The rains of recent years repeat large surpluses that begin to correlate with increasing levels of losses in the region's most vulnerable and most important crop: soybean.
Each consecutive year that passes with heavy rains, multiply the losses of hectare of soybean. For three years, the losees have typically gone from 3% to 5% and in the last cycle up to 9%.
In the first half of 2017: 1,000 mm were already registered in the south of Santa Fe and the average of the region exceeds 700 mm.
What is the average rainfall in the region?
Analyzing the city of Rosario in the southeast of Santa Fe, the rainfall average of the last 50 years shows 1,035 mm. The minimum was in 1974 with 660 mm, and the maximum in 2012, with 1,640 mm (Source: Agroclimatic Atlas of Guillermo Murphy, (FAUBA)). However, if we take into account the values of the meteorological station of Rosario of the network of stations of the BCR, the last 10 years give a greater volume: 1.208 mm. The minimum of 700 mm was recorded in 2008 and the maximum value in 2012 with 1,910 mm.
If we analyze Marcos Juarez (a city of the east of Córdoba), there is an average of 885 mm in 107 years. From this set of data, we rescued the minimum measured in 1929 with only 508 mm and the maximum in 1991 with 1,540 mm. (We appreciate the kindness of this data to JOLAP SA consultant).
How much more does it rain?
2012 was the strongest year of rain in the last six-year period. It rained more than 1,700 mm in many localities. The average of the region was between 1,400 and 1,500 mm. 450 mm more in the whole region.
In 2013, average rainfall values were between 700 and 800 mm.
In 2014, the northeast was overwhelmed by accumulations of up to 1700 mm. The averages were around 1300 and 1400 mm. They were almost 400 mm more.
The 2015 left an extra 300 mm above the average values. The region received an average of 1,200 to 1,300 mm annually.
Year 2016, annual rainfall showed peaks of up to 1,700 mm. The average of the region was between 1,200 and 1,300 mm. They were 300 mm more than the average in the whole region
How much soybean area could be lost this year?
The problem of water excesses is a cumulative problem. The consequence of rainy years begins to appear in the statistical series as a significant problem in a crop as sensitive as soybean.
With flooding for three days in the early stages (2-3 leaves) yield losses of 20% are attributed to a reduction in plant population and restricted growth.
In more advanced stages (V4 and R2), 48 hours of flooding caused a yield reduction of 40 and 55%, respectively.
It is evident that the crop is more tolerant to waterlogging during vegetative than reproductive stages, and to avoid loss of yield, water must be removed in less than 48 hours.
Of course, the intensity and timing of the rains are fundamental to define the impact on the crop in the region. But the fact of starting with napas a few inches deep in the soils of the region is something that already puts the soybean in a serious situation of disadvantage.
For all this, if the rainfall pattern exceeds annual rainfall margins by 200-300 mm this year, it will be very difficult for soybean losses to be below 8-10%.