Home News Agriculture Extension Update by Gary Zoubeck

Extension Update by Gary Zoubeck [March 12, 2015]


Coming Events

March 12, Chemigation Training, 1:00 p.m., 4-H Building, York

March 12, Pesticide Applicator Certification Training, 6:30 p.m., 4-H Building, York

York County Corn Grower Varity Comparison Plot Planned

Has your seed company entered the York County plot?  If not, how about encouraging them to support the York County Corn Growers and our industry by participating.  The plot will again in 2015, be on the Ray and Ron Makovicka farm located East of York.  All interested seed corn companies are invited to participate.  For entry information go to: http://york.unl.edu/crops-future and click on the appropriate link.

Entries are due this next week.  Give me a call at 402-362-5508 or email me at gary.zoubek@unl.edu for more information.  With days like today we’re all thinking spring.

Best Management Practices (BMPs)

I just got back from traveling in the SW United States and saw some beautiful and some not beautiful country.  I understand that last week was a good one to be gone temperature wise, but I experienced a wide range of temperatures in the one state I was in.  Temps varied from 18° F to 82° F while I was there.

This morning I made a presentation in Shickley for Daryl Anderson and the Little Blue NRD on Best Management Practices or BMPs for nitrogen and water management.  The reason I’m bring up traveling to other parts of the country is that BMPs vary depending upon what crops you are growing and your particular situation.  All BMPs will not work on all farms.

You cannot talk about nitrogen management without talking about water management.  In your area they go hand in hand.  So where do you start?  I believe that the 4 Rs is a good starting point.  The Right nitrogen source, the right rate, the right timing and finally the right placement.

So with it beginning to look like spring I wanted to share some of the topics we visited about.  As you plan your fertilizer program for the coming year I hope you’ll collect composite soil sample 0’8”, 8-24” and finally 24-36”.  Collect several at each depth and keep them separate to find out the amount of carry over N.

Our UNL recommendations are based on the following formula.  35 + (1.2 x yield goal) – (0.14 x Yield Goal x % Organic Matter) – (8 x average residual soil nitrate ppm) – (other credits for legume, manure or nitrates in irrigation water).  In addition, our formula also has adjustments for time of application as well as the corn and nitrogen price ratio.  If you’d like to go to our CropWatch website you can down load the excel spreadsheet at: http://cropwatch.unl.edu/soils or you can do it manually with our EC Fertilizer Suggestion for Corn: http://www.ianrpubs.unl.edu/live/ec117/build/ec117.pdf.

So what is the proper yield goal?  I’ve mentioned it before, but for the past several years our trend line for irrigated corn in the York area is an annual increase of 3.27 bushels/year for irrigated corn.  For your yield goal we suggest taking the last 5 years yields, average them and increase by 5%.  If you have an unusually low or high yield drop it out.

Look at that adjustment for Organic Matter (OM)!  The more OM you have the less nitrogen you are going to need to apply.  On average for each one percent of OM you can reduce your nitrogen application by about 30 pounds and no yield loss.  So, anything you do to maintain or increase OM is valuable.  Kind of does not seem fair?  You can apply less and in most cases get better yields.

Once you get your soil samples back for each 1 ppm or residual nitrogen you have to the three foot depth you can reduce you nitrogen needs by 8 pounds.  So if you have an average of 5 ppm in you three foot profile you would reduce you nitrogen needs by 40 pounds per acre.

What was your previous crop?  If it was soybeans and they yield 45 or more, we would credit them for 45 pounds of nitrogen.  Did you apply manure or how much nitrogen does your irrigation water have?  For estimating credits for irrigation water, for each ppm of nitrate nitrogen in your water, we can credit 2.72 pounds of water per foot of water.  Hopefully most years we won’t need 12” of irrigation so for a well testing 15 ppm and we’re planning to apply 6” of water we could credit 20 pounds of nitrogen.

So the math looks like this: 35 + (1.2 x 240) – (.14 x 240 x 3) – 40 – 45 – 20

35 + 288 – 100 – 40 – 45 -20

323 – 205


So for this example our starting point would be about 118 pound of nitrogen needed on this field with 3% organic matter following soybeans with some carryover nitrogen.  You don’t know that unless you soil test.  Soybeans do a good job of scavenging nitrogen so your field might have less carry over.  It’s also important to test your irrigation well.  Most NRD will test if for you, so be sure to check with them.

When you apply the nitrogen is another critical point, ideally as close to utilization as possible will get you the most for your dollar and reduce the chances of leeching.  Since soils, organic matter and nitrate nitrogen all have negative charges, the nitrate nitrogen is very mobile and can move with excess water that move thru the profile. If possible split your nitrogen applications to get the most efficient utilization.  You can apply 20-40 pounds of nitrogen with the center pivot and very little water even during wet periods.

I asked the question what better applying 75% of crop Evapotranspiration (ET) or 125% of ET?  I research done by Suat Irmak in 2006 near Clay Center the 75% plots yielded a little over 242 bu./acre while the 125% plots yielded 238 bu./acre.  You paid for the extra water and got a yield penalty at the same time.  Roots need some oxygen, so you don’t want to over irrigate and move the nitrogen.

The most common definition of irrigation scheduling is simply the determination of when and how much water to apply.  How about a new 21st century definition that can be stated as “The process of delaying any unnecessary irrigation with the hope that the cropping season ends before the next irrigation is needed.”  Hopefully your using tools like ETgages and Watermark sensors to help with your irrigation decisions.  More can be found at: http://water.unl.edu/nawmn.  I’d be glad to visit with you about these tools.

The same can be said about nitrogen application rates.  The first few pound of applied nitrogen give us the biggest bang for the buck.  As we get above that we’ll get less of a return or in many cases a negative return.  Good BMPs are good for the bottom line as well as the environment, climate change and greenhouse gasses.

Finally what’s the cost of getting it wrong?  Extra water costs to apply it; extra water moves nitrate nitrogen by about 5-10 lbs/inch of water moving thru the profile.  Extra nitrogen is not needed when it does not move, but extra nitrogen is needed when water moves it below the crops root zone.

We’ve got lots of technology available but it’s important to stress the we need the man or women in management to go along with the technology and both can only be optimized in the presence of the other.

I hope you’ll check out all our resources at CropWatch and or Water webpages.  Those addresses are: http://cropwatch.unl.edu/ and http://water.unl.edu/.  Feel free to contact me at 402-362-5508 or email me at gary.zoubek@unl.edu.

Nebraska Farm Real Estate Values & Rental Values

Nebraska Farm Real Estate Values slipped 3% this past and cash lease rental rates followed a similar pattern with rents increasing on hay and grazing lands.  These trends follow our trends in commodity prices.  This information along with the latest release of National Ag Statistics NASS yields are posted on CropWatch.  You’ll want to check it out at: http://cropwatch.unl.edu.

Reminder Chemigation and PSEP Certification

If you’re intending to get certified for chemigation or private application training I’m doing them both this Thursday at the 4-H Building here in York.  Chemigation at 1:00 p.m. and pesticide safety education that evening at 6:30 p.m.



Powered by Facebook Comments