High lead (Pb) concentration in soils is becoming a severe threat to human health. It also deteriorates plants, growth, yield and quality of food. Although the use of plant growth-promoting rhizobacteria (PGPR), biochar and compost can be effective environment-friendly amendments for decreasing Pb stress in crop plants, the impacts of their simultaneous co-application has not been well documented. Thus current study was carried, was conducted to investigate the role of rhizobacteria and compost mixed biochar (CB) under Pb stress on selected soil properties and agronomic parameters in mint (Mentha piperita L.) plants. To this end, six treatments were studied: Alcaligenes faecalis, Bacillus amyloliquefaciens, CB, PGPR1 + CB, PGPR2 + CB and control. Results showed that the application A. faecalis + CB significantly decreased soil pH and EC over control. However, OM, nitrogen, phosphorus and potassium concentration were significantly improved in the soil where A. faecalis + CB was applied over control. The A. faecalis + CB treatment significantly improved mint plant root dry weight (58%), leaves dry weight (32%), chlorophyll (37%), and N (46%), P (39%) and K (63%) leave concentration, while also decreasing the leaves Pb uptake by 13.5% when compared to the unamended control. In conclusion, A. faecalis + CB has a greater potential to improve overall soil quality, fertility and mint plant productivity under high Pb soil concentration compared to the sole application of CB and A. faecalis.

Department of Agrochemistry Soil Science Microbiology and Plant Nutrition Faculty of AgriSciences Mendel University in Brno Zemedelska 1 61300 Brno Czech Republic

Department of Agronomy The University of Haripur Haripur Khyber Pakhtunkhwa 22620 Pakistan

Department of Animal Sciences Cornell University Ithaca USA

Department of Environmental Sciences Bahauddin Zakariya University Multan Punjab 60800 Pakistan

Department of Geology and Pedology Faculty of Forestry and Wood Technology Mendel University in Brno Zemedelska1 61300 Brno Czech Republic

Department of Soil and Environmental Sciences Faculty of Agriculture Gomal University Dera Ismail Khan KPK Pakistan

Department of Soil Science Faculty of Agricultural Sciences and Technology Bahauddin Zakariya University Multan Punjab 60800 Pakistan

Department of Technical Services Fatima Agri Sales and Services Bahawalpur Punjab Pakistan

Faculty of Chemistry Institute of Chemistry and Technology of Environmental Protection Brno University of Technology Purkynova 118 62100 Brno Czech Republic

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