Greg Endres: I’m Greg Endres, NDSU Extension Service Agronomist based at the Carrington Research Extension Center.
I’d like to highlight a corn study where examine three different factors. The first is response of corn to tilling systems. The second is response of corn to starter fertilizer placement. The third is the response to row spacing.
The first factor in the study was comparison of three tilling systems. The first was conventional till with amount of small grain residue was less than thirty percent. Often times ten percent or less. The second tilling system was direct seeded where corn is planted directly into the standing small grain stubble. The third system was strip till where in the fall strips were made and then the following spring corn was planted into the those strips as is pictured.
This graph shows the average yield across the five set years that the study was conducted comparing the tillage systems. The work was conducted in 2007 through 2010 and again this past season in 2012. As you can see, average across the years, a very similar response of the corn to all three of the tillage systems.
Next I’d like to talk about the impact of placement of starter fertilizer for corn. In general NDSU’s recommendations are to have a goal of having high testing soil for both phosphorous and potassium. We recommend applying a starter as a band within two inches of the seed to provide an opportunity for the plant to get an early season growth. Our standard recommendation would be to apply the fertilizer within two inches such as a two by two inch span and we would expect the corn response to be greater versus infertile application of the starter and have a greater impact versus not using a starter fertilizer at all. Corn responds to zinc and if your soil test is less than one part per million, we would recommend applying some starter zinc.
In the study we had four basic fertilizer placement methods. They included untreated check and then fal deep ended ten thirty four o, placed at the time we fall strip tilled. Then another treatment was placing ten thirty four o infertile as well as a two by zero band which would be two inches horizontally from where the seed was placed. Also note the phosphorus soil test as listed on the bottom of the graph and also the rate of ten thirty four o which ranged anywhere from five to twelve gallons per acre based on the soil test and fertilizer application methods. So average across the four site years which include 2008 to 2010 and 2012 we did see a trend for a yield response with the two by zero band and the fall deep band as compared to the untreated check. The infertile application was actually slightly less than untreated check and probably due to stand loss because of the fertilizer placement directly with the seed.
The third factor in this corn study was the response of corn to twenty two inch rows versus thirty inch rows. The study started just this past season in 2012 so only have one set year of data. The data is encouraging showing that the narrow rows, the twenty two inch did provide a five percent yield increase compared to the standard thirty inch row spacing.
In summary the corn response to tillage systems was very similar across the five site years. This may have been due to a well drained loam soil, timely planting of corn but not planting early, and also planting into residue that was modest. Small grain residue for example as compared to corn residue.
The starter fertilizer placement averaged across four site years, we see a trend toward having better yield with the two by zero band and that being similar to the fall deep band and both greater than the infertile starter fertilizer application.
Finally, with very limited data just one set year, we have seen a yield advantage with having narrower rows, in this case twenty two inch versus the standard thirty inch rows. The advantage so far was about five percent. The study will be continued into 2013 where we will continue to examine the response of corn to the starter fertilizer placement as well as the row spacing.