OICC Press International Journal of Recycling of Organic Waste in Agriculture 2251-7715 14 2 2024 10 03 Improvement of soil quality through biochar in rice under wastewater irrigated soil: Effects on heavy metals reduction 10.57647/ijrowa-037z-qk22 EN Sayon Mukherjee Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences; Banaras Hindu University; Varanasi, 221005, Uttar Pradesh, India https://orcid.org/0000-0002-1007-755X Satish Kumar Singh Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences; Banaras Hindu University; Varanasi, 221005, Uttar Pradesh, India https://orcid.org/0000-0001-7321-4630 Raimundo Jiménez Ballesta Department of Geology and Geochemistry, Autónoma University of Madrid, 28049, Madrid, Spain https://orcid.org/0000-0002-4048-0892 Abhik Patra Krishi Vigyan Kendra, Narkatiaganj, West Champaran, 845455, Bihar, India (Dr. Rajendra Prasad Central Agricultural University, Bihar, Pusa, Samastipur, India) https://orcid.org/0000-0003-3415-7180 Surendra Singh Jatav Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences; Banaras Hindu University; Varanasi, 221005, Uttar Pradesh, India https://orcid.org/0000-0003-4049-2444 Journal Article 2024 10 03 Purpose: Rice, a global staple, can accumulate high levels of heavy metals especially Chromium (Cr) when grown in a soil irrigated with tannery effluent over time, potentially reaching toxic levels for human consumption. Biochar offers a cost-effective solution by binding these heavy metals in soil, reducing their bioavailability and mitigating health risks. The present study offers a two-way solution of reducing weed load of agricultural fields through parthenium biochar preparation and its application in Cr contaminated soil with aim of its lower accumulation in the edible part of the crop.   Method: The investigation consists of ten treatments in completely randomized design with three replications using simple and concentrated H3PO4 and 1 M FeCl3 modified biochar at graded dose and one biochar untreated control. All treatments receive a recommended dose of NPK fertilizers. Results: Our study shows that biochar produced from parthenium can reduce uptake of heavy metals in the plant body. Moreover, modification of biochar by H3PO4 and FeCl3 hastened the metal fixation and further reduced the metals accumulation in different parts of plant body depicted by lowering translocation factor (TF) along with translocation coefficient (TC). Conclusion: Overall, application of biochar is proven to reduce the metals accumulation in rice plant parts and grains rendering it a good amendment. Research Highlights Biochar and its subsequent modification reduce the heavy metals content in different plant parts of rice Application of H3PO4 modified biochar at 10 t ha-1 has declined the root concentration of Cr alone by 24.5% FeCl3 modified biochar also reduced all heavy metals uptake in different plant parts Performance of modified biochar at lower rates can produce statistically similar results with the higher dose of simple biochar Reduction of translocation coefficient and translocation factor within plant emphasizes the beneficial effect of biochar application to crop