Growth Improvement of Sweet Basil (Ocimum basilicum L.) Irrigated with Saline Water Using Biochar and Spirulina Algae Extract

Abstract

The current study aims to use the foliar treatment with Spirulina algae extract (SP) at rate 2.5g/L and biochar (BC) at rate 2% as soil amendment to alleviate the negative effects of salinity on basil plants. The irrigation with 5 dS/m saline water reduced the plant height, leaf number, branch number, leaf area, total chlorophyll, fresh, and dry weight by 10, 31,31,40, 55, 46, and 33%, respectively, compared to the fresh water. The combined addition of BC and SP (SP+BC) to the saline irrigated plants significantly increased the last above-mentioned growth parameter by 6, 21, 50, 45, 170, 8, and 31% respectively compared to the saline water without addition. The increase in branch number is not significant. BC and SP significantly (p < 0.05) increased the soil organic matter (SOM). The content of SOM can be arranged in the descending order: BC > SP > C. The irrigation of basil plant with saline water significantly decreased the total N, P and K in basil shoots at rate 31, 61, and 24%, respectively, compared to the fresh water. The addition of BC+SP to the saline irrigated basil caused increases in N, P, and K content by 90, 116, and 60% compared to the saline water without addition. Overall, the results of this study explained that using Spirulina algae extract and biochar is a good solution for improving the growth of basil plant under salinity condition.