Annual "Gold Book" Report on Cultural Practices and Management Systems for Corn in Wisconsin is now available

Photo by Roger Schmidt

Agronomy is the science of land management. Agronomists generate, integrate and apply science-based knowledge and principles to crops grown for food, feed, fiber, and fuel that are efficient, environmentally sound, and sustainable for future generations. The mission of the Wisconsin Corn Agronomy program is to answer corn management questions expressed by Wisconsin farmers and industry.

The Wisconsin Corn Agronomy program annually plants and harvests 12,000 to 13,000 plots at 14 locations in Wisconsin. Of these plots, about 3000 are harvested for forage with the remaining harvested for grain. Corn forage and/or grain yield, quality and other agronomic traits are measured on all plots.

Roughly half of the plots involve the Wisconsin Corn Hybrid Evaluation program, The best way to deliver technology to the farm-gate is through hybrids selected by farmers for various traits (i.e. pest resistance, lodging resistance, quality, etc.). Selecting adapted, high-performing hybrids often means the difference between profit and loss. Results of of this work are published every year in November and can be found here.

The other half of the program involves research on farmer management decisions. The results of this work are published every year in February and can be found here. Specific research objectives of this program focus on management decision-making regarding crop productivity, quality, and production efficiency including hybrid selection, rotation, tillage systems, and replant and yield loss damage assessments. Emphasis is on impacts of cropping practices on grower profitability, the environment, and natural resource conservation.

Below is a list of projects conducted during 2022.

Full report

Map

2022 Weather for Arlington 
2022 Weather for Marshfield

Hybrid evaluation
    01 Optimum hybrid maturity at various locations
    01 Syngenta hybrid evaluation for silage
    01 Prairie Hybrids evaluation for silage

Planting systems
    02 Plant density
    03 Date of planting

Wisconsin Crop Rotation Trials
    09 Alfalfa-Corn
    09 Corn-Soybean
    09 Corn-Soybean-Wheat
    09 Alfalfa-Corn-Oat-Soybean-Wheat

Pest control
    10 Xyway fungicide

Product evaluation
    11  Elicit - Best a (biostimulant-phytosterol)

Soil fertility
    12 Envita

Plant variability
    16 Sweet corn defoliation

17 Strip-Tillage

19 Agrosystems - Fractional replication

We have done our best to see that the experiment design and data collection to date is complete, timely and free from errors. However, if you detect an error in these results, please call it to our attention. These reports are copyrighted. The information presented in these reports are for the purpose of informing farmers and cooperators in industry of the results of research. The cooperation of other faculty and staff and the support of funding agencies and industry are gratefully acknowledged. The information presented in this report does not constitute recommendation or endorsement.

2022 Wisconsin Corn Hybrid Performance Trials: Grain • Silage • Specialty • Organic

 This year marks the 50th year of corn hybrid performance evaluation conducted by the Wisconsin Agronomy Department, the Wisconsin Crop Improvement Association, and the seed industry. In 1973, the first Wisconsin public corn performance trials were conducted by Elwood Brickbauer. Trials were grown in southern Wisconsin at Janesville, Lancaster and Platteville. In northern Wisconsin, trials were established at Antigo, Ashland, Hancock, Marshfield, Spooner, and Waupaca. The average yield of the first trials was 121 bu/A. Over the past 50 years, 18,773 hybrids have been evaluated at various locations in Wisconsin. In 1995, the corn silage hybrid evaluation program was initiated. Hybrid selection is a key decision made by farmers and historically is important for delivering new technologies, pest resistance and increased yield and profitability to the farm-gate.  The purpose of this program is to provide unbiased performance comparisons of hybrid seed corn for both grain and silage available in Wisconsin.  

