| Soil tillage has a pronounced effect on the growth of flue-cured tobacco (Nicotiana tabacum L.), weed suppression during the production season, and soil physical properties. With rising input costs and increases in farm size, North Carolina tobacco producers stand to benefit from alternative approaches to crop production. Three research projects were conducted in North Carolina from 2012 to 2014 to quantify the impacts of soil tillage on flue-cured tobacco growth, weed suppression, and soil physical properties.;In one project, two primary tillage methods, two herbicide programs, and two hand weeding programs were evaluated to quantify their impact on tobacco production and two subsequent cropping seasons of cotton the following years. In one research period, deep tillage increased tobacco yield over shallow tillage. In addition, deep tillage contributed to the reduction of early season Palmer amaranth density in both research periods. Late season Palmer amaranth control was attributed to sulfentrazone application prior to transplanting, as row ridging and repeated post-transplanting cultivation are believed to negate the effects of weed seed burial with deep tillage. In addition, hand weeding increased leaf yield and value. Deep tillage did not contribute to reduced Palmer amaranth populations in cotton. Palmer amaranth suppression in cotton was a result of sulfentrazone application in tobacco and hand weeding efforts in years one and two of the crop rotation. Results favor the use of sulfentrazone in tobacco and hand removal of large Palmer amaranth as needed.;In the second project, three primary tillage methods were evaluated in the Coastal Plain (fall ridging, spring ridging, and strip-tillage) and Piedmont (fall ridging, spring ridging, and rotary tillage ridging) regions of North Carolina. After transplanting and after final harvest, soil physical property measurements (bulk density, porosity, water content, and resistance) were collected. In addition, leaf yield, quality, and value were assessed at the end of the season. Results indicate that all three tillage systems evaluated in the Coastal Plain are acceptable for flue-cured tobacco production within that region. Alternatively, in the Piedmont region, results indicate that fall ridging could result in yield loss due to increased soil resistance, specifically when soil moisture is reduced.;In a third project, 10 different fertilizer programs were evaluated in the northwestern Piedmont region of North Carolina. Nine treatments were evaluated utilizing all possible combinations of three nitrogen rates from liquid 28% Urea-Ammonium-Nitrate (56, 72, and 95 kg N ha-1), three phosphorus rates from granular Triple Superphosphate (0-46-0) (0, 28, and 56 kg P 2O5 ha-1), and one potassium rate from granular sulfate of potash magnesia (0-0-22) (84 kg K2O ha-1). One additional treatment of 560 kg 8-8-24 ha-1 and 72 kg 15.5-0-0 (56 kg N, 45 kg P2O5, 134 kg K2O ha -1) was included for comparison between alternative nitrogen sources and recommended rates of phosphorus and potassium and a traditional fertilizer program for the specific region. Differences between traditional dry and alternative liquid fertilizer sources were not observed, indicating that alternative fertilizer sources are acceptable in the production of flue-cured tobacco. Tobacco yield was increased as nitrogen application rates were increased above 56 kg ha -1; likely due to excessive rainfall experienced in 2013. Leaf quality and value were not affected by nitrogen application rates. The exclusion of phosphorus from production did not reduce early season growth. In addition, increasing phosphorus application rates did not improve yield, quality, or value.;Based on the results obtained from these studies, flue-cured tobacco producers in North Carolina should consider alternative management practices where feasible. Many of the practices evaluated reduce costs without reducing financial return. In addition, producers should not expect reductions in leaf yield or quality. |
PDF Full Text Request