Farmer Focus: Flooding could hit soya yields by up to 30%

We have seen significant rainfall over the past weekend in the area that I farm, with 280mm in the south of Santa Fe, with an average 140mm in the wider region.

This volume of water is extremely valuable to soya bean crops as it will help define performance. It is also a great contribution to the crops that were planted in December or after wheat, which have been slow to grow.

While the positive impact of these rains on yields are evident, several low-lying areas have been flooded and there are now specific disease threats due to the excess water, which could be see yield losses of between 10% and 30%.

Given those new conditions for developing soya bean crops which are at their critical pod formation and grain-filling stages, the expected yields of 3.5t/ha and 4t/ha could still be achieved, as long as there are no periods of significant stress in the future .

However, the early-maturing soya that was drilled earlier has already irretrievably lost yield potential, as they are at the advanced stage of grain filling. The second soya bean crops (planted after wheat) are starting to flower, so still have potential.

A striking feature of this year’s campaign, besides the emergence of several weeds resistant to glyphosate application, has been significant pressure from Helicoverpa gelotopoeon (South American bollworm moth) and Rachiplusia nu (sunflower looper), which in my case required two applications of insecticide. Some of my neighbours have to apply up to four times.

In summary, the increasing presence of resistant weeds, insects and disease pressure, rising costs of fuel and high inflation (30% per year) means that production costs will reach 1.7t/ha, which if you add another 1.7t/ha of rental, results in a break-even point of 3.4t/ha, too high to generate enough to pay back bank loans and recover working capital that has been lost during the past three years of poor margins.

More from Federico Rolle

More from all our Arable Farmer Focus writers

See more