How far can I afford to haul my manure?

When debating the economics of manure there are many things that can be considered, whether it be costs associated with manure collection in the barn, building or maintaining the manure storage, or moving the manure to the field and land applying it. How these costs are accounted for can make a big difference in whether we think the manure is providing a cost effective fertilizer resource, or if its use doesn’t pencil out compared to commercial fertilizers.

In evaluating the costs of manure application, the first choice a farmer has to make is whether to hire a commercial manure applicator to apply the manure for them, or to perform the application themselves. There are numerous reasons to consider both options, whether it be the ease of allowing someone else to handle the application, bio-security issues of bringing different equipment onto your farm, control over when manure application occurs, costs, or availability of equipment and labor. Here I'm going to base my cost estimates on information on what our commercial applicators are charging and use this to get some rough estimates. This is meant to be illustrative only, not an analysis for any particular farm.

When using manure as a fertilizer one of the most common questions is, how far can I afford to haul it and still have it be a viable, cost-effective fertilizer? What this question usually means is how far can I transport the manure and still have it be cheaper to use than commercial fertilizer. Like most thing in life, it depends. Things like what the nutrient content of the manure is, which nutrients are we getting value from (nitrogen, phosphorus, potassium, trace minerals, or even organic matter), what sort of crop rotation are we using, or even whether we are applying it ourselves or hiring a custom applicator to apply it can all impact the results. In addition, current prices of commercial N, P, and K fertilizers can affect this distance as this sets the value on the nutrients in our manure.

Let’s look at an examples; we are going to work with corn-soybean rotation, set current nitrogen, phosphorus, and potassium prices at $0.44 per lb N, $0.49 per lb P2O5, and $0.40 per lb K2O, and focus on swine manure first. Current nutrients concentrations (average ± standard deviation) in deep-pit slurry from a swine finishing operation are around 58 ± 25 lbs N/1000 gallons, 18 ± 8 lbs P/1000 gallons, and 20 ± 7 lbs K/1000 gallons (average ± standard deviation). Our commercial manure haulers on average are charging  around $0.02 per gallon, plus a millage fee of $0.0035 per gallon per mile transported. These prices are only rough guidelines that may vary throughout the state depending on your manure, soil, and crop production characteristics.

If a farmer is getting value from the N, P, K than they can afford to haul their swine slurry manure about 12 miles and have it be as cost effective as commercial fertilizer. Transport distances of 5 to 20 miles are possible depending on the manure’s nutrient content. However, if only the nitrogen is of value then the hauling distance equivalent to the fertilizer value is only about 1 mile. This illustrates that moving the manure further from the farm may be justified if it provides the opportunity to better utilize all the nutrients in the manure and take advantage of the phosphorus and potassium it contains.

Similar analysis can be conducted for dairy slurry, beef manure solids, layer manure, and turkey litter. Results of all manure types are summarized in table 1. In that case of solid manure, application costs were set at $6 a ton plus an additional $2.20 for every mile the manure had to be hauled. Again, these prices are just a rough estimate and could vary considerably based on your manure, field, crop, and equipment characteristics.  If all nutrients (N, P, and K) are being valued, manures can be transported between 2 and 34 miles while still being as cost effective as commercial fertilizer; however, if only nitrogen is being valued than economically justifiable transport distances are typically only 0 to 2 miles. In general, these results suggest that solid manures could be more economically transported further distances than the liquid manures, and that finding ways to capture the value of the phosphorus and potassium can really increase how far we are able to move our manure.

So what does this mean to you? Current market conditions seem to indicate that crop prices over the next year or two might be lower than what we experienced in the past couple years. Finding ways to reduce expenditures as we try to get the crop in the field and to harvest might help in reducing our risk. Manure can play a role in this, if you have fields in need of phosphorus and others that don't strive to get your manure resources to the fields where you can take advantage of the fertility it has to offer.

Some of you may be wondering, if I can really economically justify moving manure this far, we don't we see more of it moving these kinds of distances. Well, there are really lots of reasons, but one of the most important is we generally don't have to move manure anywhere near this far to find fields that can benefit from its application, and if those fields can benefit from all those manure nutrients why not save a little money in the costs of hauling them. Another, important consideration is the amount of time it would take to apply the manure. As I'm sure most of us are aware, there are a limited number of days available in the fall and spring to get our manure application accomplished. Hauling further distances either requires us to get new, bigger equipment, to haul on more days, or to haul under some less than ideal conditions to get the job done. Thus like most things, finding the right balance so that you can take advantage of your manure resources and get the job done is critical.

As a note, in determining the value of the manure I only considered nitrogen that would be available for crop production in the first year. More information about the amount of nitrogen available in the manure can be found in the ISU publication "Using manure nutrients for crop production," which you can find at http://store.extension.iastate.edu/Product/Using-Manure-Nutrients-for-Crop-Production. 

Table 1. Break-even hauling distances for manures from different types of operations and different cases of how manure are valued. The first number represents the average manure, values within parenthesis represent how farm manure within 1 standard deviation of the average could be transported.

	Manure Type
	Swine Slurry	Dairy Slurry	Beef Solids	Layer Manure	Turkey Litter
Break-even Hauling Distance (mi) All Nutrients Value	12 (5 - 20)	8 (2 - 13)	14 (9 -20)	25 (16 - 34)	16 (13 - 19)
Break-even Hauling Distance (mi) Only Nitrogen Valued	1 (0 - 4)	0 (0)	0 (0)	1 (0 -3)	2 (1-2)
Break-even Hauling Distance (mi) P & K only (P-limited)	5 (0 - 10)	6 (2 - 11)	13 (8 - 13)	21 (13 - 28)	11 (9 - 13)