Establishing application protocols for poultry litter and feather meal in organic Burley tobacco production
Information on nutrient management in organic Burley tobacco is limited. Unlike conventional nitrogen (N) sources, which are readily available for plant use upon application, organic N fertilizers require microbial mineralization to become plant available. As such, optimizing the synchrony of plant N demand and N fertilizer mineralization can be challenging. Two studies were conducted at the Mountain Research Station in Waynesville (W), North Carolina and the Upper Mountain Research Station in Laurel Springs (LS), North Carolina in 2018. Study one investigated the effects of application methods (broadcast, split application, and side dress) of pelleted, hydrolyzed feather meal (Nature Safe® 13-0-0) and composted chicken poultry manure (Harmony 5-4-3). Study two compared application rates (168, 224, 280, and 336 kg·ha-1) of both organic fertilizers. A conventional control (SQM 12-0-46 + 28-0-0 liquid UAN) was split applied (112 kg·ha-1 broadcast during field preparation and 112 kg·ha-1 side-dressed ten days after transplanting). Yields, quality, total alkaloid content, and leaf nitrate levels increased linearly with increasing application rates at LS. Leaf nitrate concentrations were highest in feather meal regardless of rate at LS. At both sites feather meal significantly increased total alkaloid content compared to poultry manure. In study two, application methods did not affect yield at LS; however, split application resulted in higher yields compared to broadcast application at W (4350 kg·ha-1 vs 3760 kg·ha-1, respectively). Similar to study one, alkaloids where higher in feather meal treatments (4.3 %) than poultry litter (3.8 %). The linear trend in application rates suggests that higher rates may be required to maximize yield. Furthermore, split application of fertilizer may benefit growers as it resulted in higher yields at LS and may protect against potential N leaching in case of significant early season rain events. Finally, feather meal may be a better option as it resulted in higher total alkaloids across both studies.