Effect of variety, sowing date and location on yield and nutritional characteristics of sorghum

Sorghum is a forage species important in animal nutrition with an increased potential in the upcoming difficulties in agricultural practices in regard to climate change. Therefore, this paper describes its yield and nutritional parameters depending on growing conditions simulated on two locations (humid and fertile Obora, less fertile and dry Písky), two sowing dates (29. 5. and 25. 6.), and variety (11 varieties). Fresh matter yield was determined by weighing the sample on the field immediately after harvest, Dry matter yield and nutritional content were determined in laboratory by Weende analysis from dried and homogenized samples. Nutritional parameters measured were crude fibre, fat, nitrogen and ash content. Additionally, digestibility of organic as well as dry matter was determined. No significant differences in average fresh matter yield or dry matter yield were found between the two locations and sowing dates in general. There were significant differences among varieties, the highest yields were measured in KWS Zerberus (51.57 +- 3.76 t/ha of fresh matter yield, 15.98 +- 1.34 t/ha of dry matter yield, with higher values observed on Písky). Our data suggest, that sowing date does significantly affect fat content (higher in June sowing). Other nutritional parameters were also higher in sorghum sown in June, with the exception of ash. Nutritional composition of samples did not significantly differ variety to variety, however, there were differences in digestibility of the biomass. Organic matter digestibility was 70.58-85.67%, dry matter digestibility was 73.21-86.70%, with highest digestibility in DMS 45-480. Varieties with the highest importance to farmers in the area are KWS Zerberus, KWS Tarzan and KWS Kallisto (based on dry matter yield), and Triumfo BMR, Sweet Susana and DSM 45-480 (based on digestibility). Sorghum was able to perform well even on dry sandy soil with lower fertilization, which shows the high variability and suitability of sorghum in agricultural practice.O