Agrometeorological forecast for August

The agrotechnical time frame for sowing rapeseed starts in the third ten-day period of August. In August, for late varieties of fruit trees, the harmful activity of the last generation of fruit worms should not be underestimated. The relatively dry weather during most days of the month will be a prerequisite for an increase in mite populations. In vineyards it is necessary to monitor the occurrence and density of caterpillars of the third generation of the European grapevine moth

In August, agrometeorological conditions will be determined by temperatures and precipitation close to the climatic norms for the month.

At the beginning of August, the development of late spring crops in most parts of the country will proceed under a deepening soil moisture deficit. Exceptions will be observed in places in Northwestern Bulgaria and the Sofia field, where rainfall in July exceeded the monthly norms (Novo Selo - 84 l/m², Vratsa - 128 l/m², Montana - 88 l/m², Sofia - 111 l/m², Kyustendil - 72 l/m², Dragoman - 56 l/m²) and increased the level of moisture reserves in the 50 and 100 cm soil layer. In the western regions of the country, the forecast precipitation during the second half of the first ten-day period of August will provide moisture for the vegetation of later maize hybrids and of second crops.

In Eastern Bulgaria and in the southern regions, no precipitation is expected during the first ten-day period of August and in places the deepening drought will call into question the harvest of spring crops grown under non-irrigated conditions. In some of these regions, as a result of the scarce July rainfall - in places below 2-3 l/m² (Ruse, Shabla, Stara Zagora, Sliven, Karnobat, Burgas, Haskovo, Kardzhali), the soil moisture reserves in the 50 and 100 cm layer are completely depleted (agrometeorological station Sliven).

By mid-August, the forecast high temperatures, with maximum values up to 36-38°C, will lead to a shortening of the interphase periods in the development of late field crops. Values of this order, combined with low atmospheric humidity, will have a negative impact on flowering and fertilization in vegetable crops from late field production.

During the first ten-day period of August, earlier maize hybrids will complete their development, and medium-early hybrids will enter the milk ripeness stage. In sunflower in the Danube Plain and in the southern regions, the ripening stage will be observed. At the end of the second and the beginning of the third ten-day period in the field regions, sunflower will predominantly be at technical ripeness. During the third ten-day period, medium-late maize hybrids will enter wax ripeness. In rice, the milk ripeness stage will be observed, in soybean - the ripening stage, and in cotton - the beginning of boll opening.

The probability of precipitation, improvement of the water-physical condition of the soil in the upper layers and of the conditions for carrying out pre-sowing tillage of the areas intended for sowing with winter rapeseed, is forecast for the second half of the third ten-day period. The agrotechnical time frame for sowing rapeseed starts in the third ten-day period of August.

In August, for late varieties of fruit trees, the harmful activity of the last generation of fruit worms should not be underestimated. The relatively dry weather during most days of the month will be a prerequisite for an increase in mite populations. In vineyards it is necessary to monitor the occurrence and density of caterpillars of the third generation of the European grapevine moth. Plant protection spraying should be carried out during the cooler hours of the day with products having an appropriate pre-harvest interval, consistent with the ripening period of the crops.

Source: NIMH