The Crusting Conundrum!

The Crusting Conundrum from Central Valley Ag on Vimeo.

by Keith Byerly

by Keith Byerly

As this growing season continues to progress, we continue to see the effects of a challenging spring on a daily basis. Some things are obvious like weed control, plant height, stand consistency and so on. Others are harder to identify. Things like rooting problems, the movement of nutrients in the soil, and things of that nature. One big thing I saw this spring that we only talk about for a very brief time though is crusting. Those of you that had to replant some soybeans, or run the pivot around to get the crop out of the ground are aware of the challenges that crusting ran us through this spring. But the challenges from crusting are far from over for the season.

If I put on my Agronomist hat here for a moment, soil crusting is related to soil texture, and organic matter. The finer the texture, the more that the soil aggregates break down into particles with rain. As the soil particles wash and move, they settle into pores, clogging them, and it seals off our soil. Crusting is a result of our management activities; specifically when we leave soil bare. So as you think about the value of removing residue, this is a hidden cost on the backside because we are leaving the surface susceptible to impact from rain droplets. Excessive tillage tends to break up soil structure and bury plant reside. These can be good things from a seedbed and soil temperature side but can lead to problems with the right conditions.

So as I said, we think of this as an issue only when it comes to getting the crop out of the ground. But that crust is an indication of poor infiltration and reduced air travel through the soil. Additionally, a crusted soil tends to reflect more sunlight, leading to cooler soil temperatures which can affect nutrient uptake. And of course, we are more subject to wind and water erosion when a soil is crusted. All of these are obviously very bad things. So what can we do about them?

Of course, a lot of this comes back to the management practices. But we are in the middle of a growing season. We don’t have an opportunity to change that for this year. So what can we manage?

Again, it comes back to water infiltration. My take home for you today is, that if you battled crusting to get your crop out of the ground this year, then irrigation management is essential for the remainder of this growing season. As your water infiltration rate is cut down, you will have to make smaller applications of water to reduce runoff in your field and do it more frequently. And this is where technology comes into play. A moisture probe like we provide with AquaSystems will help us understand how much of what we apply makes it into the soil. Every year we see a difference between the rain gauge and the increase soil moisture. This is due to infiltration rate. The closer we can match irrigation rate per hour to infiltration rate per hour, the better it will be for our irrigation expense. We certainly don’t want to be in a position where we are applying 0.75” of water, and watching our ditches run knowing that the soil is dry and the crop is showing stress.

So have a conversation with your ACS Regional Specialist about what we see with AquaSystems probes. We can’t develop a plan to manage what we can’t measure. Once we have an idea of what is going on, then we can analyze how effective variable rate irrigation might be for your field. As your soil type differs so does your infiltration rate. Managing the water holding capacity, the infiltration rate, and the yield goals across those areas is a tricky proposition. But, if we have a good plan in place, then we have a fighting chance.