Abstract: [Objective] To assess the effects of different planting densities and different livestock and poultry manures as base fertilizer on agronomic traits and sugar content of feeding sweet sorghum. [Method] A two-factor randomized block designed trial using ′Liaotian′ sweet sorghum as experimental material was conducted. Five treatments including CK, normal fertilizer （NF） group, chicken manure （CM） group, pig manure （PM） group and sheep manure （SM） group were set with three levels of row spacing （45 cm, 50 cm, 55 cm） for each group. The NF group was applied 150 kg/hm² urea, the CM group, PM group and SM group were applied 15 t/hm² corresponding manures as base fertilizer respectively, and no fertilizer was applied in CK. At the harvest time, five plants of sweet sorghum were sampled from each plot to determine and compare their agronomic traits and sugar content under the conditions of different planting densities and different livestock and poultry manures as base fertilizer. [Result] When the chicken manures were used as base fertilizer, there were no significant （P>0.05） differences in agronomic traits and sugar content of sweet sorghum between different planting densities. When the sheep manures were used as base fertilizer, extremely significantly （P<0.01） higher plant height, leaf length, stem weight, stem length and sugar content were observed under the row spacing of 45 cm compared with those under the row spacing of 55 cm, and significantly （P<0.05） higher leaf area and fresh weight per plant were also observed. When the swine manures were used as base fertilizer, significantly （P<0.05） higher leaf length and chlorophyll content were observed under the row spacing of 45 cm compared with those under the row spacing of 55 cm. When the row spacing was 45 cm, the SM group had extremely significantly （P<0.01） higher plant height, leaf number and stem length compared with those of the CM group, and had significantly （P<0.05） higher leaf area compared with that of the CM group and the PM group. When the row spacing was 50 cm, the withered leaf number of the SM group was extremely significantly （P<0.01） higher than that of the other groups. When the row spacing was 55 cm, there were no significant （P>0.05） differences in plant height, leaf length, leaf number, stem diameter, stem weight, stem length, node number, fresh weight per plant and sugar content among the SM group, CM group and PM group. [Conclusion] The agronomic traits and sugar content of feeding sweet sorghum are the most significantly improved under the row spacing of 45 cm. When the sheep manures are used as base fertilizer, the feeding sweet sorghum has the best performance in agronomic traits and sugar content.

Key words: planting density, livestock and poultry manure, agronomic trait, sugar content, sweet sorghum