Flex Your Knowledge

11:45AM Mar 08, 2014
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ken ferrie

When reviewing yield maps with farmers, there is one variable that consistently impacts yield in a big way: hybrid selection. There are many factors to balance when selecting hybrids each year. Don’t just base your decisions on how a hybrid performed in a test plot the next county over, but rather, have your own data, preferably from multiple years, to help root your decisions.

I realize this is tricky, especially as seed companies increase the rate they develop new hybrids and rotate technologies. Work with your seed dealer to identify the hybrid characteristics that will yield the greatest success, and take advantage of the numerous tools and programs offered through your seed company.

It’s an exciting time in farming because not only are we talking about the right hybrid for the field, but the right hybrid for the zone and being able to change hybrids on the go. In 2013, I worked with some of my farmer-clients to help make the variable-hybrid planting pro­cess mechanically pos­­si­ble. Even though we can do it, I’m not sure we have access to all of the knowledge we need to truly maximize yields.

Focus on ear type. I’ve been heading up the Farm Journal Test Plots for 27 crop years, and have been planting and overseeing plots in general for even longer. Every year, we try to eliminate all of the variables so we can drill down and truly learn what practices add up to more yield.

We have studied how hybrids respond to population, nitrogen timing, pests and more. One characteristic has captured my attention right now—ear type.

Most seed companies label hybrids as semi-flex, which is true because all hybrids will flex. But the degree of which they flex can cause radical swings in yield.

Based on my observations in recent years, the riskiest hybrid seems to be a full flex. Yes, it will flex out to increase yields, but it will also flex the opposite direction when experiencing stress, and this includes stress from population, nitrogen and water.

Flex ear hybrids can’t take stress caused by overplanting or under-fertilizing. Determinant ear hybrids need to be pushed to maximize yield and handle more stress. Semi-flex hybrids split the middle.

Leaf structure matters. There are three keys factors to yield: sunlight interception, water and nutrient uptake. An upright leaf structure harvests more sunlight and will respond in yield if sunlight is the limiting factor. Floppy leaf hybrids will maximize leaf area index at much lower populations than upright hybrids. Semi-upright hybrids split the middle.

When water consumption is a concern, lower the population to lower water usage. Flex ear hybrids can compensate for lower ear count. Floppy leaf structure will maximize leaf area index at lower populations. Narrow row spacing reaches maximum leaf area index more quickly to harvest more water.

When lack of sunlight interception is a concern, use upright leaf structure to let sunlight deep into the canopy. Use a determinant ear hybrid to allow you to push populations to achieve maximum leaf area index and a higher ear count. Narrow rows will capture more sunlight.

When fields have high amounts of variability going from surplus water to droughty soils, use semi-flex ear types and variable-rate planting to mitigate the risks. Use semi-upright leaf structure to maximize sunlight and drought protection. Also, narrow the rows to help with both.

For water management, narrow rows and variable-rate populations are a great combination in variable soils. Plant high populations in heavy ground to use extra water. Plant lower populations in light soils to conserve water. Use a semi-upright leaf with a semi-flex ear.

We follow this basic protocol to evaluate hybrid flex:

1. Plant each hybrid to two ranges, specifically an ultra low population and a recommended population provided by the seed company.

2. Harvest the ears of each hybrid at the two populations and compare. This will allow you to see which hybrids flex up and down the most. That will help frame your future decisions on how to manage that hybrid.

As Farm Journal Field Agronomist, Ken Ferrie brings the System Approach to life in dozens of test plots each year. Contact Ken:

Email: [email protected]

Website: www.FarmJournal.com/ask_an_agronomist

The information provided is not a replacement for receiving personalized agronomic consulting.