Thursday, May 05, 2011
How Important Is Planting Date, Really?
When did your Dad plant corn, or tell you that it was time to plant corn? While that date may be plowed across our mental field, corn planting dates have to be adjusted about every year. Yes, early planting may lead to higher yields, but will not guarantee them. Essentially, the planting date is only one factor that influences yields, so if you are fretting about missing the target, there are still other targets to fire at.
If you are losing sleep about not being finished (or started) planting corn, get a grip, adjust your outlook on life, and remember that your Dad also told you that you can’t do anything about the weather. But with the wet spring that has washed out the April planting schedule, let’s see what the other factors are that may determine your yield. Purdue corn production specialist Bob Nielsen has a collection of “yield influencing factors” (YIF.)
Just so you would not have to do it, Nielsen analyzed the USDA’s Crop Progress reports for the past 20 years and found “there is NOT a strong relationship between planting date and absolute yield on a statewide basis for Indiana.” Sure he was looking at Indiana, but the same can be said for other states. And he adds that departures from annual trend yields are not strongly related to corn planting progress. Do you feel a little better now?
Nielsen says planting date is only one of those YIF’s, but is willing to address the issue of why he and all of his Cornbelt colleagues preach the importance of timely planting, yet only 12% of the variability in yields can be attributed to planting date. While many farmers look at the May calendar and start deducting yield, Nielsen says the yield “potential” does decline after May 1, however, he says the yield potential declines because of a number of other factors, including, “a shorter growing season, insect & disease pressure, and moisture stress during pollination.”
Nielsen says all of the yield influencing factors work together to determine a maximum possible yield. It the combination is a 200 bushel yield, then the planting delay might reduce it to 190 bushels. However, if the combination is a 160 bushel yield, then the planting delay would reduce it to 150 bushels. That’s why he says early planted corn one year may yield 190 bushels and the next year the same planting schedule may yield 150 bushels.
The Purdue agronomist wants you to think back to the 1997 crop that was planted early, but yielded 8% below the trend line. And he says think back to the 2009 crop that was planted late, but yielded 8% above the trend line. Nielsen says the difference is the other yield influencing factors, not the planting date.
If you don’t believe him, and are “mudding in” the corn crop, he says that is probably an unwise decision. You have the equipment to catch up when the weather and soil become favorable for planting. And based on the 2010 crop, 50% of the corn was planted over a period of 21 days, and a state can get 45% to 50% of its corn planted in a given week if there are good working conditions.
Summary:
The planting date for corn is important, but not as important as a collection of factors that influence yield. Other factors include disease and insect pressure, moisture stress during pollination, and the length of the growing season. Corn can be planted early but yield below the trend line and corn can be planted late and yield above the trend line. And proper soil conditions at planting can be a significant factor, so don’t plant before the soil is ready.
Posted by Stu Ellis on 05/05 at 12:00 AM | Permalink
Comments
Posted by: Jib at May 6, 2011 12:12AM
Stumbling” on Analog Years
The commodities market, more than any other place, uses analog years to try to correlate outcomes between years/events. They can give a hint of possible events (as pointed out in the blog). The challenge is no two years match perfectly. Their value is always in question (as also pointed out in the blog). So with that as my crumbly foundation, I continue.
The years 1984, 1993, 1995 and 2008 had early US planting progress similar to this spring’s. Two years, 1984 and 2008, have yields above trend line. The other two years were below trend line. The level of estimated rationing, in the 2011-12 marketing year, that might be required is listed as a percentage of projected use, in the chart below:
Million Planted Acres
Year 93 92 90
1984 0% 0% 1%
2008 0% 0% 2%
Mid 4% 5% 7%
Ave 6% 7% 9%
1995 10% 11% 13%
1993 18% 18% 20%
The two higher yield years would have tight ending stocks and a small level of rationing when 90 million acres of corn were planted. The two lower yield years would require a substantial reduction in use regardless of planted acres. To give a feel for the level of rationing that might be required; a yield year like 1993 with planted corn of 90 million acres is estimated to require a reduction of 20% of use. That would be a little more than half of the corn fed all livestock.
There is a challenge in rationing corn in the livestock sector. The production of meat and poultry can be viewed, somewhat like, placing animals on a Ferris wheel. They go on at breeding or birth, depending on your point of view, and come off after one trip around at slaughter. They are hard to remove prior to completing the trip. Each industry has a different amount of time required to make the trip. Hogs may require at least 5 month (a lot long if from the time from breeding is used and longer yet if breeding stock is required to be raised) while broilers are around 6 weeks. If course grain production comes in at a level that requires rationing in the livestock sector, prices will need to be up for new crop by mid-July or early August to keep the Ferris wheel from being fully loaded on September 1, 2011, if this sector is to do most of the rationing. In a rationing environment the more months of full use we have, the larger the reduction that is required at the end.
For those that want to move past analog years and look at all yield possibilities, corn yields are expected to be above 1984 about 30% of the time, below 1993 20% of the time and between the 1984 and 1993 50% of the time. When all years/yields are included it looks like rationing would be needed 70% of the time while 30% of the time yield should be high enough to meet demand.
The analog approach with Zoodoo (a process that finds answers no matter how wrong) indicates a year like 1984 would provide price support in the $5.73-$6.14 per bushel area for corn on the board at harvest. The 50%/50% chance of rationing, with the analog approach, has fall prices on the board north of $8.80.
Speaking of analog years, a similar situation as new crop corn this year occurred in 2008. The balance sheet, that year, was balanced with a 190 million bushel increase in beginning stocks, a 360 million bushel increase in production and a decrease of 450 million bushel in total use. A billion bushel swing occurred when comparing WASDE’s June 2008 balance sheet with current data for the 2008-09 corn marketing year. So many surprises could still await us.
The analogs seem to be saying; “Corn grower will either have a good yield or a “wild” price.” The livestock feeders may view them as a chance to evaluate their input risk.
Jib aka Gibberish