This week we are finishing our third wave of fungicide application to corn fields. The last few years, tar spot has really become an issue in our area. In fact, there is a micro-climate just to the northwest of us where tar spot is absolutely devastating if not treated multiple times.

We are planning two applications at this point in time. Hopefully we can get three weeks of protection out of this V10-V12 application. Then we will go back in at R1 and do it again.

We may choose a longer-lasting product on irrigated fields, or we may opt for a fertigation trip later based on disease pressure. We just haven’t made that decision yet. Total cost is about the same either way. Irrigation is great to have when you need it, but one of the side effects is that you can add to disease pressure because you are keeping the field at a higher moisture level.

More nitrogen

We have also been applying some pre-tassel nitrogen to the irrigated fields through irrigation. We are wanting to keep the plant very happy as we go into pollination and grain fill.

This year we have shifted toward using ATS (ammonium thiosulfate) or AMS (ammonium sulfate). We need the sulfur anyway, and some consultants we work with have told us corn prefers the ammonium form of nitrogen and can use it immediately. There is some debate on whether the form of nitrogen applied to corn matters. Maybe we will find some answers at harvest. I am not the plant expert I should be.

Bring on the rain

We caught a little bit of rain late last week. Hopefully it will push the y-drop nitrogen into the root zone on dryland fields. Tissue tests have been running light on nitrogen the last few weeks. If they don’t improve, we may have to consider foliar nitrogen with our next fungicide application. But, if we catch a few timely rains, the nitrogen that is there should be enough. If we don’t catch rain, I’m not sure it will really matter.

We have been dry, but just catching enough rain to keep crops going. I can see on my soil moisture probes that we are depleting subsoil moisture even in irrigated fields. That is not good when we’re headed toward grain fill, but that also tells me there is a good root structure underneath those plants.