Precision Placement of Dairy Slurry to Supply N and P for Silage Corn.

Corn benefits from starter fertilizer even when grown on high fertility soils receiving manure. Starter P can be supplied by liquid manure or slurry sludge if precision placed near corn rows. However injection of manure can cause increased risk of N2 O emission and nitrate leaching, The study was conducted over 4 years in a moist maritime climate in south coastal BC, Canada, Manure was injected to 15 cm depth at 70 cm spacing a a few days corn was precision planted 0 to 10 cm from the corn rows. Corn was harvested fo silage and treatments were repeated for 4 years. Corn yields and N uptake with injected manure was superior to broadcast manure and approached commercial fertilizer but at somewhat higher N application rates. There was relatively little difference between manure and fertilizer for N leaching which persisted overwinter but N2O emissions were much greater for injected then broadcast manure or fertilizer however application of nitrification inhibitor DCD mitigated the emission peak after manure application.