Just like every spring, 2012 provided its own set of challenges to getting a crop planted and established here in southern Iowa. Like much of the Midwest, we had a very mild winter with little precipitation. This was welcomed by my cow-calf neighbors as they didn’t have to fight the cold and mud during spring calving season. It also set our minds on putting crops in sooner than we usually do.
Some corn was planted around April 10, the first day sanctioned by crop insurance, but not a great amount. The first big wave of planting occurred two weeks after that, between April 23 and 27. A rain event or two had occurred in between, but we dried out pretty well for the week. I completed my corn planting (some corn on corn) and even started planting soybeans that week.
Right after this planting period, however, we were hit with a period of cold and wet weather. About 3 inches of rain accumulated, some of it running off. Because of this, fusarium and other seedling diseases took hold on the corn trying to emerge.
By the next window of opportunity it became apparent that many acres needed to be replanted. As you may have seen or read about, if the corn did manage to emerge, some failed to set roots, working only off the kernel for energy. In my case, replanting was necessary for both corn and soybeans. I set out to do this around May 15. Some neighbors had hundreds, if not thousands, of acres of poorly emerged corn to field-cultivate over and try again.
Many acres were replanted
At this time we welcomed the warm and dry southwest winds to vaccinate against a repeat of drowned crops. Corn and soybeans were planted in record time during this period. But it soon became apparent that topsoil moisture was running out.
I had set my planter depth shallower because I didn’t want the beans and replanted corn to be sitting in cold, wet soil again, but perhaps that wasn’t the best decision. I found later that each day later I planted, the slower the emergence was on the soybeans due to lack of moisture.
On my replanted corn, I found that my middle two rows were the last to emerge due to the dry soil the marker kicked up. The row units ran over this dry layer of soil and placed the seeds into it, slightly higher than where the moisture was located.
This was a phenomenon we hadn’t seen in five or six years; rarely do we plant into completely dry soil due to our frequent spring rains and generally high water table at the same time. However, this was another curveball Mother Nature threw at us.
The corn planted April 10 is looking very good; that which survived the fusarium and held on during the April 23-27 planting is OK, but spotty. The majority of the replanted corn in May and the soybeans are looking tougher; some soybean fields were planted in mid-May but did not show any emergence until early June due to lack of moisture, and that was only after two rain events of a quarter-inch each.
Lesson in soil differences
So, why is it we can go from drown-out to drought in a month here in southern Iowa? A little soils lesson, if I may:
Our predominant soil around Humeston is Haig; it is a flat, black, silty clay loam derived from alluvial soil formed on prairies. The top 9 inches is as good as any soil you will find, in my opinion. Below that it’s a different matter, however.
The USDA Natural Resources Conservation Service has done a wonderful job of analyzing soils and placing the data on its website (www.nrcs.usda.gov). One attribute they provide is called “K Sat,” referring to the speed at which water will transmit through a layer of soil if it is saturated. The value is in units of micrometers per second, and is provided for each unique layer of the soil.
Below is a table containing soil layer depths, K Sat values and estimated hours it would take for water to go through each layer. I’ve included Haig as found in Wayne County, and for reference, Webster soil found in Webster County, and Muscatine soil found in Grundy County.
As you can see from the data, water can pass quickly through the top layer of Haig, but hits a roadblock at 48 centimeters (about 18 to 20 inches) — a virtually impervious clay pan. This is why we typically have a high water table at planting on some of our soils here in southern Iowa; there’s little room for the excess water to escape.
Cost advantage increasing
Haig soil sounds like a perfect candidate for tiling, right? This is true, but it has only become potentially cost-effective in the last few years. Soils like Haig would require 4-inch tile on 30-foot centers, costing $1,000 to $1,200 per acre for materials and installation.
At $2.50-per-bushel corn, this did not cash flow, but at $6 per bushel it becomes more viable. For this tile to work, however, it would need to be placed just above the clay pan line, shallower than it is typically placed in soils like Webster or Muscatine.
So, we keep working at it, hoping that we’ll all get timely rains and good weather this summer, to keep our crops growing and on to a bountiful harvest.
Gunzenhauser farms near Humeston.
This article published in the July, 2012 edition of WALLACES FARMER.