Manure Utilization Area is the third part of the Site Considerations article series. The focus of this section is to determine what application practices and conditions should be considered to maintain water quality. Since this section looks at management practices rather than structural practices, animal producers or manure applicator can more easily adjust his/her operation to fit within these guidelines.
The first part of a sound manure management program is knowing and planning for manure nutrient recycling. This will ensure that nutrients are fully utilized reducing the potential for manure moving off-site. To evaluate available acres, work through a nutrient management plan for all fields with a growing crop. A nutrient management plan will quantify total nutrients needed which you can match with available manure nutrients produced on your farm. Book values for animal manure are available through the Midwest Plan Service 18 or the Ohio Livestock Manure Management Guide Bulletin 604 produced by Ohio State Extension. To “fine-tune” available manure nutrients, take a manure sample. Make sure it is well agitated if coming from a liquid storage facility. Refrain from pulling samples from the outside layer of stockpiled manure. The Ohio State University is currently working on a nutrient plan called the Nutrient Management Workbook. Through this, producers can fully utilize nutrients across all fields based on crop needs and yield goals. Look for this workbook to be available this summer.
Developing a nutrient management plan will help allocate all nutrients, and if it is approved, can help protect producers from complaints, provided the approved plan is being followed. If there are not enough acres available, there are a few options available. The most desirable solution would be to have more acres under the control of the farm minimizing the risk of sufficient acres available for nutrient recycling.. Renting more acres is also an option but is more volatile than owning land. An opportunity that is becoming more popular is selling manure to row crop producers in close proximity of your operation. Those operations that are looking for ways to cut down on input costs are finding manure is an excellent alternative. This is another reason to get a manure analysis. End users of manure want some assurance of the nutrients they are getting. It will also help determine the value of the manure.
Along with knowing what is being put onto the field, one should also understand the characteristics of the field as well. One of these characteristics is the slope of the cropland. Applying manure to fields with slopes greater than 6% increases the chance manure will reach water supplies during run-off events. If the sloped field is in hay or high residue cover, then the risk is reduced. If at all possible, utilize fields with flatter landscapes for manure application, or implement additional precautions to keep nutrients in the root zone.
Soil tests should also be taken every three years on fields receiving animal manure to document soil nutrient levels. If nutrients levels are increasing over time, you will want to re-evaluate your current nutrient program. On the other hand if you are under applying, it is likely the crop is not reaching its yield potential. Both of these situations can be costly, either through under utilized nutrients or lost yield. A concern facing water quality is phosphorus entering the system. The application of phosphorus, from manure or commercial fertilizer, should be monitored so levels are adequate for the crop being raised. Additional precautions are recommended when soil test levels approach 200-300 lb/ac P2O5 (see OSU Bulletin 604 or NRCS Practice Standard 633).
Artificial drainage is helpful in controlling water in the fields and can help prevent losses due to standing water. Unfortunately, it can also be a direct route for nutrients to water sources. Manure applications are also susceptible to downward movement to subsurface drains and drain outlets should be monitored during application. Control structures can be used to manage these outlets and tile plugs are a means of minimizing or stopping an unwanted discharge. Tile outlets can be an easy source of complaints. Also, it is not recommended to apply manure on fields located within a floodplain during flood season.
Lastly, crop rotation is an important part of any farming operation. Diversifying crops will reduce the risk of disease and pest infestations as well as allow more options for manure applications. With differing nutrient needs and ground cover (e.g. forages, residue, and cover crops), options for nutrient applications will be greater which will aid in the reduction of nutrient loss and the improvement of water quality.
The guidelines and suggestions on manure utilization can be applied to any farm without much difficulty or cost to the producer. Following these guidelines will reduce the risk of receiving complaints based on misapplication and improve the farm’s productivity and financial situation. Developing a sound nutrient management plan is key to productively recycling manure nutrients and ensuring a successful application. To see a complete version of the Site Considerations visit oema.osu.edu/OEMAPublications.htm and click on the first link Site Considerations for Production Facilities.
