Injected Slurry Sludge Provides Starter P for Silage Corn.

In livestock intensive areas there is often a surplus of manure and it is important to efficiently utilize manure nutrients. Buildup of P in soils is a particular problem due to the high P:N ratio in manure.  This study investigated growth response of corn to starter P supplied as injected separated slurry sludge in close proximity to corn rows. The field trials were conducted over 3 years under moderate maritime conditions in coastal BC. The sludge was injected at approximately 30 kg P ha^-1 at 75-cm spacing and 12 cm depth. Corn was planted at 0, 5, 10 and 15 cm from the corn rows several days after injection. Comparing roots on both sides of the corn rows showed that the slurry sludge did not affect root growth or colonization by arbuscular mycorrhizae. There was generally a positive correlation between response to manure P at the 3 and 6 leaf stages and proximity of the injection furrow to the corn row. The application of sludge improved crop maturity. The results suggest that injected slurry can be used as an effective source of starter P for corn. Additional research is needed to assess possible deleterious effects of the sludge under a wider range of conditions.