Time Determination of Conducting Senication of Rice Crops Taking Into Account the Sum of Effective Temperatures

Resumo

Analysis of the moisture dynamics of leaves, stems, and panicles, as well as caryopsis filling, after treating rice crops with senicants showed that senication (if necessary) should be carried out for acceleration of ripening and biosynthesis of organic substances when the sum of temperatures above 15°C has reached 700–750°C. When carried out during this period, it does not cause premature dehydration of leaves and panicles and does not slow the caryopsis filling, which causes caryopsis moisture to reach 25% 3–10 days earlier and an increase of 3.5–10% by weight of panicles and rice yield by 0.30–0.39 t/ha in comparison with the control. It is viable to use aqueous solutions of ammonium nitrate at the rate of 15 kg/ha or carbamideammonium mixture CAM-32 diluted with water in a ratio of 1: 5 modified by adding 400 g/ha of manganese with a rate of working solution of 200–250 L/ha for this purpose.