1:1:2 ratio (available) Meet the crop’s N need = excess P Meet the crop’s P need = buy N fert

Manure Nutrient Content - Dairy - _____________________________________ N P2O5 K2O (surface/incorporated) ______________________ Solid (lb/ton) 3 / 4 3 8 Liquid (lb/1,000 gal) 8 / 10 8 21 These are “book value” averages based on the average nutrient content of numerous manure samples submitted to soil testing labs for analysis. Note the one-to-one relationship of nitrogen (N) and P nutrient contents. These values are the AVAILABLE nutrient content of manure - not the TOTAL nutrient content. Remember from workshop one that 60 to 70% of the nitrogen in manure is lost. P losses are estimated to be 45% (or 55% of the P in manure is available); K losses are estimated at 25% (or 75% available).

Crop Nutrient Removal N P2O5 K2O - - - - - - - - - lb/a/yr - - - - - - - - Corn (160 bu/a) 160* 60 40 Corn silage (23 ton/a) 225 90 170 Soybean (40 bu/a) 115 35 40 Alfalfa (5 ton/a) 250 65 250 Reed canarygrass 250 125 325 (5 ton/a) Notice the relationship between N and P removals for corn. The corn need for N is almost three times the nutrient need for P. Speaker: This relationship will be discussed in the next slides. *recommended application rate. Note that these numbers vary by state/prov.

Example of P2O5 Recommendations for Corn Yield Goal Soil Test Level bu/a Low Optimum High Ex.High - - - - - - - - - - - - - - lb/acre - - - - - - - - - - - - - - 111-130 65 45 25 0 131-150 75 55 25 0 151-170 80 60 30 0 Table of the P recommendations for corn. Note that as soil test results increase from low to excessively high, the fertilizer recommendation decreases. As the yield goal increases, the recommended fertilizer application rate increases. Speaker: Refer audience to the P and K recommendations tables in the Fast Facts publication. Be certain audience knows where to find this information. The P and K recommended from the soil test report can often be applied via a starter fertilizer application. The minimum recommendation for starter fertilizer (10 lbs N/a, 20lbs P2O5/a, and 20 lbs K2O/a) is included in the P and K recommendations. (Note: the 10 lb amount of N in the minimum starter recommendation is not included in the N recommendations from the soil test report. You may want to save any discussion of starter fertilizer recommendations until later in the presentation. The topic can easily become confusing.

Corn Nutrient Need vs. Manure Nutrient Supply Following a Nitrogen Strategy lb/acre This slide indicates a manure application strategy that meets the N needs of the crop. Dairy manure applied at a 40 ton/acre rate. Notice the P applications in excess of crop need.

Manure Application Rates Nitrogen Strategy Maximum rates P and K in excess of crop need Efficient with time and labor Preferred when land is limited A N-based strategy for manure applications has a number of advantages: 1) It allows for maximum manure application rates. Often in the 40 to 60 tons per acre range. 2) P and K values are built-up in the soil over time 3) This method is the most time-efficient. Manure is applied at high rates to fewer fields. 4) Manure applied at higher rates needs to go to fewer fields.

Corn Nutrient Need vs. Manure Nutrient Supply Following a Phosphorus Strategy lb/acre This slide indicates a manure application strategy that meets the P needs of the crop. Dairy manure applied at a 20 ton/acre rate. Notice the N application is less than the crop’s need. Commercial N fertilizer applications will be required to meet the crop’s N need.

Manure Application Rates Phosphorus Strategy Low rates Need supplemental nitrogen Increased time and labor Need adequate acreage With a P-strategy for manure, the applications rates are lower - - in the range of 10-15 tons per acre. Commercial fertilizer will be required to meet corn N needs. More time is required to apply manure at lower rates to additional fields.