The 2022 growing season at most southern sites was similar to the 30-year normal for Growing Degree Unit (GDU) accumulation and precipitation. In northern Wisconsin, GDU accumulation and precipitation was less than normal. For most of the state, planting progress was similar to the average with 50% of the acreage planted by May 10. An exception was northeast Wisconsin which had somewhat delayed planting. Most trial plots were established by early May. Stand establishment was good to excellent at all locations. Ear size was larger than normal. Tar spot, Phyllachora maydis, increased throughout the state and was significant in southern Wisconsin, however, in most cases it was too late to affect yield. Good growing conditions continued into late-fall with a killing frost occurring in late October. Silage and grain moisture was higher than normal. Little plant lodging occurred at most trial sites. Little disease and insect pressure were observed within most trials.

Results for the 2022 growing season can be found at: http://corn.agronomy.wisc.edu/HT/2022/2022Text.aspx.

 

 

 

 

 

 

 

Corn Pollination: What does success look like?

Corn anthers on the tassel (male).

Awww ... sex in the corn field. It's happening all around us. For the next few weeks, pollination and fertilization of corn ovules will be occurring throughout Wisconsin. The success of pollination will determine management decisions as the growing season progresses. 

Pollen shed begins near VT and is essential for grain development. During this 1 to 2 week pollination period, each silk must emerge from the ear husk, and a pollen grain must land on the ovule and fertilize it for a g kernel to develop. 

When a pollen grain lands on a silk, a pollen tube is initiated. The pollen tube grows within the silk to the ovule where fertilization occurs and the kernel embryo is formed. A second fertilization also takes place that results in the formation of the endosperm. Immediately following fertilization, an abscission layer forms at the base of the silk, restricting entry of genetic material from other pollen grains.

Pollen sheds from the male flowers on the tassel for 5-8 days and is dependent upon temperature, moisture and time of day (peaks around mid- to late-morning or early evenings. Pollen grain is viable for 12-18 hours (less in higher temperatures) after it drops from the tassel; most pollen falls within 20-50 feet of the plant. 

"Nick" is the period when pollen shed (VT) coincides with silk receptivity (R1). Poor nick can result from hot and dry weather. Silks can be delayed and dehydrate, which hastens pollen shed and causes the plant to miss the window for pollination.

Corn silks on the ear (female).

Silks will grow for 3-5 days or until pollination occurs. Silks will turn brown once outside the husk. Stresses that reduce pollination can result in an ear with a barren tip called a "nubbin." Each kernel has a noticeable point where the silk was attached; the kernel is surrounded by paleas, lemmas, and glumes. 

After an ovule is fertilized, cell division occurs within the kernel for ~7-10 days. After cell division is complete, the cells fill. The outer part of the kernel is white, and the inner part is clear with very little fluid. The embryo is not yet visible. The kernel endosperm fills with photsynthate, most of which is produced by the leaf on the same node as the ear shank; this ear leaf provides up to 60% of the total grain yield.

There are two techniques commonly used to assess the success or failure of pollination. One involves simply waiting until the developing ovules (kernels) appear as watery blisters (the "blister" stage of kernel development). This usually occurs about 10 days after fertilization of the ovules.

Another more rapid means can be used to determine pollination success. As described above, each potential kernel on the ear has a silk attached to it. Once a pollen grain "lands" on an individual silk, it quickly germinates and produces a pollen tube that grows the length of the silk to fertilize the ovule in 12 to 28 hours. Within 1 to 3 days after a silk is pollinated and fertilization of the ovule is successful, the silk will detach from the developing kernel. Unfertilized ovules will still have attached silks. Silks turn brown and dry up after the fertilization process occurs. By carefully unwrapping the husk leaves from an ear and then gently shaking the ear, the silks from the fertilized ovules will readily drop off. Keep in mind that silks can remain receptive to pollen up to 10 days after emergence. The proportion of silks dropping off the ear indicates the proportion of fertilized ovules (future kernels) on an ear. Sampling several ears at random throughout a field will provide an indication of the progress of pollination. 

If pollination is poor, then harvest can occur anytime. If pollination is fair, then leave for silage harvest. If pollination is good, then normal management of the field can occur for either silage or grain uses.

Further reading

 Methods for Determining Corn Pollination Success

Broeske, M., and J. Lauer. 2020. Visual Guide to Corn Development. University of Wisconsin Extension. Nutrient and Pest Management Program, 72 pages.