Mitigating potential of biochar application on the negative impact of soil salinity on plant

Biochar is a pyrolysis product of organic material and has increasing concern to use in plant growth and development. Its application is getting more common method to enhance crop production particularly in soils under environmental stresses such as heavy metals, drought or salt. In this study, biochar effect was evaluated on growth of salt sensitive crop Phaseolus vulgaris (L.) under saline conditions. Greenhouse grown plants were treated with 3 salt concentration (0, 25 and 50 mM NaCl) and 3 levels of biochar (0, 5 and 15 t/ha). The biochar was produced by thermal degradation of olive branches, a mixture of hardwood (70 %) and softwood (30 %) by slow pyrolysis at 400 °C. NaCl adsorption capacity of biochar was conducted by electrical conductivity (EC) analysis. Plants growth parameters (length and biomass) were recorded from seedling to flowering stage. Salinity exposure caused an inhibition in root and shoot growth and flower and fruit development of P. vulgaris in parallel to increasing concentration. Salinity caused oxidative stress through increasing hydogen peroxide content and cell membrane permeability of leaves. The mitigating effect of biochar on saline stress was determined by measuring less hydrogene peroxide content and cell membrane hazard, and higher ratio on root and shoot growth, flower and fruit development of plants. Salinity stress effect was alleviated by biochar that was more prominent in 5 t/ha than 15 t/ha treatment for all NaCl concentrations applied. The biochar has high NaCl adsorption capacity determined by lower EC levels. Results indicated that biochar has a remediation potential on saline soil and it is a promising application to increase crop yields under normal and abiotic stress conditions.