Manure Nitrogen Content Total vs. Available Solid Manure lb N/ton When determining manure nutrient credits, be certain you are dealing with “the available” nutrient content of manure. Manure analysis results are often reported as total and available nutrient content. Not all the nitrogen (or P and K) contained in manure is available for crop uptake, as shown here. Roughly 60 to 70% of the N in manure is assumed to NOT be available to crops.

Soil Test P Changes Slowly Soil buffering capacity The amount of fertilizer needed to change the soil test level by 1 ppm 18 lbs P2O5/acre = 1 ppm change in soil P Time is required to either lower or raise soil test levels. To change soil test P levels by 1 ppm, 18 lbs of P2O5 must be either added or removed from the soil. The point is: it takes time to build-up or reduce soil test P values as the following example will illustrate.

Soil Test P Changes Slowly - Example - Soil test P = 75 ppm (EH) Track draw-down of P over a CCOHHH rotation. This example tracks the change in soil test P values over the course of a 6-year crop rotation where there are NO additions of P of any kind (fertilizer, starter or manure applications) over the length of the rotation. C = corn O = oats H = hay Note that the soil test P value of 75 ppm at the start of this exercise is in the excessively high (EH) range.

Soil Test P Changes Slowly - Example - Soil test P = 75 ppm (EH) Track draw-down of P over a CCOHHH rotation. Corn @150 bu/a removes 55 lb P2O5/a/yr Oats @ 100 bu/a removes 25 lb P2O5/a/yr Alfalfa @ 5 tons/a removes 65 lb P2O5/a/yr Removal of P2O5 over rotation = 330 lbs P2O5 This calculation shows the removal of P by each crop over the course of the 6-year rotation.

Soil Test P Changes Slowly - Example - Soil test P = 75 ppm (EH) Track drawdown of P over a CCOHHH rotation. Removal of P2O5 over rotation = 330 lbs P2O5 Change in soil test P = 330 lb P2O5/18 = 18 ppm P The amount of P removed by the crops over the 6-year rotation is divided by the soil buffering capacity of 18 lbs P2O5 per 1 ppm change in soil test P. The result is a reduction in soil test P of 18 ppm over the course of this 6-year rotation. Remember NO additional P from any source was added.

Soil Test P Changes Slowly - Example - Soil test P = 75 ppm (EH) Track drawdown of P over a CCOHHH rotation. Removal of P2O5 over rotation = 330 lbs P2O5 Change in soil test P = 330 lb P2O5/18 = 18 ppm P The end result over the 6-year rotation with NO P additions is a soil test P value of 57 ppm - - Still excessively high!!! The Point: It took time to build-up soil test P values; it will take time to draw them down as well. Soil test P = 57 ppm (EH) after the 6-year rotation. (75 ppm P - 18 ppm P = 57 ppm P)

Regulations 1972 Clean Water Act Point vs. Non-Point Sources Problem Not Yet Solved. In addition to commercial fertilizers, P and K are also supplied by manure applications to cropland. Soils naturally release some P and K that is available for plant uptake. Often this needs to be supplemented with additional nutrients for optimum crop production. Nutrient supplying capacity of the soil varies among different soil types. The only way to determine this contribution is with a soil test.

Regulatory Future Each Providence, State, County, Township may be different. Future Lower AU (animal unit) threshold for permit More phosphorus emphasis Future emphasis on bacterial / antibiotics / odor concerns Short term focus will be on P based nutrient management

