The total output of poultry manure from a given farm or complex can be estimated. From this information, the amount of manure that needs to be moved or used can be determined. Table 1 outlines the fresh manure output of several types of poultry. The total manure that will likely be produced can be calculated from this data. Keep in mind that cage layer manure in well-ventilated houses will lose moisture and the actual output of manure may be one third of that shown in the table. On the other hand, the total amount of used litter to be removed from the floor in a broiler or turkey growing house after the flock is sent to market is the manure output shown in Table 1 plus the original litter material adjusted for moisture changes. In either case, the amount of manure or used litter accumulated over a year's time is quite surprising. While the total amount of manure represents a material handling problem, the composition of manure determines where and how much of it can be utilized.
Another way to estimate manure output from the flock is to calculate it from the flock's feed intake. The relationship of feed intake to fresh manure output is shown in Table 1. The weight of fresh manure output is about 115 percent of the total dry feed intake. Total the flock's feed consumption records, and multiply it by 1.15 to get an estimate of fresh manure output. If the accumulated manure represents more than one flock, the feed records of all flocks must be added together before the calculation is made.
|Table 1 How much manure does a poultry flock produce?|
|Type of Poultry||Daily Feed Intake|
(per 100 birds)
|Daily Fresh Manure Output* |
(per 100 birds)
|Laying Chicken||20-26 pounds||20-34 pounds|
|Growing Broiler at 6 weeks of age||26-30 pounds||30-35 pounds|
|Growing Large Tom Turkey at 16 weeks of age||93-115 pounds||108-132 pounds|
|*Fresh manure will contain 70 percent to 80 percent moisture.|
Remember that fresh manure is 75 percent water and the moisture will evaporate from the accumulating manure while it is in the poultry house. Hence, if drying conditions in the house have been very good, only about one third of the calculated weight of the fresh manure will remain, reducing both the amount of manure to be spread on the cropland and the amount spread per acre.
The content of major fertilizer elements in fresh manure is shown in Table 2. These elements are concentrated in the manure when it dries and are diluted when the manure is mixed with litter in floor pen operations. The nitrogen content of the manure behaves differently. The nitrogen is lost as it becomes ammonia gas over time. These losses of nitrogen take place at different rates depending on temperature, moisture, pH, and bacterial activity. For these reasons, fresh manure or manure treated to avoid large nitrogen losses has a higher fertilization value. Rapid drying of fresh manure does help to preserve its nitrogen content. The use of superphosphate in manure to prevent nitrogen losses by reducing pH is not usually recommended because the added phosphorus is not necessary or desirable when poultry manure is used as a fertilizer.
The calcium content of poultry manure is also shown in Table 2. Manure from egg laying chickens is higher in calcium than manures resulting from growing broilers or turkeys. The higher calcium levels of manure from laying chickens used as fertilizer may interact with "liming" practices since both supply substantial amounts of calcium to the soil.
|Table 2 What does freshly voided poultry manure contain?|
|Component or Element||Laying Chicken||Growing Broiler||Growing Turkey|
|Phosphorus as P2O5||0.8-1.2%||0.9-1.2%||1.0-1.4%|
|Potassium as K2O||0.5-0.7%||0.5-0.8%||0.5-0.8%|
|*Nitrogen is lost from poultry manure as ammonia (with time).|
|Storage of manure will therefore result in loss of some nitrogen content.|