Productivity, profitability, and energetics: A multi-criteria assessment of farmers' tillage and crop establishment options for maize in intensively cultivated environments of South Asia

摘要

Responding to increasing demand from poultry and fish feed industries, maize area is rapidly expanding in South Asia. Current tillage and crop establishment (TCE) practices are however associated with high levels of input use, including direct and indirect forms of energy. In Bangladesh, policy makers emphasize the need to reduce the USD 1.4 billion year(-1) agricultural energy subsidy. Bangladeshi farmers cultivate maize during the winter rabi season, when yield potential is high. But when poorly managed, farmers' investments in TCE practices may erode farm-level profitability, while inefficiently utilizing energy. Resource-conserving TCE options may however provide an alternative for maintaining or raising yields, while increasing farmers' income and reducing energy use. We present a multi-criteria assessment of the productivity, profitability and energetics of alternative TCE options, including zero (ZT), reduced (RT), and strip tillage (ST), in addition to fresh (FBs) and permanent bed planting (PBs), contrasted with conventional tillage (Cl') in Bangladesh's main maize producing agro-ecological zones (AEZs). Trials were conducted in 184 farmers' fields in Bangladesh's northwestern districts with coarse-textured soils (Rangpur and Rajshahi in AEZs 3 and 1 I, respectively) and in one eastern district with fine-textured soils (Comilla in AEZ 19). Trials spanned the 2009-2010 to 2012-2013 rabi seasons. Significant TCE effects on grain yield were observed in AEZs 3 and 11, but not in AEZ 19. Compared to CT, grain yields under FBs, PBs and ST were significantly higher in AEZ 3, and also under FBs and PBs in AEZ 11. Production cost was 7.8% lower, while net profit and benefit-to-cost ratios for the alternative TCE options were 13.7 and 20% greater than CT, although data were inconsistent in AEZ 19. Across AEZs, total energy inputs were significantly higher for CT (30.3.5 x 10(3) to 33.8 x10(3) MJ ha(-1)) compared to alternative options (28.3 x10(3) to 32.7 x 10(3) MJ ha(-1)). Permanent beds required the lowest diesel energy compared to CT. Similarly, energy use efficiency (EUE) was significantly higher for PBs and ST compared to CT in AEZ 3 (7.17-8.08 MJ MJ(-1)) and for PBs and FBs in AEZ 11 (8.55-10.26 MJ MJ(-1)). Among all options, PBs, FBs and ST provided greater benefits in terms of increased yield and profits, increased EUE, and reduced economic risks in AEZs 3 and 11, but less so in AEZ 19. Poor performance in the latter region was due mainly to poorly-drained low- to medium-low land types that delayed maize planting and impeded optimal establishment. Further efforts are needed to untangle the determinants of spatially variable performance to refine recommendation domains for TCE options for maize in South Asia. (C) 2015 Elsevier B.V. All rights reserved.