Investors were caught short by the last key US Department of Agriculture data.
They were reluctant to be in the same position for the next lot, due on Tuesday.
That helped agricultural commodities return from a long weekend in strong form, on what was not the most promising day for risk assets.
There were two reasons to think that crops might fall. (And, indeed many risk assets did decline, with shares down 1.5% in Tokyo, 1.6% in Seoul and 0.9% in Shanghai.)
The first was US non-farm payrolls data on Friday, when many markets in the US and other Western countries were closed for Easter, which showed the world's biggest economy added 120,000 jobs in March, below economists' expectations of a 205,000 increase.
The second was Chinese inflation data on Monday, which rose to 3.6% last month, up from 3.2% in February.
Sure, the figure was well below the 4.5% recorded in January, but it appeared to indicate reduced elbow room for Chinese policymakers in easing monetary policy, and keeping up the pace of the world's second-ranked economy.
Chinese prices rise
But, besides a background of waning correlations between risk assets, with the CRB commodities index for instance moving a little out of time with the S&P500 index of US stocks, crop investors had at least two reasons to be cautious about selling.
The first was the reaction of China's own crop markets to the inflation data. While Shanghai stocks fell, Dalian and Zhengzhou farm commodity futures broadly rose, the exception being best-traded September Dalian corn, which fell by 1 yuan to 2,454 yuan a tonne.
The less traded spot May corn contract added 2 yuan to 2,467 yuan a tonne.
And soyoil for September gained 0.5% to 9,996 yuan a tonne, (cross 10,000 yuan a tonne earlier for the first time in six months), while soybeans themselves for September closed up 0.1% at a 4,642 yuan a tonne, a fresh high since autumn 2008.
On the Zhengzhou, sugar for September soared 2.0% to 6,816 yuan a tonne, while cotton added 0.3% to 21,240 yuan a tonne.
'The next market-moving event'
A second reason for Chicago investors to tread carefully about selling out was the prospect of the USDA's latest monthly Wasde report on world crop supply and demand, on Tuesday.
That "will be the next market-moving event", Mike Mawdsley at Market 1 said, noting that "traders will watch to see how much the South American crop will be cut", with many other analysts already having expanded ideas of damage to soybean crops from drought.
And, having been caught out by USDA data on US sowings and grain inventories on March 30 which turned out broadly bullish, investors appeared less willing to go short this time.
Furthermore, weather conditions in the US are no longer as benign as they were, with northern states receiving snow over the weekend, including more than eight inches in parts of Montana.
And there is more cold to come if only temporarily, according to WxRisk.com.
"On the morning of April 12 temperatures across most the Midwest will be below freezing," the weather service said.
"A heart of the cold high will be right over the Midwest.
"Three days later, by April 15, temperatures over all of the central and the lower Plains as well as the entire Deep South and most of the Midwest will be near 80 degrees Fahrenheit."
'Best performance since December'
So in Chicago, investors gave crops the bullish side of the doubt early on Monday, taking May wheat 0.3% higher to $6.40 a bushel, and May soybeans up 0.2% at $14.37 a bushel as of 09:15 UK time (03:15 Chicago time).
May corn added 0.5% to $6.61 a bushel, extending its premium over wheat.
And in New York, cotton gained 0.7% to 89.18 cents a pound.
However, in Kuala Lumpur, palm oil hit a fresh one-year high of 3,623 ringgit a tonne, only to fall back to 3,590 ringgit a tonne, down 0.4% on the day.
But then a little profit-taking was tempting, given the vegetable oil's performance last week (which included trading on Friday).
"Palm oil recorded its best weekly performance since December with an almost 5.0% gain in response to a damaging South American drought and US data showing farmers will plant less soy,? shifting demand for the tropical oil," Ker Chung Yan at Phillip Futures said.