Corn Response to Distillers Grains As Sources of Phosphorus.

Condensed distillers solubles (CDS) is a co-product of corn ethanol production, attracting interest from some North Dakota (ND) farmers as an inexpensive, and rich alternative fertilizer source, as well as a means to recycle nutrients back to the soil. Increased storage and disposal costs of surplus CDS (or syrup) have compelled some plants to sell CDS at about $5/ton in ND. Studies were conducted in 2015 at Fairmount, and Carrington (CREC), ND, to assess yield response of dryland corn to P₂O₅ (P) fertilizer from CDS and wet distillers grains (WDG), which is also a co-product of ethanol production. Triple super phosphate (TSP), CDS, and WDG were applied and incorporated in soil at 45, 90, and 135 kg P₂O₅ ha^-1 rates, including a check (Chk). The CDS and WDG treatments received no additional fertilizer. The Chk and TSP treatments received 90 kg N ha^-1 as urea plus residual N of 120 kg. Previous crop was field pea. The experimental design was a 3x4 factorial RCBD, where P sources and P rates were factors, with four replicates. Data were analyzed by the Mixed Model in SAS. Results from Fairmount showed yield and protein responses to P rates and sources were not statistically significant (p<0.05). At CREC, yields at 135 kg P ha^-1 were significantly greater than at 0 (p<0.002) and 45 kg ha^-1 (p<0.027), across P sources. Mean yield from CDS treatment was greater than with TSP (p<0.0034) and WDG (0.0486). CDS consistently produced the highest yield at every level of P input. Yields increased in the order, TSP (8.7 T ha^-1) <WDG (8.9 T ha^-1) <CDS (9.5 T ha^-1). These first year results indicated that CDS can be a valuable source of P. Net dollar returns however, will need to be evaluated on the basis of other factors such as fertilizer prices, hauling and application costs, availability and time of application.