title: Carbon consequences and agricultural implications of growing biofuel crops on marginal agricultural lands in China.
abstract: Using marginal agricultural lands to grow energy crops for biofuel feedstocks is a promising option to meet the biofuel needs in populous China without causing further food shortages or environmental problems. Here we quantify the effects of growing switchgrass and Miscanthus on Chinese marginal agricultural lands on biomass production and carbon emissions with a global-scale biogeochemical model. We find that the national net primary production (NPP) of these two biofuel crops are 622 and 1546 g C m(-2) yr(-1), respectively, whereas the NPP of food crops is about 600 g C m(-2) yr(-1) in China. The net carbon sink over the 47 Mha of marginal agricultural lands across China is 2.1 Tg C yr(-1) for switchgrass and 5.0 Tg C yr(-1) for Miscanthus. Soil organic carbon is estimated to be 10 kg C m(-2) in both biofuel ecosystems, which is equal to the soil carbon levels of grasslands in China. In order to reach the goal of 12.5 billion liters of bioethanol in 2020 using crop biomass as biofuel feedstocks, 7.9-8.0 Mha corn grain, 4.3-6.1 Mha switchgrass, or 1.4-2.0 Mha Miscanthus will be needed. Miscanthus has tremendous potential to meet future biofuel needs, and to benefit CO(2) mitigation in China.
authors.affiliation: Department of Earth & Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907, United States. qin9@purdue.edu
authors.forename: Zhangcai
authors.initials: Z
authors.lastname: Qin
authors.forename: Qianlai
authors.initials: Q
authors.lastname: Zhuang
authors.forename: Xudong
authors.initials: X
authors.lastname: Zhu
authors.forename: Ximing
authors.initials: X
authors.lastname: Cai
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000383:Agriculture / Q000191:economics / Q000379:methods / Q000706:statistics & numerical data*; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control / Q000706:statistics & numerical data; D056804:Biofuels / Q000032:analysis* / Q000706:statistics & numerical data; D002245:Carbon Dioxide / Q000032:analysis; D058572:Carbon Footprint / Q000191:economics / Q000706:statistics & numerical data*; D002681:China; D018556:Crops, Agricultural / Q000254:growth & development*; D004784:Environmental Monitoring; D058735:Environmental Policy; D005523:Food Supply
chemical_list: D000393:Air Pollutants; D056804:Biofuels; D002245:Carbon Dioxide