Information and regulatory role of solar radiation in the twilight in development and productivity of spring grain crops
Based on theoretical analysis of the available experimental data a big role of the physiologically active diffuse solar radiation during civil twilight in the reactions of the transition to the formation of the productive organs of spring crops is shown. Introduced is the concept of the physiologically active length of the day (FADD) taking into account the civil twilight. The influence of FADD on flowering response and the reasons of the plants development rate reduction with the FADD reduction are discussed. The possibility for agrometeorologists to use this information for the development of more complex physical and mathematical models of the production process of spring grain crops is accentuated.