The sustainability of biofuels depends on considering the environmental consequences of using water and land resources for bioenergy production. The objective of this study was to assess the potential for biofuel crop expansion by combining water footprint, water availability, and land availability in the last agricultural frontier region of Brazil using the Corrente Basin as a case study. Results show that the water footprint (ratio of water consumption to biomass or energy production) of sugarcane is low (114–190 m³ Mg⁻¹) reflecting high water consumption (∼9000 m³ ha⁻¹) divided by high crop yield (∼50–80 Mg ha⁻¹), including millable stalks. However, water consumption for sugarcane grown in this area (9370 m³ ha⁻¹) exceeds water availability in much of the basin (90th percentile of streamflow), which limits sugarcane expansion. In contrast, the water footprint of soybeans (900–2600 m³ Mg⁻¹) is 8–14 times higher than that of sugarcane, reflecting much lower water consumption (∼1500–3800 m³ Mg⁻¹) and even lower crop yield (0.7–4.3 Mg ha⁻¹), limited to grains, relative to sugarcane. The low water consumption of soybeans allows expansion under rainfed agriculture during the wet 1st harvest season over 22% of the region and under irrigation during the dry 2nd harvest season over 13% of the region, without the need for deforestation of the Cerrado biome. This soybean expansion represents ∼20 × 10⁶ GJ of energy supply per year, ∼4 times current production. Surface water availability for irrigation extends into the dry season because of substantial groundwater discharge to streams during the dry season. Irrigation increases biofuel crop yield of sugarcane and soybeans, reducing land area required to produce an equivalent amount of biomass by 2 to 4 times relative to rainfed management. Therefore, water can be traded for land by expanding irrigated biofuel production, conserving more native Cerrado vegetation. Considering water and land requirements relative to availability for bioenergy crops provides data on potential increases in bioenergy production while minimizing clearing of native vegetation in the Brazilian agricultural frontier.

生物燃料的可持续性取决于考虑将水和土地资源用于生物能源生产的环境后果。这项研究的目的是结合科伦特盆地为案例，通过结合巴西最后一个农业边境地区的水足迹，水供应和土地供应来评估生物燃料作物扩大的潜力。结果表明，甘蔗的水足迹（水消耗与生物质或能源生产的比率）低（114–190 m ³  Mg ^-1），反映了高水消耗（〜9000 m ³  ha ^-1）除以高作物产量（ 〜50–80 Mg公顷^-1），包括可铣削的秸秆。但是，在该地区种植的甘蔗的用水量（9370 m ³  ha ^-1）超过了盆地大部分地区的可用水量（流量的90％），这限制了甘蔗的扩张。相比之下，大豆的水足迹（900–2600 m ³  Mg ^-1）是甘蔗的8–14倍，反映出更低的水消耗量（〜1500–3800 m ³  Mg ^-1），甚至农作物产量更低（0.7–4.3 Mg公顷^-1），仅限于谷物（相对于甘蔗）。大豆的低耗水量使该地区22％的潮湿第一收获季节在雨养农业下扩张，而该地区13％的干旱第二收获季节在灌溉农业下扩张，而无需砍伐塞拉多生物群落。大豆膨胀量约为20×10 ⁶ 每年能源供应的GJ，约为当前产量的4倍。灌溉期间地表水的可利用量一直持续到干旱季节，因为在干旱季节大量的地下水排放到溪流中。灌溉增加了甘蔗和大豆的生物燃料作物产量，使生产等量生物量所需的土地面积比雨养管理减少了2至4倍。因此，可以通过扩大灌溉生物燃料的生产来水交换土地，以保护更多的塞拉多原生植被。考虑到相对于生物能源作物可获得性的水和土地需求，可提供有关生物能源产量潜在增长的数据，同时最大程度地减少巴西农业边界的原生植被清除。