Vol. 9, Issue 1, Part A (2025)

Experiments were conducted to investigate the allelopathic effects of neem (Azardirachta indica) leaf extract on selected field crops' seed germination and seedling vigor. Five crops viz., rice, maize, sorghum, finger millet, and black gram seeds were used in the study. Seeds of each crop were placed on filter paper saturated with six different concentrations of neem leaf extract (1%, 2%, 3%, 4%, 5%, and 6%), while water was used as the control. Qualitative and quantitative analysis of phytochemicals, including alkaloids, cardiac glycosides, terpenoids, steroids, saponins, phenolic compounds, flavonoids, carbohydrates, and proteins, was conducted using ethanol, chloroform, and diethyl ether extracts. The analysis revealed that neem leaves are richest in alkaloids (5.14%), followed by flavonoids (4.12%). The results showed that Azardirachta indica leaf extracts significantly reduced seed germination and seedling vigor in all crops. As the concentration of the neem leaf extract increased, germination percentages decreased across all crops, with reductions of 18% to 20% compared to the control. Blackgram exhibited the greatest reduction in germination, with germination rates dropping from 89% (water control) to 30% at the highest concentration of neem extract (6%). Regardless of crop type, seedling vigor also declined with increasing neem extract concentrations. Seedling vigor in the water control was recorded as 287.30, 723.1, 696.6, 348.6, and 232.16 for rice, sorghum, maize, black gram, and finger millet, respectively, while values in the 6% neem extract treatment were 161.2, 198.21, 226.4, 58.9, and 62.5, respectively. These results suggest that neem (Azardirachta indica) leaf extract exhibits allelopathic effects, inhibiting both seed germination and seedling growth across various crops.