Assessing the Mineral Fertiliser Nitrogen Replacement Value of Poultry Manure in Spring Barley Cropping.

There were almost 11 million poultry in Ireland in 2010 (CSO, 2010); a significant source of manure. The mineral fertiliser replacement value (MFRV) of manure impacts the economics of transport and determines the mineral fertiliser balancing requirement. In cereals understanding the N MFRV is particularly important to avoid lodging, yield loss or to produce grain with protein meeting requirements. A well-drained experimental site located at 52°48’51.16” N 6°8’39.56”W was used with four replicates per treatment. Ploughing, treatment application and sowing were completed on 31 March 2016. P, K, Mg & S was applied to all plots. Poultry manure was applied at six N rates. The mineral fertiliser treatment N was calcium ammonium nitrate (CAN) (50 to 250 kg N ha^-1 in 50 kg increments). Crop yield, grain protein and total crop N recovery were measured at harvest. The poultry manure was from a modern poultry house with manure drying facilities. The manure dry matter (D.M.) was 88.1% and manure contained 38.1, 11.3 and 22.9 kg of N, P and K, respectively per tonne D.M. Spring barley grain yields responded strongly to mineral fertiliser N and to manure application reaching maximum yields of 10.2 and 10.3 t/ha, respectively. In comparison the control plot yielded 6.0 t/ha. The N in poultry manure is currently assumed to be 50% available in the season of application. Spring barley plant and grain samples are currently being processed and N uptake measured. This data will be used to evaluate the N MFRV of poultry manure in this trial and will be presented. Poultry manure, particularly dried manure, is a concentrated nutrient source relative to other manures/slurries. It’s relatively high nutrient concentration lends itself to transport over longer distances than liquid slurries which is fortunate as the poultry industry in many regions including Ireland is quite concentrated.