Farmland boom alters 40-year Iowa corn yield model

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In response to surging Midwest farmland prices, researchers in Iowa are overhauling a decades-old formula used to predict corn yields, which will allow farmers and tax officials to more accurately value property.

The corn suitability rating, or CSR, has long been a Midwestern benchmark to forecast how productive an Iowa farm will be if corn is planted on it.

Since 1971, CSR has been used to set cash-rent rates, help farmers gauge how much to spend on fertilizer and other inputs, and figure out how agricultural land is valued for property tax purposes.

Changes in the formula, which is expected to be released later this year, could raise or lower the value of the state's richest farmland by as much as $2,000 per acre.

The updated equation, dubbed CSR2, will allow farmers, appraisers and others to better understand why some parcels of land perform better than others, said C. Lee Burras, the Iowa State University agronomist who is leading the current effort to further refine the more than four-decade-old model.

"People felt that it was time for an update," said Burras, who is recalibrating the model with researchers from U.S. Department of Agriculture's Natural Resources Conservation Service in Des Moines. "The goal is to create a rating system that anyone can use."

The model predicts how productive a field will be on average over a 10-year period in Iowa, where farmland prices have hit record highs, rising nearly 72 percent over the past five years.

Among other elements, CSR2 weighs topography, the composition of organic matter in the soil, how sandy or clay-rich the soil is and microclimate and weather patterns.

Land is then given a numeric rating from five to 100, with 100 being best. For the best soils, each point roughly translates into $200 per acre or more in land value, according to Burras.

The new formula is able to get a more localized estimate of crop yields, because it takes into account more variables in the soil, said Burras.

In the past, CSR ratings generally were assigned on a state-wide or county-wide level. However, like the old formula, farmers who cross county lines may be vexed, as some CSR2 ratings change from one county to the next.

The older ratings, too, were altered to fit the researchers' knowledge of local farming practices -- a human factor that has made it difficult for modern-day farmers and investors to replicate the researchers' math.

The current formula will take out that human element, Burras said. "The goal is to create a rating system that anyone can use to calculate their own CSR," he said.

So far, Iowa tax officials anticipate seeing only subtle changes on the statewide and county-wide ratings, said Julie Roisen, Property Tax Administrator for the state of Iowa.

On the local or individual parcel level, however, "that's where we're expecting the value may change," Roisen said.

Burras said that CSR2's early findings have shown minor differences with the original CSR of between two to 10 points in much of Iowa.

Sizeable theoretical variances - up to 70 points -- have been found near urban centers. Those lands were never covered by the original rating system, Burras said.

Though Iowa is considered a leader in agricultural circles for this sort of research, several Midwestern states with land-grant universities have developed similar crop productivity indexes.

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Arizona  |  January, 08, 2012 at 02:36 PM

They shouldn't even be CHARGING property tax on farmland. Thanks to property tax, food prices are much higher, and many family farmers have lost their land to agribusiness, which hurts the health of all of us. It's time to stand up to this egregious denial of the right to property lawfully acquired. Property tax means there is no such thing as property ownership in the US. It all belongs to the government.

Gary Cook Jr.    
Lake Santee, Indiana  |  January, 08, 2012 at 02:50 PM

These rich farmers need to pay WAY more in property taxes. They don't pay their fair share. Homeowners and businesses are subsidizing these millionaire farmers and their highly valuable income property, namely commercial farmland. Why would these super rich midwest farmers not think their taxes would go up when the value and the income associated with their land doubled due to the corn ethanol scam?

jim Perry    
Arizona  |  January, 10, 2012 at 11:13 AM

I am ok with eliminating the Property Tax for farmers, AKA Sod Busters, as long as we eliminate the subsidies. If they cant farm with out them then they should quit farming.

Arizona  |  January, 11, 2012 at 09:42 AM

I agree. Farm subsidies should be eliminated. I used to run a goat ranch. A census worker came onto my property one day and wanted to ask me questions about my ranch. I refused to answer any questions. He said, we need the answers to know how much the various states should get in subsidies. I told him, WRONG ANSWER. I don't approve of subsidies, and I won't accept them. You are trespassing. You need to leave! He did.

Jon Hjelm    
Spencer Iowa  |  January, 14, 2012 at 12:37 PM

Some CSR's have alreay been adjusted. Some Average CSR's were reduced 6-7 points in Dickinson County Iowa. Very few states use CSR. Most states use a PI - Productivity Index. MOST people were fine with the current system. CSR's are a great guideline. Other factors need to be taken into consideration, appearance, tile, tile outlet etc. when looking at a valuation on a tract of land. Sorry Mr. Cook this article is about soil ratings not unknowledgeable non-farm jibber. If you city folks took care of your property and paid your bills, farmers and landowners would not keep getting the tab to fix your city streets and schools.

Jon Hjelm    
Spencer Iowa  |  January, 14, 2012 at 12:52 PM

Ethanol scam ????? - Folks get your facts straight. Please come to the Midwest and do some fact checking. Ethanol production creates more food. Ethanol burns clean - not like the petroleum additives. The Car Czar who has been on CNN MSNBC CNBC bashing ethanol - pled guilty and paid millions in federal fines to keep his seat on Wall Street. US gov't promoted high gas prices - no drilling - causing more shipping costs have raised food prices. You can blame the Global warming folks flying around in their private jets, the No Drill for oil folks, the Lets regulate trucking folks. Ethanol is not the total answer but is part of a solution. We have not lost any young soldiers lives invading up an ethanol plant. We have not spent BILLIONS occupying the Midwest corn fields. Get some better policy or leave us alone.

Texas  |  August, 22, 2012 at 04:37 PM

EWG Farm Subsidy Database. Every farmer is in there.


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