Top Crop Manager

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Manure maker, or manure taker?

How does your farm stack up?

November 15, 2007  By Cedric MacLeod

Often we look at manure in a too traditional mindset, the livestock industry
would likely benefit from a look at manure management in a different light.
So often in agriculture, primary producers are 'price-takers', meaning we grow
our crops and livestock, sell them at maturity or the desired market weight,
and take the going rate. This 'price-taker' approach in agriculture tends to
apply to manure production as well.

When it comes time to apply manure to crop land, producers are faced with a
watered down, low-nutrient mixture that can vary in nutrient content from one
tanker load to the next. As such, agronomists are often met with opposition
to changes in manure management, whether they are suggested to decrease manure
odour, hydrogen sulphide, ammonia or greenhouse gas emissions, or simply to
use manure nitrogen more effectively. In order to achieve these goals, we need
to start looking at manure from a different angle. We need to stop being 'manure-takers'
and instead become 'manure-makers'.

Evaluating the opportunity to add value to your manure resource will require
an analysis of your entire animal production system. For this exercise, consider
that manure is your ultimate end product, not the animals themselves. Liquid
fertilizer is a respected source of crop nutrients, so make this your target
for the manure coming out of your storage system. Strive for a nutrient rich,
low-water content liquid fertilizer. Adding value to your manure is often desired
if you are marketing the product off-farm, however, reducing manure handling
costs and the commercial fertilizer bill on your own operation will be the primary
goal for the majority of livestock producers. Therefore, we need to minimize
water, retain the nutrients produced during the animal production cycle and
get these nutrients to the field as efficiently as possible.


Using a 'systems-based' approach to manure production planning will require
you to first analyze your barn management. How much water are you using for
drinking and washing? Do you know how your water use matches up to other producers
or the industry as a whole? Things to consider for water management may include
your feeding system, as liquid feeding systems and wet/dry feeders reduce overall
animal water consumption compared to dry feed systems. Bite drinkers and water
bowls are effective in reducing drinking water wastage, and bowls can provide
significant economic savings for medicated water treatment systems. Water conserving
washing equipment, high pressure/low flow-rate nozzles will keep your pits emptier
under heavy washing loads. Water flow monitors are cheap, easy to install and
can help track and manage barn water consumption, giving you a baseline to work
from to reduce water use. These small steps should help to minimize total manure
volume without much capital investment and without sacrificing manure nutrient

Next, analyze your storage management. I recently read about a 400 foot diameter
concrete storage built in an area of the US which receives up to 10 feet of
rain a year, equalling about eight million imperial gallons of captured rainwater
each year. The farm uses irrigation equipment to apply manure liquids after
separating and settling out solids, but consider the cost of applying this rainwater
had irrigation not been an option, certainly an expensive proposition.

Consider the rainwater your operation has to apply each year by multiplying
your total annual precipitation (city averages available at by
the surface area of your manure storage. Multiply your collected rainwater volume
by what you pay per gallon to spread manure. What does rainwater cost you each

A 120 foot diameter round concrete storage in Guelph, Ontario, will collect
approximately 231,000 gallons of manure annually. Excluding this precipitation
from storage will save a producer $2310 in annual manure application costs,
assuming a $0.01 per gallon custom application rate.

Impermeable manure storage covers effectively exclude rainwater from the storage,
but can serve other benefits as well. Storage odours are virtually eliminated
with a cover system and although placing a dollar value on odour control is
difficult, in some cases, it may allow you to keep farming or reduce local opposition
to expansion plans. Besides minimizing rainwater dilution and manure hauling
costs, storage covers can offer real economic benefit by conserving ammonia
nitrogen which would otherwise be readily lost to the atmosphere from an uncovered
storage, thus adding value to your manure. Upwards of 30 to 50 percent of the
manure nitrogen produced in a barn can be lost from an uncovered manure storage.
Do the math on this!

If you currently produce manure containing 20 pounds of nitrogen per 1000 gallons,
you will need to apply 4000 gallons per acre (80 pounds N per acre) to produce
a 50 bushel per acre wheat crop. Assume a lower range of ammonia conservation
during manure storage of 33 percent, the result of installing an impermeable
storage cover. This will increase your manure nitrogen to 30 pounds per 1000
gallons. The required application rate becomes 2600 gallons per acre as opposed
to the 4000 gallons required with the less concentrated manure. Again assuming
a $0.01 per gallon application cost, you can put $14 dollars in your pocket
for every acre on which you spread manure if the nitrogen lost during storage
can be eliminated, adding value to your manure.

All calculations suggested here assume a custom application rate of one cent
per gallon. To be as accurate as possible in these calculations, you must first
know what it actually costs to spread a gallon of manure, using the farm's existing
system. To do so, make sure to include your own labour since the economic analysis
for many technologies you might consider implementing on the farm will be over-priced
if you don't.

