Agrometeorological forecast for May

During the first ten-day period of May, the development of agricultural crops will proceed at a slower pace, with mean daily temperatures below the climatic norms. At the beginning of the month, in the higher basin fields, the possibility of frost formation cannot be excluded, which should be taken into account when transplanting vegetable seedlings.

After the unusually dry conditions for the beginning of spring, the rainfall that occurred in the second half of April, exceeding 50–60 l/m² in many parts of the country, contributed to overcoming the soil moisture deficit in the autumn-sown crops. The forecast rainfall during the first ten-day period of May will maintain good levels of soil moisture reserves in the 50 cm layer – above 75–80% of field capacity. This rainfall will have a favourable effect on the winter cereal crops, which are in the reproductive stage of their development, with increasing requirements for soil moisture. During the first ten-day period, wheat will pass through the stem elongation stage, the transition to heading, and the beginning of heading in crops in places in the Danube Plain and in the extreme southern regions.

After the cool weather for the season during the first half of the second ten-day period, an improvement is forecast, with normalization of thermal conditions and acceleration of the vegetative processes in agricultural crops.

During most days of the second half of May, the development of winter cereals and sown spring crops will proceed at an accelerated pace, under above-normal temperatures. In maize and sunflower, leaf formation will take place. At the end of May, in sunflower sown within the agrotechnical time frame, the formation of the inflorescence will be observed.

During the third ten-day period, rainfall of economic significance is expected, which will ensure the increased water demand of the winter cereal crops, in which grain formation and filling will occur. During this period, a probability of hail and a risk of damage to agricultural crops is forecast. For fruit and vegetable crops affected by hail, it is recommended that treatment with copper-containing fungicides be carried out at the first opportunity in order to accelerate wound healing and reduce the risk of secondary infections.

Frequent rainfall in May will be a prerequisite for an increase in the infection background of a number of fungal diseases: rusts (brown, black and yellow), septoria leaf blotch and fusariosis in wheat; downy mildews in vegetable crops and vines; blossom blight (early brown rot) and shot-hole disease in stone fruit species, and scab in pome fruit species.

More suitable conditions for carrying out plant protection spraying will occur during the second ten-day period of May, when a low probability of rainfall is forecast.

Source: NIMH