Effect of Dairy Manure and Anaerobically Digested Manure and Method of Application on Yield and Nitrogen Uptake of Grass

摘要

Two forms of manure: Anaerobically digested (AD) effluent (AD-Ef after liquid -solids separation post AD) and raw manure (non-AD) were land applied to grass to determine nitrogen (N) uptake and yield. The AD-Ef (2% solids) resulted from the anaerobicdigestion of dairy manure (4% solids; 80% of total input) and varying feedstocks (whey, ruminant blood, chicken DAF, egg waste; 20% of total input). The ammonia-N (NH4-N) content in the non AD manure was 37% of the total N, while 63% of the total N content in the AD-Ef was NH4-N. Manure was applied by surface broadcast (SB) or subsurface deposition (SSD) to replicated plots (n=4) in a complete randomized block design. Specific treatments were: control (no added nutrients), urea (4.9 Kg applied per plot/year at a rate of 112 Kg N/ha), non-AD + SB, non-AD SSD, AD-Ef-SB, and AD-Ef-SSD. The data shown are for the 1st year of application. The total N application rates are as follows: AD-Ef 103 514/ha of total N and 337 Kg/year/ha of NH4-N; non-AD - 479 Kg/year/ha of total N and 248 Kg of NH4-N/year/ha. There were no significant differences through 4th cutting in forage yield or N uptake due to application method or manure type. The plots with urea fertilizer had a significantly higher cumulative average forage yield/ha through 4th cutting (5555 Kg) compared to AD-Ef SB and SSD (5040 and 4546 Kg/ha, respectively) and non-AD manure SB and SSD (4973 and 5040 Kg/ha, respectively). The plots treated with urea had a significantly higher forage N uptake (225kg/ha) in the cumulative first three cumulative cuttings of the season compared to the non-AD SB and SSD, post AD-Ef SB and SSD (193,183,192 and 177 kg/ha respectively). Preliminary results of this 3 year study suggest that AD-Ef and non-AD manure support equal grass production when applied at equal amounts of total N.