It has almost become a summer ritual, the publication by Lanworth of crop forecasts which disagree substantially with the official line.

Last year, investors had to wait until July before the analysis group, which uses vegetation mapping and the like gained from satellite imagery for its forecasts, dropped its bombshell that the US corn crop would come in at 12.90bn bushels, below the US Department of Agriculture's then-forecast of 13.47bn bushels.

(The end result was 12.36bn bushels, below both but nearer Lanworth.)

On Friday, Lanworth came in with an estimate for the US 2012 crop of 13.645bn bushels, below the USDA forecast last month of 14.790bn.

'Pictures of stressed corn'

The idea that the US crop faces an uphill struggle meeting USDA hopes was given credence by forecasts showing that the Corn Belt faces elevated temperatures this weekend, into the 90s Fahrenheit, with little rain, and with conditions ahead hardly looking ideal either.

WxRisk.com's reading of the latest models showed that "so far it looks like middle and late June is turning out to be exactly as hot and dry as I forecasted last week", with a cold front staying in Canada.

"As long as this cold front stays to the north, most of the Plains and all the Midwest and the Delta regions stay dry and turn hot, except maybe for North Dakota and northern Minnesota."

And this when some crops are already showing signs of difficulty, (with concerns moving into the livestock sector too).

"Reports and pictures of stressed corn and soybeans continue to come into our office from Nebraska to Ohio," Paul Georgy at broker Allendale said.

Poor macro-picture

The impact was to hand Chicago corn futures gains on a dismal day for risk assets, as investors scarpered ahead of a weekend which will bring a raft of Chinese data.

These statistics are seen likely to prove unpromising, given China's move on Thursday to lower interest rates for the first time since 2008 to support its economy.

Shares eased in Europe, if edging higher on Wall Street, while the safe haven of the dollar leaped 0.6%, adding pressure to dollar-denominated exports such as many commodities.

The average commodity, as measured by the CRB index, stood 0.7% lower in late deals, when Brent crude was firmly back below $100 a barrel.

China buys

However, new crop December corn stood at $5.42 a bushel, up 1.0%, with some half an hour of Chicago's electronic trading session to go. The old crop July lot was up 0.8% at $5.99  ¼ a bushel.

And Lanworth, in forecasting the US soybean harvest at 3.019bn bushels, below the USDA forecast of 3.205bn bushels, did its bit to support the oilseed too.

While the new crop November soybean lot fell 0.7% to $13.31 ½ a bushel, this was better than some other crops.

The old crop July lot actually managed nearly to hold its ground, losing 1.0 cents to $14.27 a bushel, supported by a fresh round of export sales, and keeping the pressure on America's already tight soybean supplies.

Egypt bought 120,000 tonnes of old-crop soybeans, and China 60,000 tonnes, on top of 350,000 tonnes of new crop.

'Just tight enough'

The resilience did not quite spread to wheat, which continued to feel pressure from the US winter crop harvest, at a time of year when prices often bottom out in Chicago.

There, the July contract lost 1.7% to $6.31 a bushel.

That said, there are some weather alerts on the horizon, such as dryness in China and parts of Western Australia, to balance out improvements such as that noted in the French soft wheat crop, which was rated 72% in good or excellent condition by FranceAgriMer, up two points on the week  - and far higher than the 24% during drought last year.

"It seems that the potential supply of wheat worldwide is just tight enough to keep market players interested in anything that could affect production," grain traders at a major European commodities house said.

Paris wheat itself ended unchanged at E209.50 a tonne for November delivery, with London wheat for November adding 0.2% to £157.00 a tonne, all helped by the strong dollar.

Sugar sweetens

The strong dollar did its bit to dent prices of many soft commodities, sending New York cotton for July down 0.9% to 73.20 cents a pound in late deals, while July coffee closed down 0.7% at 155.60 cents a pound.

But raw sugar bucked the trend, adding 1.1% to 19.98 cents a pound for July on fears of rain hampering the Brazilian crush, and sugar handling at ports, where ships on uncovered docks must close their doors when it rains to avoid cargo spoiling.

"Rain may be an issue short term in Brazil, preventing crushing and hindering loading," Nick Penney at Sucden Financial said.

However, he added: "Long term it will benefit the crop. long term it will benefit the crop.

"There is still more than enough sugar around and prices must fall further to attract buying and restocking by end users to absorb some of the surplus now."