The Fate of Nitrogen Affected By Biochar and Fertilizer Source.

Continuous improvement of nitrogen (N) use efficiency (NUE) and minimizing loss is necessary to address the environmental issues caused by fertilization in agronomic systems. The objective of this research was to determine the effectiveness of biochar amendment and fertilizer source on NUE improvement in chili (serrano) pepper production. A field micro-plot experiment was conducted. Treatments included different rates of biochar amendments (0, 10, 30, and 50 ton/ha) with synthetic (inorganic) fertilizer, and combinations of organic N fertilizer (True Organic® 4-4-2) at 50, 75, and 100% of total N supply, and a non-fertilized and no biochar treated control. Plant uptake, ammonium volatilization, and nitrous oxide production in soil profile were determined. Data from the first year showed the 30 ton/ha biochar and the 50:50 inorganic/organic N treatments resulted in the highest pepper yield, that was significantly higher than the non-fertilized control, 50 ton/ha biochar, and 100% organic-N treatments. All treatments showed higher N concentrations in pepper fruits than in the leaves and branches, but not in total mass. Neither biochar nor organic N appeared reducing NH₃ volatilization rates except a delayed peak from organic N. Nitrous oxide production in soil, however, appears to be reduced by both biochar and organic N. At the end of first crop season, N in subsurface layer (25-75 cm) was decreased the most indicating where pepper plants most likely take up N. The field results can assist in developing effective N management practices for increasing NUE and reducing total loss to the environment.