04-18-2013 02:11 PM
Anybody done some historical comparisons regarding final national corn yields compared to average planting dates? While we're not "late" yet, it's not "normal" in this area to have essentially nothing planted at this point. It's good to have the moisture back in the ground, yet if it stops raining right now, it would be a week before we could get into the field. Forecast has more rain coming this weekend and early next week, so push that out another week and we're looking at around May 1 to get started at this point. That's essentially a month behind what we've been seeing in this area the past several years.
04-18-2013 02:40 PM
southern Mn...6inches of snow last week, another 3-4 inches today of blowing drifting white stuff...schools are let out at noon.
I will go out on a limb and say that there won't be any corn planted here in the frozen ground for a little while.
04-18-2013 05:12 PM
04-18-2013 10:38 PM
how you been?
think after May 10-15 is when you start knocking off a few bu/day......then after Jun 1-5 potential yield loss starts to go parabolic------------on average over US.
04-19-2013 10:08 AM
I'm familiar with what the experts say on yield vs planting dates. Personally, don't like planting too much after May 15, yet latest I've actually finished was June 16th -- in 1995, got most of corn planted 1st half of April, but actually finished on June 16. 1995 was very wet here last half of April and thru much of May, then basically quit raining in early June and dry rest of growing season -- had some soybeans that never got a rain that year.
Was just curious if anyone actually put any numbers together -- Like ending national avg corn yield comparison to avg national date of 50% planted -- Just to see if there was anything that might be informative. Don't know where/how to find that historical planting progress information.
04-19-2013 10:32 AM
How were the yields in '95 on your corn planted June 16???
might be a good micro comparison model, then look for avg GDD for different latitudes ( possible photosynthesis decreases in a log fashion (it's like a bell curve) this is because of Earth's elliptical path around sun ----reason you get less summer in MN than Missou....
Then maybe i can figure out a formula for it.
04-19-2013 11:08 AM
More interested in national-level avg information - that's what impacts supplies/prices.
Had to dig a little to locate my own 1995 information -- that was a long time ago. 1995 avg corn yield 109, compared to APH 129 at the time. Field planted June 16 made 98 @ 19% moisture, harvested 2nd week in November. 1995 avg soybean yield 39, compared to APH 48 at the time. All soybeans were planted after finishing corn on June 16. 1995 avg wheat yield 33, compared to APH 54 at the time, and I remember the quality of the wheat was poor (I put it in the bin and used it in cattle feed -- had crop insurance, but never turned in a claim). So, in 1995, all my yields were off my averages by quite a bit.
04-19-2013 11:58 AM
understood about US avg.........so if you can figure avg GDD for say 4 different latitudes starting where you are WC Mo, correct?.AND move north......amount of daylight decreases logarithymically as you move north (GDD'S)....might be able to derive a math formula for it.
SO the more north one plants, the more effected the yield is per SAME LATE PLANTING DATE.
ie. 6/16 planted corn in Mo. has MORE yield potential than 6/16 planted corn in Morris, Mn. make sense?
for 1995 US APH = 129. Mo corn is on avg gonna be LESS affected by late plant than Mn. If avg plant date for entire US was 6/16 in 1995 - be easy to figure. so find a ballpark avg plant date for that yr.
if summer was ok growing weather in 1995, you could say the late planting caused 20/129 = 15.5% yield reduction.
here's a graph from Univ. of Mn - Extension--southern Mn.--potential yield loss is almost 25% by 6/1 and 45% loss by mid-June.
Figure 1. Response of corn grain yield to planting date at Lamberton, MN from 1988 to 2003. Data from Bruce Potter and Steve Quiring.