Improving Acacia auriculiformis seedlings using microbial inoculant (Beneficial Microorganisms)

A microbial inoculant, known as effective microorganisms (EM), was applied to determine its efficacy on seed germination and seedling growth in the nursery of Acacia auriculiformis A Cunn. ex Benth. The seedlings were grown in a mixture of sandy soil and cow dung (3:1) and kept in polybags; EM was poured at different concentrations (0.1%, 0.5%, 1%, 2%, 5% and 10%). Seed germination rate and growth parameters of seedlings shoot and root lengths, fresh and dry weights of shoots and roots, vigor, volume, and quality indices and sturdiness were measured. The nodulation status influenced by EM was also observed, along with the measurement of pigment contents in leaves. The highest germination rate (72%) was observed in 2% EM solution while the lowest (55%) was found in control treatment. The highest shoot and root lengths (30.6 cm and 31.2 cm respectively) were recorded in 2% EM and were significantly (p <0.05) different from control. Both fresh and dry weights of shoots were maximum (8.66 g and 2.99 g respectively) in 2% EM, whereas both fresh and dry weights of root were maximum (2.56 g and 1.23 g respectively) in 5% EM solution. Although the highest vigor index, volume index, and sturdiness (4450, 628 and 67.5 respectively) were found in 2% EM, the highest quality index (0.455) was found in 5% EM solution. The nodule number was higher at a very low (0.5%) concentration of EM but it normally decreased with the increase of concentration. The contents of chlorophyll a, chlorophyll b, and carotenoid were maximum (43.26 mg.L-1, 13.56 mg.L-1.:land 17.99 respectively) in 2% EM. Therefore, low concentration of EM (up to 2%) can be recommended for getting maximum seed germination and seedling development of A. auriculiformis in the nursery.