Nitrogen Timing for Boot Stage Triticale Forage Yield and Phosphorus Removal.

Winter triticale is an important winter forage for irrigated double crop systems designed to maximize forage and phosphorus (P) removal from compost P enriched soils. Whereas nitrogen timing for maximum small grain seed production has been determined for this irrigated system, the appropriate timing for boot stage forage production and P removal has not.  Nitrogen rates (0, 112, and 224 lb urea N/ha) were evaluated at two timings (preplant incorporated or late winter top-dressed) in two years on soil differing in compost P enrichment at the University of Idaho Parma R & E Center.  Unlike small grain seed production where winter topdressed urea N is generally more effective than preplant incorporated urea, preplant incorporated urea was the most effective timing for maximizing boot stage triticale forage biomass production and P removal.    Forage P uptake from P enriched soil was greater for the highest N rate in both years regardless of whether forage biomass was the highest.  Uptake of P appears to be more sensitive than forage yield to available N in compost P enriched soils.