Calibrating manure application equipment is essential. Technology including flow meters, load cells, on-the-go targeted application (e.g., HarvestLab 3000) and other precision ag tools are making calibration easier and less time consuming. Several manual methods can be used to measure spreading rates and uniformity of spread.
Weighing a load of manure and measuring the area that load covers is one method of estimating the rate of application. Solid manure uniformity and rate can be weighed by placing plastic sheets on the ground and extrapolating the measurements to acres or hectares. Liquid manure rate can be estimated by using straight-walled pails for measuring depth of application. These methods require multiple measurements and should consider factors such as overlap, beginning and end of loads, and wind direction. Table 1. Calibrating Manure Spreaders, gives an estimate of application rates based on weight or depth of manure.
Table 1. Calibrating Manure Application Equipment
| Solid Manure Calibration1 | Liquid Manure Calibration2 | |||||
| kg of Manure | Application Rate | Depth of Manure in Pail | Application Rate | |||
| (per sheet) | t/ha3 | in. | mm | L/ha | Imp. | U.S. |
| gal/acre | ||||||
| 0.5 | 3.6 | one tenth | 2.5 | 25,000 | 2,225 | 2,675 |
| 0.9 | 7.2 | one eighth | 3.2 | 32,000 | 2,850 | 3,420 |
| 1.4 | 10.8 | one quarter | 6.4 | 64,000 | 5,520 | 6,845 |
| 1.8 | 14.3 | four tenths | 10 | 100,000 | 8,900 | 10,690 |
| 2.3 | 17.9 | one half | 12.7 | 127,000 | 11,305 | 13,580 |
| 3.2 | 25.1 | six tenths | 15.0 | 150,000 | 13,355 | 16,040 |
| 4.5 | 35.8 | three quarters | 19.1 | 191,000 | 17,000 | 20,420 |
| 6.8 | 53.8 | 1 | 25.4 | 254,000 | 22,610 | 27,160 |
| 1 Using a 122 cm x 102 cm sheet (40 in. x 48 in. plastic feedbag). 2 Using a straight-walled pail. 3 Tons per acre = tonnes per hectare x 0.45. | ||||||
Manure density is impacted by livestock type, bedding, moisture content and how compacted the manure is. Denser manure (e.g., bedded pack beef manure) will be heavier and more compact while less dense dry broiler poultry manure will be less efficient for transport. Table ??, Densities of Different Types of Manure, distinguishes between the densities of different types of manure.
Table 2. Densities of Different Types of Manure
| Manure Type | Weight per Cubic Metre (m3) | Weight per Cubic Foot (ft3) | Weight per Litre | Weight per Bushel |
| Liquid | 1,000 kg | 62 lb | 1.0 kg | 80 lb |
| Semi-solid | 960 kg | 60 lb | 0.9 kg | 76 lb |
| Thick solid | 800 kg | 50 lb | 0.8 kg | 64 lb |
| Light solid | 560 kg | 35 lb | 0.6 kg | 45 lb |
| Dry poultry litter/compost | 400 kg | 25 lb | 0.4 kg | 30 lb |
| 1 bushel = 1.25 cubic feet | ||||
Record Keeping
Record keeping is a key component to many areas of farming and provides the information needed to evaluate and fine-tune management practices. Recording manure application details, such as manure storage capacity or available volume for application, application date, site (field), application rate (planned and actual), equipment and settings, incorporation details, and weather conditions at the time of application are all important for maximizing the potential nutrient value. As part of a crop plan, having soil test values, crop yield and field history and a manure analysis will provide information for where (which field) manure is most economical, potential cost savings in determining additional fertilizer needs, and potentially when selling manure/trading manure may be a economic option. Recording sensitive features (e.g., watercourses, water runs, catch basins, hickenbottom tile inlets, etc.) and application setbacks (that may require additional fertilizer), and other site-specific details could reduce environmental risk.
Record keeping is important from an operational efficiency perspective, but also for regulatory compliance. Even for farms not impacted by the Nutrient Management Act, having records showing weather forecasts ahead of application along with application details can be beneficial for unforeseen events issues or rain events that were not forecast.