Agrometeorological forecast for April

During the first ten-day period of April, agrometeorological conditions will be determined by unstable weather with frequent precipitation, which will improve moisture reserves in the upper soil layers and the conditions for vegetation of the autumn-sown crops and the sown spring crops. As a result of below-normal precipitation in March, in many parts of the country the soil moisture reserves in the 50 cm and 100 cm layer are unsatisfactory for the season. The lowest levels, below 70-75% of field capacity, are the moisture reserves in the 50 cm layer in winter cereal crops in the northwestern and southeastern regions (agrometeorological stations Knezha, Pavlikeni, Chirpan, Sliven, D. Chiflik).

During the first ten-day period, the development of winter cereal crops will proceed at a moderate rate at temperatures close to the climatic norms. During this period, the tillering stage in wheat will be occurring on a mass scale. In a small part of the stands sown within the agrotechnical time frame, in certain locations in the Danube Plain, a transition to the stem elongation stage will also be observed.

A substantial improvement of thermal conditions and an acceleration of the vegetation processes in agricultural crops is expected during the second and the first half of the third ten-day period. The forecast precipitation in the second half of April will be of significant importance for the normal progress of the initial stages of vegetation in sunflower. This precipitation will have a beneficial effect on wheat and barley, in which the stem elongation stage will be occurring on a mass scale, and at the end of the month, in some places, the beginning of the heading stage will also be observed. During these stages, the water requirements of winter cereal crops for soil moisture increase sharply.

In April, the forecast minimum temperatures, down to minus 2°C, if they persist for a longer period, will be critical for the blossoms and young fruit set of fruit trees (almond, apricot, peach, cherry), which will be in the flowering and fruit setting stages. More suitable conditions for carrying out plant protection spraying against some economically important diseases – blossom blight (early brown rot), shot-hole disease, scab on pome fruit species, etc. – will occur during the first half of the second and third ten-day periods. 

At the beginning of the third ten-day period, in the field regions, the soil temperature in the 10 cm layer will reach values suitable for sowing maize for grain, and by the end of the month – also for thermophilic spring crops (cotton, beans, peanuts, watermelons, melons, etc.).

During the second half of April, wheat stands should be monitored for the occurrence and harmful activity of certain pests: the cereal leaf beetle, wheat thrips, sunn pest, and, when pest density exceeds the economic threshold of harmfulness, timely treatment is necessary.

Source: NIMH