Influence of Different Weed Interference Durations on the Yield and Oil Content of Black Cumin (Nigella sativa L.).

In the context of organic farming where the use of herbicides is restricted, blackseed is highly vulnerable to weed pressure because of its sensitivity to its effect. We therefore designed the project to determine when blackseed should receive protection from weeds. For this purpose, an experimental trial was conducted using a Randomized Complete Block design with seven treatments and three replicates using an experimental area located at the Grdarasha Research Field, Salahaddin University, Erbil, Iraq. In addition to weed-free plots and untreated weed infested plots; there were also weed-free plots maintained for 15, 30, 45, 60 & 75 Days After Emergence.
According to the findings from this study, a long time weed interference significantly reduced growth, seed yield and oil content. Plots known to have been kept free of weeds were found to yield the highest seed yield (1128.4 kg ha-1) and lowest yield loss (9.7%) were achieved in the weed-free plots and in durations where weeding was maintained for at least 30 DAE. In full-season weed-free, the large amount of oil content and oil yield were 38.75 and 437.25kg ha-1, this is primarily attributed to it producing a greater seed yield because of no early weed competition and the lowest in the weedy check plot (27.92 and 63.534kg ha-1). At the same time the highest total dry weight (176.65 g m2) and the highest number of weeds (286.67 weeds m²) occurred in the weedy check plots. The period around 45 DAE was identified as the most critical period for weed control; delaying weed control beyond this period resulted in the greatest reductions (>10%) in yields and total oil yields. The findings of this study show the major importance of timely control of weeds for increasing Nigella sativa production and decreasing competition associated with weed control.