Poor quality seed added to the trials of Argentine farmers who saw their corn and soybean sowings further delayed by rains and flooding which wiped out some crops already planted.
The Buenos Aires grains exchange flagged "widespread problems" with the germination rates of soybean seed on offer this season in Argentina, the third-ranked exporter of the oilseed, whose supplies are being eagerly anticipated by buyers following a drought-hit US crop.
While the issue was not expected to curtail an expected 4.5% expansion in soybean area, it could "impact negatively" on the crop "if no planting density corrections are made" by growers, the exchange said.
The problem adds to rain-delayed sowings which, for corn and soybeans combined, have left farmers well over 2m hectares behind the sowings pace achieved last year.
'Flooding in large areas'
For soybeans, farmers have planted only 3.6%, or some 700,000 hectares, of the 19.7m hectares of soybeans expected to be sown for the 2012-13 harvest.
This leaves growers 8.9% - or 1.75m hectares - behind last season's pace, and reflected farmers' ability last week to plant only some 300,000 hectares because of heavy rains.
"This delay in plantings is the consequence of heavy rainfall recorded during the beginning of the week," which landed "fairly abundant rainfall over much of the central region of our agricultural area," where current sowings activity is largely concentrated.
A strip running from Cordoba through to northern Buenos Aires provinces received 50mm-130mm of rain, prompting "not only delays in sowing, but causing rivers and streams to break their banks, and flooding in large areas".
The rains had extended delays in corn seedings too, with farmers making a "slight advance" in plantings over the past week, getting 3.2% of the forecast 3.4m hectares of seedings in the ground.
Total sowings had reached "only" 40% complete, compared with a figure of nearly 57% a year ago, equivalent to a lag of some 570,000 hectares.
And even of those fields which were planted, some in the sodden central belt were lost to flooding, with others seeing their development "compromised" by damage to the soil structure.
The impact of the floods on corn prospect is especially severe given that it is typically earlier sown than soybeans, with only a small window of seeding opportunity left in December, given that growers typically avoid sowing in November for fear of crops pollinating at the period of peak summer heat damaging at this sensitive stage of development.
Furthermore, the rains have leached away many of the nutrients farmers had applied in preparation for corn crops, a fertilizer-hungry crop.
Indeed, the exchange, flagging "great uncertainty among producers", noted the likelihood of many corn areas yet to be planted, or requiring reseeding being sown with soybeans instead.
'Still in very good condition'
However, the early stages of the wheat harvest had gone largely to plan, being focused so far in northern areas where rainfall was more modest.
Indeed, growers harvested 1.9% of the crop to reach a 6% completion rate so far, at an average yield of 1.12 tonnes per hectare.
The exchange stood by a forecast of a 10.12m-tonne Argentine wheat harvest, flagging that wheat crops in southern areas of the major producing province of Buenos Aires, were "still in very good condition thanks to continuous moderate-intensity rainfall".