Cooling and abrupt change in agrometeorological conditions at the end of March

After the above-normal temperatures at the end of the second and the beginning of the third ten-day period of March, during the period (20–26 March) a cold spell and an abrupt change in the agrometeorological conditions are expected. By the end of the period, the forecast values of the average daily temperatures will be significantly below the norm for the third ten-day period and, in most of the field areas, also below the biological minimum required for the vegetation of the autumn-sown crops. The expected cooling will lead to a slowdown, and in parts of Western Bulgaria, where snowfall is forecast, to a short-term cessation of the vegetative processes in the winter cereal crops and rapeseed. At the beginning of spring, wheat will predominantly be in the tillering stage, and rapeseed – at the beginning of branching formation.

During the second half of the period, negative minimum temperatures are again forecast, with a risk of damage to some of the fruit crops that have entered the flowering stage – almond, apricot, peach. Frost damage to some early-flowering fruit species (apricot, almond) was recorded at the end of the second ten-day period of March in places in the eastern and southeastern regions of the country.

Favorable conditions for carrying out seasonal agrotechnical activities will be present at the beginning of the period. The following period coincides with the optimal agrotechnical time frame for sowing sunflower in Southern Bulgaria.

During the second half of the period, in order to reduce the risk of damage to fruit trees that are advanced in their development, smoke generation can be applied – one of the most widely used measures, which achieves a thermal effect of 1 to 3°C. Where possible, preventive spraying with registered products against frost and freezing is advisable.

Source: NIMH