Once you know what it costs to apply manure, consider what you can do to apply
it better within your existing cost structure, or how you can do it even less
expensively. Tanker systems are fairly cheap if you only consider the capital
cost of the tanker, as you will likely have a tractor around the farm to haul
it. But consider your time and fuel costs for empty backhauling, and potential
crop yield losses due to compaction on early wet soils. Are you applying manure
in the fall? This is a good time for trafficking fields, but not a good option
if you are trying to avoid GHG emissions, and overwinter losses will chip away
at the efficiency you are getting out of your manure nutrients. Think objectively
about dragline systems. Guys who have them, tend to love them, guys who don't
are often skeptical of their applicability, especially on small acres. Once
you know what it costs you per gallon using a tanker transport system, you will
be able to calculate how far you can go under a pipeline/dragline scenario with
reasonable capital investment.

In the event that you determine a dragline system is the best way to get your
manure to the field, you have numerous options for manure application to consider.
Drop tubes, shank type and low disturbance coulter injection units are light
on the three-point hitch and can be used in conjunction with a dragline delivery
system in early spring or throughout the fall. In-crop application to cereal
crops, such as winter wheat and barley, is another option which becomes possible
when the crop is up four to five inches and is robust enough to stand a little
traffic. Many croppers have seen the resilience of these young crops and know
that they can really come back after light trafficking, especially with a good
supply of nutrients. Research at the Prairie Agricultural Machinery Institute
has shown that in-crop application can work very effectively for maximizing
both crop yield and quality.

If you don't think so, try in-crop application on a few acres, but be fair
in your analysis. Get your neighbour or local custom applicator over for a few
strips in your field, do side-by-side comparisons in pairs, not just one strip
in a sea of fertilizer-fed wheat, and take appropriate yield samples from each
strip. Replicate them if you can, as replication will paint you a much more
accurate picture of what is happening in the field and reduce the effect of
variations in soil type. Remember, in-crop application is a way to use your
manure more effectively as a fertilizer, you might reduce your environmental
impacts, too. More importantly, you will be putting more money in your pocket
by effectively using manure nutrients.

Tanker systems do have their place and can be very effective application tools,
especially on small acreages. Small tanker units can be used to apply manure
to standing row crops such as potatoes or corn, increasing the level of manure
nutrient use efficiency in your high value crops. The key is to know which system
costs you less to apply your manure, but also consider the amount you can apply
in a day, the odours that result from applying manure using either system or
the flexibility that each system can offer.

Reducing manure odours and losses of nitrogen to ammonia during manure application
cannot be dismissed in this discussion. Granted, reducing manure odour does
little for your bottom line, but conserving nitrogen does, and when you lose
ammonia at spreading you will also be producing manure odour. The best way to
avoid both is to put manure in the ground by injecting it. A ton of research
has been completed in this area, from the size and shape of shank type openers,
to coulter injection systems, incorporation using airway pasture aeration equipment,
to the distribution manifold needed to get it to the openers evenly and accurately.
Moving to injection may present a few new challenges for your existing manure
application system, but it will keep the neighbours happy and again help to
add value to your manure.

Consider this example. If a forage stand requires 100 pounds of nitrogen per
acre and the manure to be broadcast applied contains 20 pounds of nitrogen per
1000 gallons, each acre will require 5000 gallons of manure to match the nitrogen
requirement and cost $50 per acre based on a one cent per gallon custom application.
According to the handbook, Manure Management Planning in Manitoba, broadcast
application of manure on forage land will result in a 25 to 50 percent loss
of manure nitrogen as ammonia. Assume the best case scenario of 25 percent loss,
and you will need to apply an additional 1250 gallons for a total of 6250 gallons,
costing $62.50 an acre to supply the required nitrogen.

Now, what about the value of the manure nitrogen lost as ammonia? The September
urea price in Alberta was $422.83 per ton, or $0.42 per pound of actual nitrogen.
Based on urea fertilizer equivalents, the 25 percent of manure nitrogen lost
as ammonia during broadcasting was worth $10.50 (25 pounds at $0.42 per pound).

If a producer were to move to injection, and assume that injection gives zero
ammonia loss, a benefit of $12.50 for reduced application rate and $10.50 in
conserved nitrogen will be realized. The question becomes, how far does $23
an acre go? And remember, this is based on losing 25 percent of the total manure
nitrogen. Broadcasting on a warm, dry day with a bit of a breeze is going to
push that loss much closer to 50 percent: do the math based on 50 percent loss
instead to see what economic benefit injection systems can provide.

As fertilizer, fuel and equipment prices continue to rise, while commodity
prices remain flat, the agriculture industry will be forced to continually tighten
the screws of efficiency. It is easy for agronomists to write down a few ideas
and think that farmers will run to the shop and build an injection unit for
the tanker, or call the local manure storage cover provider. That doesn't always
happen because only you can really determine the best management practice changes
for your farm.

The food-for-thought ideas presented here for adding value to your manure,
are part one of a two-part series. Part two will be featured in the spring edition
of Top Crop Manager, to tell the story of a few producers who stepped
out of the box to find value in their manure. Until then, think about what your
operation needs to do to become a 'manure-maker' as opposed to a 'manure-taker',
think about how you can add value to your manure.

Cedric MacLeod is Greenhouse Gas Mitigation program co-ordinator
at the Canadian Pork Council.


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