Compost-mixed Biochar Improves Saline Soil Properties and Enhances Brassica Oleracea var. Capitata physio-biochemical Responses

Abstract The present research aimed to correlate changes in saline soil properties and cabbage agro-physiological attributes under compost-biochar co-application. The treatments used prior to cabbage cultivation were soil applications of compost/biochar mixtrure (CMB) at rates of 0 (CMB 0 ), 10 (CMB 10 ), and 20 (CMB 20 ) t ha –1 in a randomized complete block design with three replications. The CMB 20 was the effective practice for reducing dry bulk density, saturated hydraulic conductivity, pH, and electrical conductivity, while improving total porosity, water-holding pores, soil moisture at field capacity, organic matter, cation exchange capacity, and nutrient availability. CMB 20 also improved plant relative water content, membrane stability index, and chlorophyll a and b concentrations. Hydrogen peroxide and malondialdehyde decreased by 13.5% each under CMB 20 treatment. Cabbage plants grown in saline soil produced greater phenolics content (56.0%) with higher superoxide dismutase (17.2%) activity in CMB 20 -treated plots than CMB 0 . Leaf nitrogen, phosphorus, and potassium contents enhanced by 10.1, 28.1, and 18.4%, respectively, compared with CMB 0 . Finally, CMB 20 achieved the maximal improvements in leaf number plant − 1 (41.8%), leaf area plant − 1 (216.2%), above-ground biomass (174.5%), head circumference (38.2%) and marketable yield (101.6%) of cabbage. It could be concluded that amending saline soil with CMB is regarded as a promising treatment for alleviating the salinity hazards on cabbage via modulating soil properties and physiological responses. Hence, CMB application, 20 t ha –1 , can be recommended as an agronomic practice for cabbage production to obtain high yield and quality.