Variable Rate Decisions

Variable Rate Decisions from Central Valley Ag on Vimeo.

by Keith Byerly

by Keith Byerly

Last week, I challenged you to take a serious look at your fields and face the variability head on when it comes to things like soil fertility. As I reflected on my blog, I knew there was more that I wanted to say about Fertility and Variable Rate Application. So this week, I am going to dive right back into it…

When it comes to fertility, I think a lot of people have an all or nothing attitude. In fact, there are three levels we need to talk about; Build, Sufficiency, or Depletion.

BUILD is very simple to define, whenever we apply for fertilizer than we remove, we are in a build program. More often than not, a build is a plan to correct a deficiency, but sometimes it comes from lower than expected yields.

A SUFFICIENCY program is trickier. We aim to apply a rate that is very close to our crop removal, but as our yield varies, so does the appropriate rate for a sufficiency applications. Those years when we fertilize for 225, and we grow 245, we no longer applied a sufficiency application but had a DEPLETION. And of course, the depletion is any time we removed more nutrients than we apply.

And within those three rate ranges of application comes one more variability in our field, and that is the variability in soil nutrient recommendation. Ultimately, this is what started the conversation last week. High soil fertility levels can sometimes be found where the worst crops are grown, and the lowest fertility levels where the highest yields are collected. That’s why we need to look at soil tests along with yield maps and yield goals to start to put the story together in its entirety. That is why the process starts now. Managing your field, its variability, and ultimately, VR applications start now, as soon as crops come out of the field.

Our team of ACS Regional Managers, and the FSA’s all understand that there is no one size fits all. We need to communicate with you to determine yield goals, identify the most problematic spots, and determine appropriate application rates. Remember how I was talking earlier about Build, Sufficiency, and Depletion. I will argue with you that it is far more important now to make sure our fertility plan is the best it can possibly be now vs. when corn was $7.00. Of course, a fertility plan needs to work within the constraints of your budget. We want maximum ROI for each dollar you spend on fertilizer, and that is why we are improving our sampling programs. That’s what we are aiming to do, because in some areas of your field a planned build may still be called for, while in other areas, we may actually be mining nutrients.

I really want you to remember one thing when your FSA or ACS Manger is working with you back and forth on appropriate fertility rates. Your long term success is the key to our long-term success. If we are pushing you to apply more fertilizer than you are comfortable with from a budget standpoint, stop the conversation and let’s get the agronomics on the table. Fertility is a constant ebb and flow, and your fertility rates need to adjust yearly to meet those needs.

The thing is, we need a plan everybody understands and is committed to. Without a plan, we flail around, but if we’re on the same page, we move with more purpose and speed. As you complete harvest on your fields, help us by putting things in motion and let us get started with the plan by letting your FSA know a field is done and ready for sampling.