Site suitability analysis incorporating disease prediction in castor (Ricinus communis L.) production

Castor (Ricinus communis L.) is an important industrial crop used in the production of nylon, cosmetics, and many industrial lubricants. Currently, castor production in the USA has nearly ceased for > 45 years, resulting in vast imports of castor oil to meet US demands. Renewed interest in this crop, especially the possibility of its use as a biolubricant, has increased the desire to learn more about where it can be produced. This study evaluated possible locations for castor production through site suitability analysis. This analysis determined potential sites for castor production by evaluating geospatial climatic, soils/geophysical, and disease data, the major drivers of castor growth and yields. The site suitability analysis determined that 12% of the contiguous USA is highly suitable for castor production. The state of Illinois has the highest percentage of arable land highly suitable for castor production (56%/8 million ha). However, due to its large size, Texas has the most land area highly suitable for castor production (similar to 15 million ha). Validation of the site suitability analysis was obtained through ground-truthed data obtained from recent environmental studies testing various castor genotypes. For the southern USA (< 40 degrees N latitude), the regression analysis interested in site suitability point data versus performance (oil yield) at known growing sites resulted in a significant result (R-2 = 0.46, p < 0.01). Geospatial averaging site suitability values for 1-km buffer of those growing sites further improved regression analysis (R-2 = 0.57, p < 0.01). T he findings of this study provide a method to perform site suitability for novel crops such as castor using data associated with agronomic and disease characteristics. Moreover, the analysis provides suggestion that castor could easily be reintroduced to US agricultural practices.