The effectiveness of retardants moddus and messidor in the cultivation of spring barley on different nutrient status

The results of field experiments on the effectiveness of the use of retardants Moddus and Messidor in the cultivation of spring barley at different levels of mineral nutrition are presented. The shortening of the second internode of barley plants by 3.3-24.1% and the increase in its thickness by 1.43.7% were established when using retardants Moddus and Messidor in different doses on a high nutrient content. The data obtained indicates positive effect of retardants on increasing the resistance of barley stems to unfavorable factors (rain and wind), which is confirmed by the results of assessing the degree of lodging. It was found out that the use of retardants on natural nutrient content in a dry growing season leads to the significant decrease in yields (from 0.22 to 0.94 t/ha). In slightly arid and excessively humid conditions of the growing season, the use of retardants on medium nutrient content provides the significant increase of the yield from 0.22 to 0.53 t/ha, on high nutrient content from 0.21 to 0.52 t/ha. In average, over three years of research, the highest yield of barley was obtained on high nutrient content when crops were treated with Messidor at a dose of 1.0 l/ha, Moddus at a dose of 0.4 l/ha. The best economic indicators were established when feed barley was cultivated on medium nutrient content (N 15 P 39 K 39 + pre-seeding application of N 68 ) using retardants Moddus at a dose of 0.2 l/ha, Messidor at a dose of 0.5 l/ha.