Abstract. Lodging is a serious problem in plant growth, especially in crops growth of the natural habitat. In order to determine the influence of lodging on the growth characters of sweet sorghum, plants grown in natural saline-alkali environment were used to investigate the fresh weight, dry weight, sugar content in the stalks and the photosynthesis index of salt tolerant crop sweet sorghum. Results showed that lodging significantly reduced the growth of sweet sorghum, the fresh weight and dry weight was only 28.3% and 22.5% of the normal plants when lodging occurred after 49 days. Lodging also reduced the stalks sugar content of sweet sorghum, the stalk sugar content of lodged plants was only 45.4% of that in the normal plants, when lodging occurred for 49 days. Lodging reduced the growth and sugar content by reducing the photosynthesis parameters of sweet sorghum grown in the saline-alkali field, thus, affected the accumulation of photosynthate. Interestingly, with the extension of the lodging time, lodging led to a decrease in photosynthetic rate of sweet sorghum mainly due to non-stomatal factors.

This study was carried out to investigate the suitable technique for increasing the stalk sugar content of two sweet sorghum cultivars (salt-tolerant cultivar Jitianza 2 and salt-sensitive cultivar Lvneng 1) in saline soils of Yellow River Delta. Stalk sugar content of sweet sorghum in saline soil was significantly increased using the following integrated cultivation technique: (1) increasing organic fertilizer level; (2) applying optimum phosphorus and potassium fertilizer; (3) surface fertilizer application; (4) cultivating salt-tolerant sweet sorghum cultivars; (5) planting with plastic mulching; (6) planting in the early of the optimum seedling time (sowing as early as possible); (7) removing tillers during seedling stage; (8) cutting spike by half-strength before flowering. Jitianza 2 had higher stalk Brix than Lvneng 1 under the same cultivation condition. Therefore, planting salt-tolerant sweet sorghum cultivars in saline soil combined with these integrated cultivation techniques can get higher stalk sugar content in Yellow River Delta of China, which was beneficial for energy alcohol production from sweet sorghum.