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- Fact Sheet No. 4 For Dairies j Tables 1 and 2 can be used to estimate the amount oftiitrogeu available to crops from manure produced at a dairy. ]'able I is used to calculate the Animal Units(1,00() lbs each)at the dairy. Tahte 2 is used to estimate the nitrogen loading if the manure is applied to cropland. An alternate and superior way to evaluate the nitrogen loading is to have the holding pond contents and l manure stockpiles analyzed penodically and to then use the reported nutrient values along with the wastewater and manure r application rates to determine the nutrient-loading rate. 1 TABLE l: CALCULATION OF ANIMAL UNITS (AU) A. B. C. I D. E F. [ ANIMAL Factor Freestalls Flushed Corrals Scraped Corrals, I Head AU' Head AU' Head AU' I. Milk Cows 1.0 2. Dry Cows 0.8 TOTAL AU + 3. Heifers(2 years and older) 0.73 Value From 4. Heifers(1 year to breeding) 0.73 B.7 5. Calves(3 months to 1 ear) 0.35 D.7 6. Baby Calves(<3 months) 0.21 F.7 7• Subtotals WIrta TOTAL i Adiustments,for Animal Breed: The AU values above are based on 1,000 pound AU per Title 40 Code of Federal Regulations, Section 122,and can be used directly.for Jersey cows. For Ctuemseys,multiply the AU values by 1.2 before using them.in i Table 2;for Holsteins,multiply the AU values by 1.4 before using them in Table 2 TABLE 2: CALCULATION OF NITROGEN LOADING z Value from Table 1") Liquid Waste Factor Liquid Waste Nitrogen Solid Waste Factor I Solid Waste Nitrogen x 0.8 x 0.45 x 0.25 x 3655Y44F{ . �ry B.1 xU8x011x025x365 1fix, . iy B.7 .- : e�!,�_• s. �- �..� x 0.2 x 0.11 x 0.25 x 365 r_ D.7 x 0.6 x 0.45 x 0.25 x 365 ' 4 r' " w s..dW?. DA - �X 0.6 x D:7 _ 5 -, .r � s � � ` .N x0.4x045x0.25x365 DA - N x04xO11x0.25x365 xOix056 F.1 x 0.25 x 365 4 k�a: _ �- N.- F.1 �":r i a fx� r®R x 0.9 x 0.56 x 0-25 x 365 F.7-F-1 �� x l.0 x 0.45 x 0.25 x 365 �.. Subtotal Increase if wastewater is stored less than 30 days x 2.0 TOTALS(ponds of N) The total pounds of nitrogen as calculated above are the total amount available to crops where the wastewater and solid manure is applied. If solid manure is hauled off-site or wastewater is applied to adjacent property,an adjusted value for Animal Units(AU)are calculated by multiplying the number of Head by the appropriate factor, Tlie following assumptions used in calculating nitrogen values are consistent with assumptions used by staff in Merced County: The arurnals are housed for 365 days/year;the nitrogen excretion rate is 0.56 lbs./Animal Unitlday for milk cows,and 0.45 lbs.lAnintal UniVcfay for other cows;80%and 60%of the manure in freestalls and flushed-corrals,respectively,is handled as a liquid. For milk cows in dry corrals or where alleys are scraped, 10%of the manure is in wastewater at the milk bam- When wastewater held less than 30 days is applied to cropland there is a 50%loss of nitrogen loss,and when wastewater held more than 60 days is applied to cropland,there is a 7.5%loss of nitrogen. There is a 75%loss of nitrogen from storage and application of dry manure. These values arc based on various studies and reports;howeve,,the values may be modified in the future as new information become's available- f - For Guernseys and Holsteins,use adjusted values. � Fs-�4d.doc �5