High for the season soil moisture reserves in August

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

At the beginning of August, the development of agricultural crops will proceed under unusually high for the season soil moisture reserves at 50 and 100 cm. In some of the field areas, for the spring crops (maize, sunflower), they are over 90% of field capacity (FC), as a consequence of the significant July precipitation, which in many places in the country reached and exceeded twice the monthly norm (Vratsa - 138 l/m², Montana - 117 l/m², Lom - 134 l/m², Knezha - 150 l/m², Lovech – 138 l/m², Veliko Tarnovo – 159 l/m², Shumen – 143 l/m², Ruse – 120 l/m², Sofia - 177 l/m², Plovdiv – 127 l/m², Kazanlak – 129 l/m², Kardzhali – 120 l/m², Elhovo and Karnobat – 134 l/m²).

During most days of the first ten-day period, agrometeorological conditions will remain unstable, with frequent showers that will delay the completion of the wheat harvest and will further deteriorate the quality of the unharvested grain crop. The forecast wet weather will increase the risk of spread and development of grey mould on grapes, especially in vineyards affected by the July hailstorms. Conditions during this period will remain optimal for the development of late brown rot on fruit trees and for downy mildew on vegetable crops.

During the first ten-day period, early maize hybrids will complete their development. In medium-early hybrids, the milk ripeness stage will be observed. In sunflower, seed filling will be in progress. Some of the stands in the Danubian Plain and in the southeastern regions will enter the beginning of the ripening stage.

During the second ten-day period, a substantial increase in temperatures and an acceleration of the development rates of late agricultural crops are expected. The forecast maximum temperatures, in places up to 36-37°C, will have a short-term negative impact on flowering and fertilization in vegetable crops from late field production. At the end of the second and the beginning of the third ten-day period, mass technological ripeness in sunflower will be observed.

During the third ten-day period, medium-late maize hybrids will enter the wax ripeness stage. In late hybrids, grain filling and the milk ripeness stage will be in progress. In soybean, the ripening stage will be observed, and in cotton – boll opening. During the ten-day period, the milk ripeness stage will predominate in rice.

In August, more suitable conditions for conducting plant protection spraying against diseases and pests will occur at the beginning of the month and during most days of the second ten-day period.

During the second ten-day period, an improvement in conditions is expected for deep ploughing and for pre-sowing tillage of areas intended for sowing with winter oilseed rape. The agrotechnical time frame for sowing oilseed rape begins in the third ten-day period of August.

Source: NIMH