Nitrogen utilization and capture by winter triticale

Winter triticale (XTriticosecale Wittmack) has the potential to reduce nitrate nitrogen (NO₃N) loss from Iowa cropping systems if grown as a cover crop, for grazing or forage production, or as a grain crop. This research was conducted to quantify N uptake of triticale and to determine the amount of N fertilizer needed to achieve maximum triticale forage and grain yield following either corn (Zea mays L.) or soybean (Glycine max (L.) Merr.). Triticale was planted near Ames and Lewis, Iowa in 2003 and 2004. Four N fertilization rates (0, 33, 66, 99 kg N ha⁻¹) were evaluated in a randomized complete block design. Triticale grain yield near Ames showed a significant response to the first increment of N (33 kg ha⁻¹), but no additional response to 66 or 99 kg N ha⁻¹. For triticale following corn at Ames, N concentration and total dry matter N increased with higher N rates. Dry matter accumulation increased with the first 33 kg N ha⁻¹, but there was little further dry matter produced from N rates greater than 33 kg ha⁻¹. Overall, for both locations, and prior crops, dry matter accumulation increased steadily between spring regrowth and maturity while N concentration declined. Nitrogen uptake, however, was relatively flat for each location and previous crop. Ames triticale following soybean captured nitrate at N rate 0 kg N ha⁻¹ but there was a substantial amount of nitrate that was lost at 33, 66, and 99 kg N ha⁻¹, but triticale following Ames and Lewis corn and Lewis soybean was able to capture a significant amount of soil nitrate. This research suggests that 33 kg N ha⁻¹ is sufficient for triticale growth in Iowa following corn or soybean to have effective triticale N response and grain yield