Ecological Assessment of Conditions for Sorghum ( Sorghum bicolor ) Cultivation Based on the Determination of its Yield Plasticity

Abstract

In Ukraine, sorghum is grown in an area of 41000−49000 ha, with the yield ranging over years from 0.99 t/ha (2001) to 4.63 t/ha (2018). Such differences in productivity may be explained by the fact that, in recent decades, the value of degree-days in the Steppe zone increased from 3145°C (1990) to 3550°C (2019), and in the Forest Steppe zone by 445°C. At the same time, the current annual precipitation in Ukraine is 578 mm, while sustainable farming requires 700 mm. In Steppe, which is a traditional sorghum cultivation zone, the change in climatic conditions led to insufficient soil moisture, with weather conditions influencing the formation of sorghum grain yield. The assessment of the stability and plasticity of the sorghum yield allows us to conclude that cultivation of this crop will not be effective without irrigation, adjustment of the cultivation technology or introduction of the varieties adapted to drought and high temperature. On the contrary, in Forest Steppe, conditions for obtaining high yields of sorghum improved in recent decades. Thus, in Vinnytsia region, favorable conditions formed in the years 2011−2020, in Kyiv region 2001−2005 and 2011−2015, and Poltava and Cherkasy regions 2006−2020. However, in Vinnytsia region, in the years 2001−2005, and in Kyiv region 2006−2010, low yield plasticity was caused by the negative impact of the extreme drought. Consequently, to reach high crop productivity and stable grain yield, it is necessary to introduce an ecologically sound sown area structure and use varieties of different genetic and geographical origins that are more resistant to the impact of adverse environment.

Keywords

• yield
• sorghum
• sown area
• croppage