Can't plant? Don't worry yet
If you're pacing a trough in your shop or office floor waiting for things to warm up and dry out, all the while worrying about how much corn yield potential you're losing by not getting your crop planted in the timeframe you had hoped, don't let it get you too far down.
You may have missed the "ideal window" for planting, but that doesn't mean you're any worse off than if your seed was sitting in the soil and not in the bag right now, according to Purdue University Extension agronomist Bob Nielsen.
The best estimates show you lose about 1 bushel/acre/day in yield after about May 1, and that number doubles once you reach the end of the month. "Yield potential goes down with delayed planting because of a number of factors, including a shorter growing season, insect & disease pressure, and moisture stress during pollination," Nielsen says.
That's the bad news. The good news is you're not playing yourself out of a good crop just because you're late getting the seed in the ground. Planting date is just one of many "yield influencing factors" (YIF) that determine what kind of yields you'll pull in from the field this fall. So, even if you plant later than what's considered ideal for your area, you could still net good yields.
"What is important to understand is that yield loss to delayed planting is relative to the maximum yield possible in a given year. In other words, if all the other YIFs work together to determine that the maximum possible yield this year is 200 bushels/acre, then the consequence of a 10-day planting delay beyond May 1 (at 1 bushel/acre/day) would be a yield potential of 190 bushels/acre (i.e., 200 bushels/acre potential minus 10 bushels/acre due to delayed planting)," Nielsen says. "However, if all the other YIFs work together to determine that the maximum possible yield this year is only 160 bushels/acre, then the consequence of a 10-day planting delay beyond May 1 (at 1 bushel/acre/day) would be a yield potential of 150 bushels/acre."
Nielsen points to yield data for Indiana in 1997 and 2009. The vast majority of the 1997 crop was planted by May 15, yet in general, yields were more than 8% below trend. In 2009, only about a fifth of the crop was in the ground by mid-May, but it ended up 8% above trend yield. "Why? Important differences in YIFs between the years other than simply planting date," he says.
Even though you may be feeling compelled to get your crop planted at all costs right now as soon as you can, you're in the long run doing more damage to yield potential by pushing it now than you are if you wait until conditions improve.
"Let's not succumb quite yet to fearmongering triggered by the prospects of a delayed start to corn planting in 2011. 'Mudding in' a crop early to avoid planting late will almost always end up being an unwise decision. While important, planting date is only one of many yield-influencing factors for corn," Nielsen says. "Another reason that it is probably too early to fearmonger about the anticipated late start to planting is that growers have the machinery capacity to 'catch up' quickly once the weather and soil conditions become favorable for planting."