Effects of different mowing times on yield and quality of sweet sorghum

ObjectiveEffects of twice mowing times on yield and quality of sweet sorghum with different varieties in order to provide a theoretical basis for selecting suitable mowing time and variety of sweet sorghum in Jiangsu sweet sor-ghum planting area where twice mowing was conducted.MethodZhongketian 3 and Suketian 1(early-maturing variety), YT003 and Liaotian 1(late-maturing variety)were used as materials.The experiment was conducted by 2-factor split-plot design.Varieties were main plot,and mowing times were split plot.The first mowing was conducted after 75 d(early), 90 d(middle)and 105 d(late)of growth,the second mowing day was after 165 d of growth.One mowing was set as con-trol. Related agronomic characters,forage yield and quality of every treatment were measured at harvest time.ResultTwice harvest of varieties Zhongketian 3 and Suketian 1(early-maturing variety)treated with early or middle mowing time of the first mowing were all at heading stage or late heading stage.Plant height of all the varieties at the first mowing de-monstrated the following features:early treatmentmiddle treatment>late treatment. All the varieties treated by twice mowing showed no lodging.For every variety,average crude protein content in dry matter of the first or second mowing of twice harvest was higher than that in one harvest,while average water soluble carbohydrate,acid detergent fiber,neutral deter-gent fiber were lower than those in one harvest.Aside from average water soluble carbohydrate,main effects of fresh and dry weight,crude protein,acid detergent fiber,and neutral detergent fiber for the first mowing of twice harvest with early and middle time treatment were significantly higher than that of twice harvest with late treatment or one harvest(P<0.05). All the yield indexes of varieties Zhonketian 3 and Suketian 1 had obvious advantage over varieties Liaotian 1 and YT003.ConclusionFor sweet sorghum planting in Jiangsu Province,when applying twice mowing,early-maturing varieties would be more suitable than others.In addition,early or middle mowing time for the first mowing should be conducted.