Nutrient Availability and Biomass Yield in Soils Receiving Manure from Cattle Fed DDGS Diet.

The steady rise in bio-ethanol production has led to increased use of dried distiller grain with solubles (DDGS) in feedlot cattle diets. Feeding of cattle with DDGS diet increases the excretion of nitrogen (N) and phosphorus (P) and the fraction of water soluble P in manure. Repeated application of manure N and P beyond crop demand could result in the loss of these nutrients to the aquatic environment. In this greenhouse experiment, we investigated the effects of repeated application of feedlot manure from cattle fed a DDGS diet (DM) on canola (Brassica rapa L.) and triticale (Triticosecale wittmack) yield, nutrient uptake, and changes in available N and P in two contrasting chernozemic soils. The treatments included DM, DM + construction waste, and regular manure from a typical finishing diet. Five growth cycles of canola and triticale were cultivated in pots containing 1.5 kg soil treated with Nitrapyrin and mixed with 0.06 kg of the organic amendments. The soils were seeded the same day (day 0) the amendments were applied. The soils were leached with deionized water 15 days after manure application. Results on nutrient utilization and N use efficiency will be presented. Information from this study will improve our understanding of nutrient recovery by crops grown on soils receiving DM. Managing a balance between crop nutrient demand and the amount of manure applied is key in preventing further build-up of manure nutrients in soil and the eventual loss to the environment.