Evaluation of N rates and biomass management on pearl millet yield and N uptake in a rotation.

摘要

Pearl millet (Pennisetum glaucum L.), a relatively new crop in Canada, can potentially provide major economic benefits through cover cropping. This study examined the effect of nitrogen (N) rate and biomass management on dry matter and N uptake of pearl millet in a rotation involving flue-cured tobacco (Nicotiana tabacum L.). In June 2005 and 2007, pearl millet (var. CFPM 101) was planted under three N rates (60, 120, and 180 kg ha-1) using two systems of aboveground biomass management: single cut with biomass removed from the field (BS1) or two cuts with biomass retained in the field (BS2). In addition, winter rye was established and managed with current practices for winter rye in rotation with flue-cured tobacco. Millet biomass increased up to the highest N rate in BS2, but in BS1 biomass values at the 120 and 180 kg N ha-1 rates were not statistically different (P<=0.05). Depending on treatment, millet biomass was higher than the winter rye biomass by about 60% to 214% in 2005 and 20% to 145% in 2007. In the fall when millet was grown, nitrate-N concentrations in the top 20-cm soil samples were higher in BS1 than in BS2. Results indicated that different harvesting methods required different rates of N fertilization. Therefore, more research to develop N recommendations for the different production options is needed.