Mid-September has arrived. Most sections in the Midwest had the majority of crop acres whimper to the finish line. Most areas within the cornbelt no significant rain to help the soybean crop finish enlarging the bean size. We can say that it was another season had no major moisture fronts moving through the Midwest states to finish filling the moisture profile. In response we saw a steady decline in most major crops as a myriad of challenges piled on top of the number one challenge. So, the harvest season will begin or continue depending on grain moisture levels. The seed corn harvest began three weeks ago and has to be completed before any subfreezing temps arrive. The corn harvest has begun for some of the first planted fields where early maturity hybrids had black layered and field drydown occurred. In northwestern counties where there are more cattle fed, growers are challenges occur when ear corn harvest needs to begin right when the earliest bean are also ready.
The ProFarmer tour came and went with their conclusion of a 172 Bu/A nationwide corn crop. While that may sound good, many growers have somewhat gotten used to whole field yields in the 220 to 230 Bu/A. Breakeven yields with mid $4/Bu corn prices are much higher than the current forecast. Has this price dip been engineered to let feeder and ethanol plants lock in their major grain needs at lower prices?
The Farm Progress Shows
Attendance at the Farm Progress show near Decatur was reported to be good with more foreigners than they have seen in past shows. According to reports from those who attended the numbers from South America and Mexico were record in size. One common remark from those that did not go was that a high percentage of the machinery displays focused on size and subsequently the cost of purchasing and adding to their current inventory of machinery. When the price tag on a new combine and two heads exceeds one million dollars most operators just shake their heads and wonder if their buying habits of their pasts need to change.
Learning that Brazil will now be the largest corn exporter in the world was a surprise. Part of why that it is possible is that their growing season is much longer and they can often produce three cash generating crops in one calendar year. Those can be a first crop of soybeans followed with a corn or cotton crop. If crop number two is corn they can inter-seed a forage crop that they can graze to produce several hundred pounds of gain on grazing cattle or they can read the market price of a new third crop and learn how to grow it. They are not afraid of planting a new crop they know very little about.
In a quick trip to attend a meeting about a hundred miles west of Sioux City where most of the corn acres are irrigated and a high % of them now are permitted by a water agency, which dictate the amount of water they can apply to their fields for the entire season. This is forcing them to consider a new third crop that can produce good yields and make money on limited water supplies. The two major ones which were mentioned were sunflowers for oil and white milo for feed and export markets. The good news about the new grain sorghum varieties is the development of varieties which eliminate the chance of introducing shattercane, which would create a long-term problem in corn.
As a person moves further west and conditions are drier with more windy days, high soil pHs and salt issues intensify and Palmer amaranth incidence could increase weed control tremendously. There may be almost no control means of emerged Palmer plants, at any cost.
Corn Yield Factors
How many factors played large roles in whether a field of corn yielded well vs the opposite. In order could be: #1. Corn on corn vs following soybeans ran; #2. Soils with good soil health produced plants with higher yield forecasts. The Haney scores place a numerical score on each field; fields where the producers have increased infiltrate rates by improving soil health. Such fields absorbed more water for plant use at kernel fill time. This helps the grain fill of both corn and soybeans. 3: Having eliminated compaction at 8-9” and 15-19” permit root growth downward to extract water deeper than three feet. Root dimensions related greatly to parental lines and their root architecture. Shallow rooted varieties just can’t extract enough water and minerals to supply sufficient amounts of both to the above ground tissues of corn plants. 4. How many growers researched and evaluated every mineral or microbial product which has demonstrated the ability help their varieties thru both heat and drought challenged parts of the growing season. Every producer should list of products as helping their plants thru environmentally changed times in each growing season. For whatever reason, high pressure standing ridges or jet stream blocks have changed the moisture delivery systems of ten years ago.
I had the chance to sit with the top pathologist and physiologist from Purdue in early September to discuss the late physiological slide which transformed our stressed, yet still partially green plants, which after two heat waves, went from slight yellowing to completely brown corn plants. He explained that when the plants are trying to maximize photosynthate production in a dry year where N levels are dropping due to the soils being too to form and release nitrogen. Any proteins formed need to utilize N from some source, so will cannibalize any and all leaf tissue for its Nitrogen. Different groups of soils and plant path people are also studying the amount of vascular plugging from bacterial infections plus the plugging which can occur with high iron levels or Manganese/phosphate precipitates. We were also told to examine and consider the role which low moly levels might play in vascular plugging.
The visual evidence of this occurring is the many cornfields which died from both the top and bottom, leaving green leaves in the middle of the plants.
Corn Concerns
By now a sizeable portion of the fields contain plants which have been partially dead for weeks and are at an early stage of decomposition. The stalks are likely start lodging with any strong winds. It would be wise to do a walk thru of your major varieties to see which ones are showing stalk weakness.
Soybeans Status
In most years we hope for and receive one or more rains in August to September to help finish any remaining pod fill which has not happened yet. Due to little to no rain during this time period, expect smaller and unfilled bean pods. With enough stress, the plant hormone abscisic acid will form and top pods may drop.
Soil Testing
Normally it is recommended to follow a four-year soil sampling cycle for all of your fields. Should you still try to maintain this schedule still? If it is done to maintain the four-year cycle, one has to recognize that certain nutrients like K may test abnormally low One may want to retest this next spring after the soil profile has had a chance to normalize after late fall or spring rains.
Stalk Residue Mixtures
It seems oxymoronic to first fear stalk degradation, yet try to speed this process up as soon as the corn fields have been harvested. But that is what many growers have to do, as too much residue can make for poor seed placement next season. More companies have added stalk degrading microbial mixtures which will melt down the stalk residue over the winter. The success of these mixtures will depend on soil temps after harvest and how long the time period after harvest is and if any rain falls to aid in microbial multiplication during the time period. Check field after the microbial application to see how active the bugs are.
Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143 or www.CentralIowaAg.com.