* Farmer sales in Brazil the lowest since 2009/10
* Fundamentals point to lower prices for deals closed in November
* Hoarding slows down Brazil's export line-up
* Brazil to harvest record crop above 110 million tonnes
By Gustavo Bonato
SÃO PAULO, April 11 (Reuters) - Faced with weak international prices and a record harvest, Brazil's soybean farmers have been hoarding their crop in hopes the market will rebound in the coming months, a strategy analysts warn could go badly wrong.
Soybean prices in Brazil have fallen steadily since the middle of last year, when producers were booking advance sales for the 2016/17 harvest, pressured by an appreciation in the local currency and lower prices on the Chicago Board of Trade (CBOT).
Brazil, the world's largest soybean exporter, is on track for a record crop of more than 110 million tonnes. However, the reluctance of farmers to realize losses by selling at lower prices is stemming the flow of beans out of its ports.
Domestic soybean prices fell to 64 reais per 60-kg bag last week, down more than 30 percent from a record high in June, according to benchmark index Esalq/BM&FBovespa SOY-PPAR-BRL, which assesses deals closed at Paranaguá port.
Cushioned by profits from previous seasons, farmers are gambling on a recovery during the volatile April-July period when the new U.S. crop is weather-dependent - despite signs that prices are still falling.
"Producers are waiting for a miracle for new contracts," said Ademir Sari, director at ASP, a local brokerage that sells grains on behalf of farmers in Mato Grosso state.
Estimates from AgRural consultancy show farmers' sales stood at just 49 percent of the total crop as of end-March - the lowest since 2009/10 and below a five-year average of 63 percent.
Hoarding is even more intense in southern states, like Paraná and Rio Grande do Sul, two of Brazil's largest producers. Sales there reached only 27 percent of the crop.
"Here in Paraná, production is based on smaller, more diversified farms. Soybeans are not the only source of income, so producers are fine about waiting for better prices," said Dilvo Grolli, head of the Coopavel cooperative representing 5,000 farmers and handling 640,000 tonnes of grains a year.
Slower farmer sales make it harder for the big international commodities traders to complete their shipping program for the year. A sales executive at one international trader in Rio Grande do Sul said its warehouses were filling up with crops delivered without a price agreed upon.
"We are not going to sell abroad without agreeing a purchase price first, so what may happen is that export volumes from Brazil will not be as big as expected this year after all," said the trader, who asked not to be identified because he was not authorized to speak publicly.
A recent Reuters analysis of port data showed lines were 30 percent shorter this year versus 2016 despite larger volumes being shipped, suggesting traders are working with shorter export programs and avoiding commitments to mid-term loadings.
Fundamentals point to the price outlook worsening. Brazil is in the final stages of an eye-watering harvest and the United States - Brazil's main competitor - is about to plant record soybean acreage as massive global stockpiles of wheat and corn encourage farmers to shift crop.
Rising demand from China, which has grown for 13 years in a row, is also driving interest in soy.
According to Anderson Galvão, head of agricultural consultancy Celeres, the "storage strategy" has paid off four times since the 2009/10 crop, versus two losses and one tie.
That may explain why farmers are betting against prices going down in the future. Soybeans for November delivery settled at $9.48-1/2 per bushel on Tuesday, compared with May soybeans at $9.39-1/4.
However, Galvão does not expect the trade to pay out this year. A study by Céleres projects farmers from Rondonópolis, Mato Grosso, will have to sell at 48.75 reais per bag in November, compared with 60.56 reais if they had sold in March.
For those pursuing the "storage strategy," the loss is exacerbated by the cost of warehousing beans for months.
"It's not worth keeping soybeans this year," Galvão said. He warned that if farmers suffer losses on stored beans, it would hit their cash flow available for future investment in machinery and other new technologies, as happened after the 2013/2014 crop.
Global traders are now focused on the 2017/18 U.S. crop, which is being sowed and will be vulnerable to poor weather for a few months. Any major change in climate patterns - which is not expected at this point - could move prices quickly.
"During the U.S. weather market period, impressions can temporarily overcome the reality," said Pedro Dejneka, head of MD Commodities in Chicago.
According to him, U.S. soybean futures prices hiked during the April-July period 16 times over the last 20 years, even in seasons with heavy supply.
"The market offers some opportunities between April and July ... The probable increases should be used by farmers to close new deals," he added.
For Daniele Siqueira of AgRural, the pace of soybean sales will depend on how long farmers are able to hold out in the hope of getting higher prices.
"Those with deeper pockets are more prone to wait," she said. (Editing by Daniel Flynn and Matthew Lewis)