Starter and Season-Long P Effects of Dairy Manure Solids Injected Near Corn (Zea Mays L.) Rows.

Corn (Zea mays L.) often benefits from mineral P fertilizer placed near the seed at planting. There is often an abundance of P in manure on dairy farms but the possibility of injecting high-P separated manure solids near corn seed rows as a substitute for starter P fertilizer is not well known. The objective of this study was to determine the benefit of decanted manure sludge injected at various distances (5-15cm, nominally) from corn rows in terms of early and season-long effect relative to fertilizer. Field studies were conducted in a mild maritime climate in coastal British Columbia, Canada. The manure was injected at corn row spacing (15 cm depth) a few days prior to planting. Corn responded positively to injected manure at the 3-6 leaf stages with no evidence of damage to the seedlings. Response of corn to P declined with spacing distance; best growth was at 5cm spacing. At equivalent rates of P application, all performance indicators at harvest were similar for fertilizer and manure. Dairy farmers can use manure sludge collected from the bottom of storages to replace P fertilizer for corn.