Organic nitrogen fertilizer sources for field production of flue-cured tobacco (Nicotiana tabacum L.)

Despite rapid expansion of organic tobacco (Nicotiana tabacum L.) production in the US, limited research has been conducted comparing the numerous organic fertilizer sources. Organic flue-cured tobacco traditionally relies on feather meal as the organic N fertility source, as it is readily available, but there is limited information on alternative organic N fertilizers. The objective of this research was to investigate seven different organic fertilizer sources to determine their effect on the growth and development of flue-cured tobacco. From 2018 to 2019, field sites were established at four locations in North Carolina. Fertilizer treatments included sodium nitrate, composted layer manure, feather meal, corn gluten, soy protein, blood meal, and seabird guano. Both years, these organic N treatments were banded at sidedress (10 d after transplanting) at a rate of 78 kg total N ha(-1). Sodium nitrate resulted in higher foliar nitrate-N concentration than composted layer manure at layby and higher cured leaf yield compared with feather meal and composted layer manure. However, soy protein and seabird guano were often similar to sodium nitrate in yield response and resulted in higher yields when compared with other sources of organic N, such as feather meal and composted layer manure. While feather meal and composted layer manure resulted in a 10 and 11% reduction in yield, respectively, there was no significant difference in tobacco value among treatments. Our results suggest that organic tobacco farmers have other options for N selection beyond the current feather meal standard.