Introduction: Water is one of the most important environmental factors that has a significant impact on the growth and development as well as the accumulation of active ingredients in medicinal plants. Low amounts of water during plant growth stages can cause irreparable damage to the growth and development as well as the active ingredients in plants. Irrigation interruption is a desirable solution for crop production under water shortage conditions. In principle, plants selected for irrigation interruption should be resistant to water shortage stress and its effects on growth and yield at different growth stages should be carefully examined. Soil nutrient management is of particular importance in the production of medicinal plants. On the other hand, moisture deficiency stress, as the most important factor limiting production, leads to a decrease in plant yield. Therefore, this study aimed to investigate the effect of animal manure on grain yield, grain components, and essential oil yield of black cumin under irrigation interruption conditions.
Material and Methods: The experiment was conducted in form split plot based on the randomized complete block design (RCBD) with three replications, at the Research Farm of the Campus of Agriculture and Natural Resources, Razi University in 2022. The treatments included fully rotted sheep manure (0, 10, 20, and 30 t ha-1) as the main plot and irrigation interruption (complete irrigation, interruption of irrigation from flowering stage, interruption of irrigation from grain filling stage) as the subplot. The final harvest was carried out at physiological maturity based on the observation of external symptoms, which included yellowing of the plants and lower leaves, browning of the follicles, and blackening of the grains (due to moisture loss). The measured traits included plant height, number of main branches, number of follicles, number of grains per follicle, 1000-grain weight, total dry weight yield, grain yield, essential oil percentage, essential oil yield, and harvest index. In order to data analyze, the SAS statistical software version 9.1 was used. First, the normality of the data was confirmed, the variance analysis of the data was performed using the GLM procedure, and then the least significant difference test was used to compare the means.
Results and Discussion: The interaction of manure application and irrigation interruption on yield and grain yield components was significant. The highest 1000-grain weight (1.69 g), total dry weight yield (251.5 g m-2), grain yield (108.7 g m-2), and grain essential oil yield (18.7 g m-2) and the lowest 1000-grain weight (1.39 g), total dry weight yield (125.3 g m-2), grain yield (44.3 g m-2), and grain essential oil yield (8.2 g m-2) were observed in the treatment of 30 ton ha-1 of manure and complete irrigation, and the treatment of no manure application and interruption of irrigation from the flowering growth stage, respectively. It seems that the use of higher amounts of manure and irrigation water increased the grain yield of black cumin by improving yield components such as the number of grains per follicle and the 1000-grain weight. The results also showed that the correlation of grain yield with total dry weight yield, harvest index, number of follicles m-2, number of grains per follicle, and 1000-grain weight was positive and significant.
Conclusion: In general, the results showed that in order to achieve maximum grain yield and grain essential oil yield, the treatment of 30 ton ha-1 of manure and complete irrigation was better. However, in the condition of 30 ton ha-1 of manure, there was no significant difference between interruption of irrigation from the grain filling stage and complete irrigation. Therefore, instead of completely irrigating in the field without reducing grain and essential oil yield, irrigation can be stopped at the grain filling stage, which in turn reduces the amount of water consumed in the field. |
