Nitrogen Availability from Granulated Fortified Poultry Litter Fertilizers

摘要

Poultry litter (PL) and municipal biosolids (BS) are valuable fertilizer sources due to significant nutrient concentrations. However, if applied to satisfy soil test P recommendations, low N/P ratios coupled with low total N availability provide inadequate fertilization. Nitrogen fortification is needed to increase PL and BS utility as agronomic and horticultural fertilizers. The objective of this study was to model N release characteristics from N-fortified PL granular fertilizers containing additives and to compare these sources to fresh PL, BS, and standard fertilizers. A 2 x 2 x 3 x 8 factorial arrangement of PL granules with and without BS, with and without a nitrification inhibitor [dicyandiamide (DCD)] and bound with lignosulfonate (LS), urea formaldehyde, or water was tested in a 112-d non-leached aerobic incubation study. The investigation was conducted on a silt loam soil in a randomized complete block design. Extraction procedures for inorganic N were conducted at 0, 3, 7, 14, 28, 56, 84, and 112 d. Granular product mineralization patterns were also compared with fresh PL, ground PL, BS, Milorganite, DCD, and urea treatments. Averaged over the entire incubation period, granulated products had apparent net N mineralization of 71.5% while urea, BS, and PL averaged 80.5, 16.8, and 36.7%, respectively. Granules containing DCD had 6.7% less apparent net N mineralization and suppressed nitrification in granular treatments until 56 d after fertilizer application. Binding agent and BS additions had no statistical impact on NH4-N or NO3-N soil concentrations. Nitrogen-fortified PL granules may improve N efficiency over fresh PL and BS due to more N availability and less potential environmental N losses over a growing season