The slowdown forecast for farmland prices in the southern US Plains may already have struck in the Midwest, where values put in their worst performance in four years, amid fears over prospects for the farm machinery market too.
Farmland values in states including Iowa, the top corn and soybean producing state, and second ranked Illinois showed no growth in the April-to-June quarter over the same period a year before, the Federal Reserve's Chicago bank said.
"The last time there was no quarterly increase in agricultural land values was in 2009," the bank said, in a report which showed a decline in Illinois prices.
And while year-on-year growth remained strong, at 17%, the bank forecast that this figure looks set to decline, with lenders surveyed expecting values to remain flat.
"While the farmland values on a year-over-year basis still appeared to be soaring, changes in farmland values on a quarterly basis may be presaging shifts in the year-over-year pattern in the latter half of 2013."
The comments follow a report from the Kansas City Fed saying that while values in its area, which includes Nebraska and the top wheat-growing state of Kansas, continued to climb in the latest quarter, many bankers feel prices may now "have peaked".
The concerns reflect ideas that the weaker crop prices expected for this year's crop will, in depressing returns, reduce the appeal of farmland, and farmers' own financial firepower for deals.
Furthermore, data from both Chicago and Kansas City banks shows the first rise in interest rates in two years – albeit to levels still low by historical standards.
"The uptick in interest rates on farm loans may mark an important shift in the district's agricultural credit conditions," the Chicago Fed said.
There was a feeling that "the anticipation of lower crop revenues - especially when combined with potentially rising interest rates on farm loans - portended softness in future farmland values".
'Higher and higher unsold inventory'
Ideas of a market slowdown were supported separately by data from Creighton University showing the rise in farmland prices across major agricultural states, including Illinois, Iowa and Kansas, decelerating in August for the eighth time in nine months.
"Lower farm commodity prices are slowing growth in farmland prices," Ernie Goss, Creighton economics professor said, adding that he expected "farmland price growth to continue to weaken as agriculture commodity prices soften."
The weakened agricultural economy had already pushed the farm equipment sector into decline, with a market index falling to 49.2 to stand below the neutral level of 50.0 for the first time in four years.
"I am concerned that agriculture equipment dealers may find themselves with higher and higher unsold inventory," Professor Goss said.
"The direction we are seeing in agriculture commodity prices, while helpful to livestock producers, is pushing farmers to pull back on their equipment purchases."
'Don't see Paul Volcker'
The comments follow a lively debate at a Deere & Co investor meeting on Wednesday, at which analysts repeatedly questioned the tractor maker's forecast of only a small fall in 2014 in farm cash receipts, a key indicator of machinery demand.
However, there are few expectations of a 1980s'-style industry collapse, which was fuelled by a rapid jump in interest rates.
"I can't see any way this time that people are going to have to be paying more than 20% on their borrowings as they did last time," a leading agricultural commentator told Agrimoney.com.
"I don't see Paul Volcker [then Federal Reserve chairman] standing on the sidelines."