Nitrogen Loss in Saturated Soils

Nitrogen Loss in Saturated Soils

Nitrogen management Nitrogen Testing

We sometime hear that lots of rain will leach our nitrogen fertilizer.  My experience is that unless the soils are very sandy, most of the nitrogen loss will be from denitrification.  In other words, the nitrate nitrogen is converted to unavailable forms. Losses will be much less on recently applied anhydrous ammonia than on fields where nitrate forms have been applied, or where early applied nitrogen has already nitrified. This article out of Mississippi puts some numbers to it.  In warm weather we can lose up to 5% a day.  Some testing might be in order when soil have dried out.  When oxygen gets back into the system, There will be some renitification.  Cultivation can encourage that, but it will not take the place of fertilizer entirely.  You models such as Climate or Yield 360 can be useful too, but I do not trust them entirely.

Nitrogen Management Webinar

Nitrogen Management Webinar

Nitrogen management

Emerson Nafziger is present a nitrogen management webinar on recent research next Thursday, March 30.  Click on the link for more info and to get registered.

Should You Split Your Nitrogen Application?

Should You Split Your Nitrogen Application?

Nitrogen management

Emerson Nafiziger discussed likely changes in removal rates for P and K at this year's crop management conference. Removal is not a good way to make fertility decisions.  You need to know what you have.

He also briefly discussed return to Nitrogen Dollars.  At least in 2016, split applications did not pay. Maximun return to N was at relatively low rates.  Check out his comments on nitrogen.  I would not change my application method because of this research, but you might want to look at the Nrate calculator to help in your rate decision.  My recommendation would be to go to the high side of the chart.

If you are applying Nitrogen right now you should be treating it as a fall application and use inhibitor.  A warm wet March would denitrify a lot of N.

Carbon Nitrogen Ratios

Carbon Nitrogen Ratios

cover crops Nitrogen management

Carbon Nitrogen Ratios were studied at University of Nebraska to see how much nitrogen is contributed to the next year's crop.  It is interesting that in looking at Carbon Nitrogen Ratios in cover crops that it appears that a high tonnage crop like cereal rye may actually contribute more nitrogen than a legume crop that fixes nitrogen from the air.  I would like to do some in season nitrogen testing to confirm this, but it looks interesting enough to pass along for consideration.

Field Activity

Field Activity

field activity Nitrogen management

Weather has been good for a while now, so there is lots of field activity.  I saw someone today using a ditcher with survey grad GPS.  I am sure I could still find corn and soybeans to harvest, but harvest is 99% complete.  Lots of people were doing tillage today.  Also lots of people applying anhydrous ammonia.  Jut a reminder that it is surprising when fall applied nitrogen is reduced to half by planting time.  I saw several people applying fall weed control measures today too.

Fall Nitrogen Management

Fall Nitrogen Management

Nitrogen management

Suppliers and farmers alike seem to like the idea of fall nitrogen application.  I saw a post yesterday that soil temperatures in Mid-Illinois are at 50 degrees making fall nitrogen application seem like  a good idea.  Keep in mind that soil temperatures can vary as much as 10 degrees depending on bare soil or covered soil.  I suggest checking each field at a 4 inch depth before applying.  The Illinois Water Survey posts temperatures daily.

Last fall November soil temperatures were favorable for applying nitrogen.  Then in December we warmed up.  by April, I started nitrogen testing and found that most people had lost half of their fall applied nitrogen.  If you insist on fall application, be sure to use nitrification inhibitors.  Split applications are a better idea than applying all at once.

No-till Farmer published a list out of Illinois of 10 Practices for cutting tile nitrate loads.  Tile is only one way that nitrogen is lost.

Running out of Nitrogen

Running out of Nitrogen

Nitrogen management Nitrogen Testing

I made a trip to Virden today to have my truck worked on,  The most interesting thing I saw is that much of our corn appears to be out of nitrogen.  Especially in wet area.  If you want a post mortem to see how you did in supplying your corn with nitrogen, you should look into doing some stalk nitrate testing.  Combining with a soil nitrogen test is a good idea to.