Manure isn’t a liability; it’s an asset. As livestock and grain margins narrow for the foreseeable future, producers should start viewing manure with the rose-colored glasses it deserves. Track how much manure is supplied to the crop to account for its tremendous value. Three main factors affect the value from manure – application rate, analysis and placement.
1. Application Rate. Whether applying liquid manure through a dragline or pen-pack solids via a box spreader, the only way to accurately credit manure is by knowing the application rate. The calibration process is fairly straightforward when applying solid manure.
The first step is weighing the application rig to distinguish the weight of manure hauled. Then calculate the area of manure application in acres. The area in acres is calculated by multiplying length by width in feet and then dividing by 43,560.
It’s typically easier to calculate the manure rate for dragline systems versus box spreaders. Custom haulers have a flow-meter in their systems that calculates manure-application rate. Regulations state that flow-meters must be calibrated twice per year. That allows for an accurate estimate of manure rates. The same volume-per-acre calculation can be used to determine the application rate when a flow-meter isn't used. But it will be calculated in gallons per acre rather than tons.
2. Analysis. Once the amount of manure to be applied has been established, determine what’s in the manure. An analysis is the best way to determine its fertilizer value. Proper sampling is critical to accurately reflect the nutrient content. When sampling solid manure, use a push-probe, auger or spade to obtain a representative sample from several locations throughout a manure pile or pack. If the manure is being loaded for spreading, a sample can be obtained by subsampling several spreader loads.
For liquid manure, thoroughly agitate the contents of the storage facility before sampling. It’s best to take a composite sample from five to ten loads. The subsamples should be thoroughly mixed and submitted as one sample.
Submitting a sample to the laboratory is as easy as placing the liquid or solid samples in a pint-size, screw-top plastic container filled to three-quarter capacity. It should be frozen immediately. Solid samples may also be placed in a good-quality freezer bag, but most laboratories have sample kits available. Check with a laboratory or fertilizer supplier first to order supplies. Keep manure samples frozen until shipped or delivered to the laboratory. Mail samples early in the week and avoid mailing over holidays and weekends.
Most standard manure analysis involves moisture, total nitrogen, phosphorus, potassium and sulfur. A comprehensive analysis will likely include the standard analysis specifications plus nitrate, ammonium, organic nitrogen, and pH. Those values are expressed in either pounds per ton or pounds per 1,000 gallons. They’re multiplied by the application rate to determine the amount of nutrients applied.
3. Placement The key to safe and effective manure application is applying it in the right place at the right time. Many states laws indicate where and when manure may be applied. Even if one's operation doesn’t have a nutrient-management plan, it’s in one's own best interest to follow the rules.
The rules exist to limit the amount of manure lost to the environment. Nutrients generally shouldn’t be applied during elevated runoff-risk periods. The upper Midwest’s avoidance window is generally in February and March when snow is melting and precipitation increases.
Surface-water-quality-management areas should also be spared from winter applications. Those are areas within 1,000 feet of a lake or pond or 300 feet away from a stream. Areas close to water create a greater risk of runoff directly into a waterbody.
Soil type is the final factor to consider when applying manure. Soils that have high permeability or are seasonally wet are best reserved for spring-manure application. Since those applications occur near to the crop-use timeline, the risk of loss is reduced. For more information on recommended application rates and timing, refer to your state’s nutrient or manure-application standards.
With just a few simple, yet effective strategies, livestock producers can make the most of their manure. Fine-tuned approaches to application will allow for better use of the valuable fertilizer that’s supplied via manure. By knowing how much, what and where to spread manure, producers can make the most of applications in years with both tight and wider margins.