Abstract

Crop residue is recognized as a potential feedstock for biofuels and a sustainable substitute for fossil energy sources. Expanding the acreage of biofuel crops, it is important to establish a crop residue retention regime to conserve soil fertility and prevent soil erosion. This paper presents simple linear and power equations between stubble biomass ratio (SBR, i. e. percentage of stubble biomass to whole plant biomass) and stubble height ratio (SHR, i. e. percentage of stubble height to maximum plant height) for a wide range of field crops of rice, wheat, oat, corn, sorghum, sunflower, canola, soybean and cotton, using data collected from 15 sites in production fields in 11 provinces across China from 2009 to 2012. Simple linear regressions for the crops were associated with highly significant coefficients of determination (R2) for all crops. Validation with independent datasets also showed high R2 values, indicating model goodness-of-fit. Mean relative error (MRE) and root mean square error (RMSE) values showed good fit for the two allometric relationships for each field crop studied. These results could be used to assess stubble mass for sustainable residue removal in bio-based energy systems.