Spatial distribution of agricultural residue from rice for potential biofuel production in China

In China, agricultural residues (particularly from rice) are widely used for energy and other applications, albeit on a localized scale and often at poor rates of efficiency. If some portion of this biomass were to be reallocated and transported to central biomass energy facilities, an initial component of the design process would be to gain an understanding of the spatial distribution of biomass production. In this paper, we present a method that utilizes China-wide data sets of net primary production (NPP) from the moderate-resolution imaging spectrometer (MODIS) and detailed land cover maps produced from Landsat-enhanced thematic mapper plus (ETM+) data to calculate the spatial distribution of rice straw for the period 2000-2004. Through a comparison with census statistics, we show that remote measures of rice straw can reasonably predict census results at the provincial scale. Remote sensing results have the added benefits of being a quick and inexpensive solution for providing spatially detailed information. Therefore, these data can be used for applications such as the spatial optimization of energy production infrastructure. In an error analysis including climate and land use variables, we found that data on sown rice area is the largest source of error. Therefore, the most important improvement to this method would be more accurate and more frequently updated maps of agricultural land use.