Field performance and nutritive value of sweet sorghum in eastern China

• Field performance and forage quality of sweet sorghum (cv. Hunnigreen) was evaluated at different stage under rainy climatic conditions.
• Sweet sorghum (cv. Hunnigreen) has potential as an alternative crop compared to corn silage in a relatively humid environment with heavy rainfall in eastern China.
• Sweet sorghum (cv. Hunnigreen) has potential for ensiling and multiple harvests throughout the growing season because of its characteristic lateness.

The objective of this study was to estimate the feasibility of sweet sorghum (cv. Hunnigreen) as a source of green fodder and its potential as a silage crop in humid environments. One variety of sweet sorghum and two varieties of corn were compared in dry matter (DM) yield and forage quality, as measured by field performance and nutritive value. Forages were grown in a complete randomized block design with 3 replications over a two year period, harvested at the milk stage (MS) and dough stage (DS). The sweet sorghum had higher leaf area index (LAI) and plant height than both Yudan 8 and Denghai 9 corn varieties because of its characteristic lateness. Dry matter (DM) content of sweet sorghum at DS was above the minimum DM content (>247 g kg−1) needed for optimum ensiling though lower (P < 0.05) than both corn varieties. Mean DM yield of sweet sorghum (43.0 t ha−1) at DS, in two years, was higher (P < 0.05) than both corn varieties (27.0–28.8 t ha−1). Crude protein (CP) in DM and in vitro DM digestibility (IVDMD) of sweet sorghum had no significant difference compared to corn (a change of 52.1–56.6 g kg−1 DM). Neutral detergent fiber (NDF) and acid detergent fiber (ADF) of sweet sorghum was higher (P < 0.05) than that of both corn varieties except for NDF at MS in 2008. Data indicated that sweet sorghum has a higher yield than corn, with similar CP content and IVDMD. Stable nutritive value and multiple harvests of sweet sorghum offers great potential as an alternative silage crop compared to corn in the relatively humid environment of eastern China.