Kenaf forage yield and quality under varying water availability

A broadleaf forage crop grown in rotation with winter wheat (Triticum aestivum L.) would diversify dryland crop rotations in the central Great Plains. Kenaf (Hibiscus cannabinus L.) provides good quality livestock forage, but yield and quality have not been evaluated under varying water availability conditions. This study determined kenaf soil water extraction, plant height, regrowth following cutting, dry matter (DM) yield, and forage quality responses to varying water availability. Kenaf was planted on a Weld silt loam (fine, smectitic, mesic Aridic Argiustolls) under a line-source gradient irrigation system. Water conditions ranged from rainfed to full evapotranspiration replacement. Kenaf was harvested in early August and then again in October. Dry matter yield increased linearly with increases in available water and water use, with about 2000 kg ha(-1) DM yield produced with 274-mm water use increasing to 6000 kg ha(-1) with 507-mm water use. Crude protein (163 to 279 g kg(-1)) decreased with increasing water use. Neutral detergent fiber (229 to 478 g kg(-1)) and acid detergent fiber (168 to 314 g kg(-1)) increased with increasing water use. Total digestible nutrients (656 to 840 g kg(-1)) and relative feed value (range 130 to 308) decreased with increasing water use. For a given amount of water use, kenaf DM yield was lower than corn (Zea mays L.) silage, but kenaf crude protein production was higher than corn silage (73-215%). Kenaf appears to be a high quality livestock forage that has potential as both an irrigated or dryland crop in the central Great Plains.