Effects of Saline Water Irrigation and Biochar Amendment on Okra Growth and Nutrient Leaching in Coastal Saline Soils

Excess soluble salts in the soil and irrigation water creates difficulties for plant growth and lowers nutrient availability in the soil. Organic ameliorants such as biochar are believed to be one of the effective treatments for soil improvement and salt stress alleviating. To access the response of different types of salt in irrigation water and bamboo biochar amendment on okra growth and nutrient leaching in coastal saline soils, both column and pot experiments were carried out from 2018 to 2019 in Nanjing, China. The experimental results suggested that okra growth and yield were reduced notably under the saline condition in contrast with the control treatment. Anthocyanin accumulation, which is a sign of growth stress, was decreased after the application of different types of salt. Furthermore, the application of different types of salt effectively increases malondialdehyde (MDA) content in sodium sulfate (Na2SO4) and sodium chloride (NaCl) treatments at both 2.0 and 4.0 dS/m. Meanwhile, MDA was reduced in CaCl2 and MgCl2 treatments at both 2.0 and 4.0 dS/m. Nevertheless, bamboo biochar remarkably ameliorated okra seed germination, growth process, and yield due to salt stress. Besides, the leaching of nitrate, total nitrogen and total phosphorus is significantly reduced in the case of biochar application. In conclusion, our study suggested that bamboo biochar is one of the alternatives of ameliorant to improve the productivity of plants in coastal saline soils.