Triticale For P Removal Brad Brown University of Idaho 2008 Idaho Nutrient Management Conference

Background Surface water quality concerns related to phosphorus (P) in runoff have led to adoption of NRCS and ISDA standards that can limit dairy waste applications to amounts that provide no more P than that harvested in the cropping system.

For those limited in their manuring rates the options are: -- reduce the number of animals to accommodate the land resource -- secure additional land resources -- increased P uptake and removal from the land resource available

Single crops are limited in the P they can remove, but double cropping forages can increase the P removed and the manure loading capacity of limited land resources. Double cropped triticale and corn silage increased P uptake by 40% in one 3 yr study.

Treatments Cereals Trical 815 winter triticale Trical 2700 spring triticale Stephens winter wheat Penawawa spring wheat Hoody winter barley Seeding rates (lb/A) 100, 150, and 200

Winter Cereal Cultural Practices Planting datesHarvest dates Oct. 21, 1998May 20, 1999 Sep. 27, 1999Apr 27, 2000 Oct. 3, 2000May 12, lb N/A as urea topdressed

Question How rapidly does P uptake occur in winter triticale forages between mid stem extension and flowering in soils varying in soil P from previous manuring Triticale is harvested from late stem extension to heading depending on the triticale growth stage when corn would normally be planted.

Methods Main plots: manure and compost treatments applied 2 yrs before STP range 10 to 65 ppm in 2005, 20 to 85 ppm in Biomass measured at mid stem extension, boot, and flowering. RCB, 4 reps

Results Triticale P uptake at the boot stage ranged from 0.5 to 1.0 lb/A day depending on available P.

Nitrogen Management P based manuring, adding only the P removed with harvested forage will ultimately require added N to sustain production and P removal, especially with compost. Rate Timing

Summary Soil P did not appear to affect the forage yield response to N applied. Forage protein above 10.5 to 11% was required for maximum boot stage production and P uptake.

N Timing For grain yield Early fall preplant N is less productive than early spring top-dressed N in 2 of 3 years, in part because of excessive vegetative growth. For boot stage forage?

Summary Fall preplant applied N increased boot stage forage production and P uptake more than late winter topdressed N. Adequate N is at least as important for P uptake as it is for forage production.

Boot Stage Triticale Forage P Concentrations Without forage P analyses, triticale P removal is calculated using national NRC table values for heading stage triticale of 0.34% total P

Background Triticale P concentrations may differ appreciably in heavily manured soils enriched with P Most triticale is harvested at the boot stage or earlier Baseline P concentrations in Idaho triticale forage have not been reported or related to the NRC table values.

Objective To determine the range and mean P concentration in boot stage triticale produced in the double cropping system in relation to the NRC table values commonly used.

Methods Boot stage triticale forage surveyed 34 in in 2005 Forage samples oven dried and total P determined Soil samples also collected from sampled areas and Olsen P determined

P Concentration Mean 0.34 Range 0.18 to 0.53 Dry Forage Mg ha -1 P Removal kg ha -1

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