I often get asked the question what does the future of the manure industry look like. I typically give a little thought and then reply, a lot like it does now, we’ll continue to try to get better at finding ways to more quickly and accurately apply the manure nutrients so we can better capture the fertilizer value. I say this because I mean it; manure can be a great fertilizer resource on a farm and when we think about, livestock production is a critical component of sustainability as the majority of nitrogen, phosphorus, and potassium we feed ends up in the manure and needs to be recycled.
Today I’m going to stop and consider this number a little for you – we are going to focus on liquid manure in Iowa. There is somewhere around 10 billion gallons of manure produced annually (give or take a billion here or there depending on rainfall and the accuracy of my animal populations, the production systems I assume farmers are using, and general variation). It’s a bit hard to fathom this number but I’m going to try a couple ways. The first is if we think of a 40-acre field the manure would be 767 feet tall, or just a little more than the 801 Grand (previously The Principal Building which as far as I can tell is the tallest building in Iowa. Of course Iowa really has around million acres so if we tried to put or manure on all of them each acre would only get around 500 gallons (or you know a little less than 0.02”).
As interesting as that is, today I wanted to take a look at slightly different topic, manure application logistics. So we know we are working with approximately 10-billion gallons of manure and if we look in the fall we have approximately 75-days between October and mid-December and then another 30 days of potential application in the spring. So we are looking at somewhere around 105 application days in a given year (give or take depending on the exact day we start applying and the number of days unsuitable due to soil and weather conditions). That means to get all our manure applied we need to apply somewhere in the neighborhood of 100-million gallons per day!
So what does the typical logistics of application look like?
If we think about a drag-line system, when it’s flowing we are probably in the neighborhood of 1500 gpm for a flow rate; however, there is some setup time involved as we move to new fields. Just for fun let’s figure that we are somewhere around 50% efficient with this system, that is it is running half the time and being reset the other half of the time. If this is true we’d average around 750 gpm or about 45,000 gallons per hour. Assuming 12-hours days (some companies run longer but I need some time to clean and move from farm to farm) we’d need about 18,500 days to finish all the manure in Iowa! Luckily there are lots of companies out there to help with this big task.
Figure 1. Manure application with low-disturbance injectors into covercrop.
Similarly, if a manure tanker is used (let’s just say it is a 7300-gallon tank and we get it 95% full with each load). Let’s say we are hauling three loads an hour then every hour we are moving 20,000 gallons. To finish hauling all the manure in Iowa in those 105-days we’d need somewhere around 400 manure spreaders going not stop 12 hours a day.
Luckily Iowa farmers and commercial manure applicators have recognized this challenge and continuously are purchasing new and better equipment to help ensure they are moving manure from farm to field as cost effectively and responsibly as possible.