Assessment of the fertilizer potential of distillers' grains from wheat-based ethanol production

Abstract

A surplus of distillers’ grain resulting from rapid expansion in biofuel production has led to interest in finding alternative uses for this co-product apart from its traditional use as an animal feed. Land application to agricultural soil in order to recycle the nutrients is one potential use. In this study we evaluated the effect of a single application of wet wheat distillers’ grain (WDG) on crop yield and nitrogen and phosphorus uptake in a three-year canola-wheat-canola rotation in southern Saskatchewan. The experimental treatments included a single application of WDG at a rate of 100 kg N ha-1 in comparison to urea applied at the same rate of N along with an unfertilized control. In the first year, WDG produced a canola yield of 1266 kg ha-1 that was significantly higher than the urea treatment. The WDG treatment resulted in higher plant N uptake that was 59 % higher than the control, but was 20 % less than that observed in the urea treatment, indicating that only a portion of the applied N in the WDG was available for recovery. Higher yield of WDG is attributed to a benefit of other nutrients in addition to N. Both WDG and urea treatments had a significant effect on plant P uptake in the first year. The residual effect of WDG addition on crop parameters in the second and third years was mainly limited to enhancement of plant P uptake. Overall, the WDG applied at the same rate of N was as effective in increasing crop yield as urea.