Biofuel co-products as livestock feed - Opportunities and challenges

230Biofuel co-products as livestock feed – Opportunities and challengesMAIN MESSAGES Sweet sorghum is a climate change-ready cropowing to its resource use efficiency and wideadaptability, in addition to apart biotic and abioticstress tolerance. In poor soils with limited inputs, sweet sorghum-basedagro-enterprises offer both foodfor humans and fodder (bagasse) for their livestock,forming a resilient mixed crop-livestocksystem. The sweet sorghum value chain offers immenseopportunities to the marginal farmers of thesemi-arid tropics as sweet sorghum offers food,feed, fodder and fuel. The centralized and decentralized systems complementeach other, and benefits percolatedown to the associated farming communities. The socio-economic, environmental and ecologicalbenefits from sweet sorghum productionand processing can be large, and need to bequantified from a systems perspective. To benefit from all the above on a large scale infarmers’ fields, well structured, sustained, supportivepolicies and R&D programmes with inclusivemarket-oriented approaches are required atboth national and international levels.TABLE 1Favourable traits of sweet sorghum cultivation as biofuel feedstock compared with popular biofuel feedstocks such assugar cane, maize and sugarbeetAs crop As ethanol source As Bagasse• • • • • • 2 2 • • • • • • • • • Notes et al. 2 2 Sources: et al et al As raw materialfor industrial products• • • per-day ethanol productivity of sweet sorghum is higherthan sugar cane (Srinivasa Rao et al., 2010, 2011), as wellas having a shorter growing period (four months) and a lowwater requirement of 8000 m 3 /ha (over two crops annually)that is only 25 percent of that required for sugar cane, whichhas a 12–16-month growing season and needs 36 000 m 3water/ha. It translates to sugar cane needing 900 m 3 waterfor producing 1 tonne of dry matter (DM) while sorghumrequires only 200 m 3 water, based on productivity of sugarcane at 40 t/ha and sorghum at 20 t/ha.Sweet sorghum’s lower cost of cultivation comparedwith sugar cane and sugarbeet, and farmer familiarity withcultivation of sorghum, aid in greater adoption of sweetsorghum.Mixed crop-livestock systems are the dominant formof agricultural production in dryland Africa and Asia.Integrating crops and livestock on the same farm helpssmall-scale farmers to diversify their sources of incomeand employment. Livestock act as a storehouse of capitaland an insurance against crop production risks, and thusprovide a coping mechanism against livelihood shocks aswell as a vital source of dietary protein. Development ofthe livestock sector provides new livelihood opportunitiesfor women, who otherwise often lack access to and controlover land-based means of production. For the majority ofsmall-scale farmers, crop residues from dual-purpose cropsconstitute 40–60 percent of total dry matter intake in theiranimal feed rations. The rest is made up from other sources.Sweet sorghum supply chainSweet sorghum feedstock supply chains have primarily twomodels of operation (Figures 1 and 2). These are consideredbelow.The centralized modelThe sweet stalk is directly supplied to the plant from thefarmers’ fields, and the juice is extracted and fermentedto ethanol and allied co-products. Its operational area isgenerally limited to a 40–50 km radius around the plantowing to high transportation costs involved in bulky raw