Water efficiency and salt-tolerance
Sorghums have a high water efficiency, requiring less total water to reach their production potential than maize. In environments where water is limited due to drought or declining aquifers, and where it is necessary to conserve or reallocate available water, forage sorghums are promoted as a substitute for more water-consuming crops, particularly forage maize. Sorghums will be an extremely valuable forage wherever water becomes a scarce and precious resource due to global climate change (Brouk et al., 2011; Emile et al., 2006; Contreras-Govea et al., 2010). The combination of drought-tolerance and salt-tolerance makes sorghum a very interesting feed resource under arid and semi-arid conditions in saline lands (Al-Khalasi et al., 2010; Fahmy et al., 2010; Khanum et al., 2010).
Toxic soil reclamation
Sorghum is tolerant of many pollutants and it thrives in toxic soils that kill most plants. Sorghum can take up excess soil N due to its penetrating root system and this ability has been useful to reclaim fallow lands where soil N up to 400 kg/ha has been recorded. Sorghum also thrives on salty irrigated soils: it restores the porosity of the soil making it possible to grow a high yielding wheat crop in one season (NRC, 1996).
Cover crop and soil improver
Sorghum can be used as a cover crop during the fall and winter: sown during the fall, it covers more than 60% of the soil surface before winter and protects it from wind erosion. It also helps sparing more water than other cover crops because it dies quickly after the first frost and does not withdraw water from the soil. After harvest, ploughing down the stubbles can improve the organic status of the soil and limit erosion (UC SAREP, 2006; NRC, 1996).
Weed and pest control
Detrimental effects on broad-leaf weeds last beyond the life of the sorghum. This could be due to the release of phenolics and cyanogenics by the roots (NRC, 1996).
Crop support
Dead stalks of sorghum grain can provide support to climbing legumes several months after the grain is harvested (NRC, 1996).
Regeneration of native pastures
In Queensland, Australia, sweet sorghum was one of the species successfully used in attempts to revegetate severely degraded bluegrass pastures (Dichanthium sericeum). It was added to the mixture to give extra competition to volunteer weeds, and as a safety measure to ensure cattle had fodder in the paddock. It provided fodder four to five months after sowing and cattle preferred it to the other sown species (Lambert et al., 1999).