Monday, October 20, 2014

Precision Farming and Manure

Recently, I have been hearing a few buzzwords (precision agriculture, big data, and even precision conservation) that really got me thinking about what these ideas mean in terms of our manure management. Often times when we hear the word precision agriculture it brings to mind the newest equipment being controlled precisely to drop a seed exactly where we want it. While I think this is an important part of precision agriculture, to me at its heart it is all about providing site-specific management practices within our fields to improve our crop production and lessen impact on the environment. This means we need innovative ways to understand our agriculture decision and then methods to take this information, determine an optimum way to move forward, and then implement the management practice we determined would work the best. I break it down into three important steps – measurement, decision-making, and implementation.

The first two steps, measurement and decision-making aren't always what gets the most glamorous, but they are probably the two most critical steps, and this is really what the new buzz term “BIG DATA” is. In agriculture, there are all kinds of information available at our fingertips: market prices, weather forecasts, soil types, planting population maps, past yield maps, or maybe even aerial photos of what are crops currently look like. This means there are many pieces that we need to take into account as we try to make a decision about our best course of action on what we should do to “get the most from our field.” In many cases, we rely on our experiences in similar situations to make our decision based on our current condition.


 I like to think of this in terms of sports, practice and then do. I don’t know if any of you are basketball fans, but with the season starting up again I thought this would be the perfect chance to mention it. You may recall last years’ NBA finals pitted the Lebron led Heat against the Spurs, but here I’m going to focus on the a mall moment earlier in the Spurs season. Spurs down by 2, 9.5 seconds left, Spurs ball… Park takes the ball and using a Duncan screen attacks from the left wing for a layup, but at the last second sends a pass to Leonard on the weakside for a corner three, which of course he makes for the win. Why did this happen? Well, of course practice and experience, but at a more data driven level (good old sabermetrics) we know corner threes are the best shot in basketball (most points per attempt, but corner threes are typically assisted) so the Spurs drew up a play to give them the motion to get one of their better shooters into this position. Did it mean it would work? Of course not, but it gave them the best chance to succeed. Precision agriculture is the same thing, it might not always work like we wanted, but it’s the idea of putting us in the best chance to succeed.

So how do these precision concepts fit with the world’s oldest fertilizer, manure? Well, in the long run it may mean trying to implement more site-specific manure management practices, but in the short run it means making sure we are getting the right data to inform us and then using this data to make decisions. When I think of this “precision ag” concept in terms of manure nutrient management, there are really four basic steps/or principles. 1. Measure the nutrient content, 2. determine the application rates needed, 3. control the rate applied, and 4. produce a record of where and when that application occurred.


Many factors cause variations in the nutrient concentration of manure, including diet, housing type, manure storage type, environmental conditions, management techniques, and treatment practices. Given the variability in composition, manure sampling and subsequent testing for nutrient composition is a critical component of proper management. For example, while “book values” are reasonable averages, they are just that, averages, they don’t represent your farm. It’s not uncommon for one farm’s manure to vary by 50% or more different from that average manure. For example if you asked me what I thought was the typical nutrient content of swine manure I’d probably say something like 50 lbs of N/1000 gallons, but I look at sample results all the time that have 60, 70, or even 75 lbs of N per thousand gallons. This means we can get a big financial advantage if we can manage to make the best use of these manure nutrients.

Next time I’ll provide you will some more details on how to use the results of manure sampling and testing and provide some insight into the economic value this decision making might have on your farm, but for right now I just wanted to make you aware of some resources on how to collect a good manure sample. The resources is “How to Sample Manure for Nutrient Analysis” and you can find it at http://store.extension.iastate.edu/Product/How-to-Sample-Manure-for-Nutrient-Analysis