Effects of Gyttja and Gyttja-Derived Biochar on Soil Biological Properties and the Growth of Common Bean (Phaseolus vulgaris L.)

The use of organic amendments is crucial in revitalizing soil fertility and ensuring long-term agricultural sustainability. Gyttja, a mineral- and organic-rich sediment, and its biochar form offer promising potential to improve soil health and plant performance. This study investigated the effects of raw gyttja and gyttja-derived biochar on soil biological properties and the growth performance of common bean (Phaseolus vulgaris L.) under semi-controlled greenhouse conditions. Treatments included three application rates (10, 20, and 30 t ha-1) of both gyttja and biochar, along with an unamended control. Results showed that gyttja significantly enhanced shoot and root lengths, SPAD values, and urease activity, indicating improved nitrogen cycling and plant nutritional status. In contrast, biochar applications were more effective in increasing biomass accumulation, root elongation, and dehydrogenase activity, reflecting enhanced microbial respiration. Correlation analysis revealed strong associations between physiological plant responses and soil enzymatic activity. The findings underscore the complementary contributions of gyttja and its biochar to soil enrichment and plant development. Their joint use could serve as an effective method for boosting crop yields and rehabilitating poor or degraded soils.