Dry conditions threaten Federico Rolle’s soya crop

I have never seen such a change in rainfall within the same cropping season. This cropping season in Argentina started with rainy conditions (the El Niño effect), but over recent days it has reverted to a drying effect (La Niña).

At my farm in Bigand, the 12mm of rainfall on 31 January was only half of the predicted amount. Another 20-30mm is predicted for 14 February, which if it does fall would bring the total to 44mm in the past 50 days. This is well down on the 130mm expected over the same period in a normal year.

Soya beans are still tapping into the soil moisture reserves, but there are already signs of water shortage in plots with lower production potential. It is vital that we do see rain next week, as the crop is at the grain filling stage, a time when the plant’s water requirement is higher and a time that defines much of the yield potential.

Soya beans generally show a very good development, but the combined stress from lack of rain and high temperatures, is beginning to affect the yield potential and is visible as leaf loss (up to 50% from the base), plus flowers and pods. However, if the forecasted rains do come, I still have expectations of reasonable yields.

Another issue highlighted this week is a severe attack from the velvetbean caterpillar (anicarsia gemmatalis), eating the seeds in the pods. Levels of 3-5 caterpillars greater than 1.5cm in length is the threshold for treatment with a cypermethrin-based insecticide.

In bad weather conditions, we add an increase of 25% to direct costs of production measured in dollars. Combined with tax hikes and the value of the dollar, the future viability looks dark for medium-sized farmers such as me.

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