Reaching For The Moon

 Dr. Chad Lee, extension professor and grain crops agronomist for the University of Kentucky recently discussed high yield corn and its management.                                                    
 Photo by John LaRose, Jr.

Agronomist Details S-t-r-e-t-c-h Method To Grow 500 Bushel Corn

MidAmerica Farmer Grower

   High yield corn and its management claimed the attention of Dr. Chad Lee, extension professor and grain crops agronomist for the University of Kentucky recently. Lee covers corn, soybean and wheat.
   Dr. Lee recently spoke with a group of producers in Miner, MO about what he thinks is needed to get extremely high corn yields.
   “This presentation is more of a discussion about what I think we would need to get really high yields,” he explained. “It is not a discussion on economics or what may be most practical for producers in typical fields.”
   To date, two producers have reported corn yields over 500 bushels per acre. Dr. Lee said that ear count, kernels per ear and seed size would all have to be large to approach 500 bushels. He estimated the field probably has to have between 50,000 and 60,000 ears per acre, and those ears have to have around 500 to 600 kernels on them, depending upon seed size.
   “These are some phenomenal numbers, but 500 bushels per acre is a phenomenal number, also,” he said.
   Dr. Lee said that high yields also pull off very high amounts of nutrients.
   “Five hundred bushels will remove about 350 pounds of nitrogen, 200 pounds of phosphorus and 180 pounds of potassium in the grain. We cannot simply put all of these nutrients on up front. High yields demand efficient use of nutrients applied.”
   “We’re also doing some research on populations up to 60,000 plants per acre,” he reported. “That requires narrow rows. Surprisingly, most of the hybrids we have tested stand very well to the higher populations. Our yields have only approached a little over 350 bushels per acre, but we have not tested using extremely high nutrient doses. Instead, we have been more interested in trying to gain efficiency in nitrogen fertilizer uptake.” 
   Dr. Lee also discussed some things that could hurt yields.
   “If we’re going to discuss high yield we also need to talk about what hurts that yield,” he added. “Most of the time it’s the old problems that occur, such as lack of water.”
   Last year that didn’t happen, as enough or too much rain fell. While lack of water is typically the primary reason for yield loss in this part of the country, shortage of nutrients such as nitrogen, phosphorus or potassium can be problems as well.
   “Last year we had nitrogen deficiency problems, when the really good growing season combined with wet conditions early on,” he recalled. “That combination caused a shortage of nitrogen in some areas.”
   Another problem that robs corn yield every year is compaction. No one likes to talk about it and everyone is convinced that they don’t have it. But, Dr. Lee says it is among the most common problems he sees in fields.
   “Probably half of the fields that I look at when we look at yield restrictions can be traced back to compaction,” Lee reported. “It’s either sidewall compaction because somebody planted when it was too wet; or it’s subsurface compaction because machinery went across the field when it was too wet and it remained until the following year for that particular crop. So those are some of the big areas of limitation for producing high yields.
   “So for this particular scenario for both our research and the idea of producing 500 bushel corn, we’re assuming we’re talking care of all of those issues just mentioned,” he stated.
   Lee also jumped into some irrigation topics, urging farmers to make sure that water is timed out with water use demands. If 500 bushels is the goal, that’s going to demand more water for the typical crop. “The consideration then is how to do that in a way to avoid flooding out fields and drowning out plant roots,” he added.
   Many soils in this region have clays and overwatering is as big a challenge with irrigation as under-watering.
   “A couple of other big components that we don’t have as much control over would be temperature and sunlight,” Lee pointed out. “We can adjust it a little bit with irrigation. We can irrigate some to keep the canopy cooler. Sunlight is a big factor also. So you start looking at contest yields; and these really high yields almost always occur in an irrigated field where there’s dry conditions. Maybe not a full out drought, but conditions where you don’t have much cloud cover and plenty, plenty of sunlight.
   “I think if you’re making all of those (high populations and nutrient management) decisions, then you also have to protect that yield with products like fungicides and insecticides, and obviously, using a very, very aggressive weed control,” Lee added.
   While he discussed what it takes to get to this 500 bushel mark, Dr. Lee then outlined what a farmer can do in his operation to jump up 10, 15 bushels in a production cycle.
   “I think looking at the economics going forward that’s probably where the real discussion needs to take place. It’s figuring out how to get that extra five, 10 or 15 bushels per acre and how do we do it in a way that it doesn’t cost us 20 bushels to get there.”
   His take-home message for those wishing to chase after a 500-bushel yield is to have the fundamentals in place up front.
   “Timely planting into good conditions, good stand, no compaction, excellent weed control, adequate fertility, good drainage and good water application timing are the essentials,” Lee said. “You’ve got to have all of those in place in order to get good yields; once you have all those in place, then we can play with trying to really push for these ultra-high yields.” ∆
   BETTY VALLE GEGG-NAEGER: Senior Staff Writer, MidAmerica Farmer Grower
MidAmerica Farm Publications, Inc
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