Influence of Biochar based Organic Fertilizers on Growth and Concentration of Heavy Metals in Tomato and Lettuce in Chromite Mine Tailings Contaminated Soil
Influence of Biochar based Organic Fertilizers on Growth and Concentration of Heavy Metals in Tomato and Lettuce in Chromite Mine Tailings Contaminated Soil
Faiza Altaf1, Shamim Gul1,2*, Tasawar Ali Chandio3, Gul Bano Rehman1, Attiq-ur-Rehman Kakar4, Sami Ullah4, Naqeebullah Khan4, Umbreen Shaheen5, Muhammad Naeem Shahwani6, Muhammad Ajmal7 and Misbah Manzoor8
ABSTRACT
Chromite mining activities in Balochistan are causing serious heavy metal contamination in agricultural soils. Due to high adsorption capacity of biochar, its amendment in heavy metal-contaminated soils is known for reducing soil toxicity to crops. This pot-based study investigated influences of wood-derived biochar and farmyard manure-derived (cow dung-derived) biochar as mixtures with air-dried poultry manure on the growth and concentration of heavy metals in edible tissues of tomato and lettuce. These biochars were separately mixed with poultry manure as 1:1 ratio on air-dry weight bases. Soil was contaminated with chromite mine tailing debris at 2% amendment rate (980 g soil + 20 g debris). Biochar-poultry manure mixtures were applied in soil at 10% and 20% amendment rates (respectively, 900 g soil + 100 g mixture and 800 g soil and 200 g mixture of poultry manure and biochar in 1:1 mixture ratio). After harvest of tomato, lettuce was grown in the same soil. As compared to control, amendments of biochar-poultry manure mixtures had a significantly positive influence on growth of both crops. There was ~ 254.49% - 871.9% (~3.5 – 9 fold) increase in aboveground biomass of tomato and 25.67% – 94.59% increase in aboveground plant biomass of lettuce. These fertilizers also increased significantly water use efficiency by ~3.5 – 12.5 times (364.8% - 1166.6%) of tomato plants (as only tomato plants were analyzed for WUE). Furthermore, these amendments reduced concentration of heavy metals in plants of both crops. As compared to contaminated control treatment, amendment of biochar-poultry manure mixtures increased the concentration of soluble mineral phosphorus by 288% - 914% in soil. Our study suggests that amendment of wood-derived biochar and cow manure-derived biochar as mixtures with poultry manure, significantly improved growth of both crops and increased concentration of bioavailable phosphorus in soil.
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March 2021
Vol. 37, Iss. 1, Pages 1-330
