Biomass, extracted liquid yields, sugar content or seed yields of biofuel feedstocks as affected by fertilizer

Harvesting products from plants for conversion into renewable resources is increasing in importance. Determination of nutrition requirements for the applicable crops is necessary, especially in regions where the biofuel feedstock crops have not been historically grown. Sunflower (Helianthus annuus L.), two hybrids and one variety; sweet and grain (milo) sorghums (both Sorghum bicolor L.), one variety each, and sweet corn (Zea mays var. rugosa Bonaf.), four cultivars, were provided the recommended and twice the recommended rate of fertilizer. Biomass, expressed liquid volumes and sugar contents of sweet sorghum and sweet corn were determined. Grain yields of milo and sunflower and oil content of sunflower were determined. Sweet corn stalk sugar levels were below what is expected from field corn (maize), and were not affected by fertilizer rate. Sweet sorghum biomass and sugar content were within expected ranges and not affected by fertilizer rate. Milo grain yields were higher with increased fertilizer. Seed yield in Sunflower, which was below expected levels, was inconsistently affected by fertilizer rate, years or varieties. Overall crops year and cultivar/variety had more effect on results than did fertilizer. There does not appear to be a reason to provide fertilizer above recommended rates in production of these crops.