Economics (Nitrogen @ $0.20/lb) 100 Cow Dairy Alfalfa N = $ 1,200 (50 acres/yr @ 120 lbs N/a) Manure N = $ 1,320 (22 tons/cow/year @ 3 lbs N/ton) Total On-Farm N = $ 2,520 This is an example of the N fertilizer value of the manure and legumes generated on a 100 cow dairy farm. Assumptions: 1) 50 acres of hay rotated annually. Stand density of 30-70% at time of plow-down. N credit = 120 lbs N/a. 2) Manure from milking cows only. Each cow produces 22 tons of manure per year. Manure is surface applied; therefore, N content is 3 lbs N/ton. All manure is collected. 3) Value of N is $0.20/lb. This is a basic N assessment which is what we will do for your farm at the end of this program. Note to speaker: You may wish to substitute other livestock species for this slide depending on your audience. Beef, swine , and poultry versions of this table are available in the CD’s miscellaneous folder. Don’t go over the calculations with audience at this time, but for your knowledge….. Legume N calculation: N credit for a stand of these characteristics is 120 lb N/a 120 lb N/a * 50 acres = 6,000 lbs N 6,000 lbs N * $0.20/lb N = $1,200 value of N from alfalfa Manure-N calculation: 100 cows * 22 tons/cow/yr * 3 lbs N/ton of manure = 6,600 lbs N 6,600 lbs N * $0.20/lb N = $1,320 value of the N from manure.

Economics (P2O5 @ $0.25/lb; K2O @ $0.13/lb) 100 Cow Dairy Manure P2O5 = $ 1,650 (22 tons/cow/year @ 3 lbs P2O5/ton) Manure K2O = $ 2,288 (22 tons/cow/year @ 8 lbs K2O/ton) Total Manure P205 & K2O = $ 3,938 This is an example of the P and K fertilizer value of the manure generated on a 100 cow dairy farm. Assumptions: 1) Manure from milking cows only. Each cow produces 22 tons of manure per year. Manure-P content is 3 lbs P2O5/ton; K content is 8 lbs K2O/ton. All manure is collected. 2) This example assumes every available pound of P and K in manure has value. In reality soil reserves of P and K on most farms are high enough to supply all or most of the crop’s P and K needs. If such is the case, the economic value of manure-P and -K would be reduced. Note to speaker: You may wish to substitute other livestock species for this slide depending on your audience. A beef, swine , and poultry version of this table is available in the CD’s miscellaneous folder. Don’t go over the calculations with audience at this time, but for your knowledge … Manure-P calculations: 100 cows * 22 tons/cow/yr * 3 lbs P2O5/ton of manure = 6,600 lbs P2O5 6,600 lbs P2O5 * $0.25/lb P2O5 = $1,650 value of the P2O5 from manure. Manure-K calculations: 100 cows * 22 tons/cow/yr * 8 lbs K2O/ton of manure = 17,600 lbs K2O 17,600 lbs K2O * $0.13/lb K2O = $2,288 value of the K2O from manure.

If You Are Going To Use Manure as a Fertilizer… Treat It Like A Fertilizer! Commercial fertilizer applications to fields provide nutrients to crops. Manure applications to fields provide nutrients to crops.

Soil Test Phosphorus Variability from a Wisconsin Dairy Farm This graphic illustrates the variability of field soil nutrient levels from a Wisconsin dairy farm. This pattern is typical of Wisconsin livestock farms. Note that soil test P values vary from very low to excessively high across the 12 fields on this dairy farm. The source of this variation can be attributed to manure distribution on the farm. Field 10 is probably next to the barn (hence, a long history of manure applications resulting in elevated soil test P levels) while field 7 is distant from the barn. Parameters on the graph : The green bar is the optimum soil test range for P of the most demanding crop (usually alfalfa) in the rotation.

Public Relations Manure Handling and Application Odor control Real or perceived excessive rates Road spillage Traffic hazards & delays Spreading near water Cattle in water

Challenges of the Future: Dairy Trends. Management: More cows, fewer farms. Realization by farmers that manure management requires a cash investment. Manure’s Internet IPO: Lots of ideas now, lots of broken ideas coming in a few years. Easiest to use / most farm-profitable techniques will remain.

Opportunities of the Future: Every farm will have a nutrient management plan. Nitrogen – Phosphorus Pendulum Affiliated and independent consultants Site-specific research Between 1992 and 2001, UWGB was the lead institution for mass balance research.

Farmers are searching for answers. Manure is no longer considered the last item after everything else is done.

kevin.erb@ces.uwex.edu