Biochar Reduces Phyto-Availability of Cadmium for Fenugreek Grown in a Sandy Soil.

Ahmed H. El-Naggar ^a,b , Mohamed I. Al-Wabel^a

^a Department of Soil Science, King Saud University, P.O. Box 2460, Riyadh, 11451,Saudi Arabia.

Tel.: +966 1 4699783 ; fax: +966 1 467 8440. 

b Department of Soil Science, Faculty of Agriculture, Ain Shams University, 68 Hadayek Shobra, P.O. Box 11241, Cairo, Egypt

The positive impacts of biochar amendments on agricultural productions and soil health is reported in several scientific studies. Biochar could be used to alleviate the phytotoxicty and chemical activity of pollutants is soils. The aim of this study was to investigate the effect of biochar soil amendments on the phyto-availability of Cadmium to plants grown in cadmium contaminated areas. Sandy soils were treated with increasing levels of CdCl₂ to bring the soil total Cd concentration to 0, 5, 10, 25 and 50 mg Kg^-1. After two weeks, biochar produced from the woody wastes of Conocarpus erectus sp were mixed with  Cd contaminated soil at rates of 0, 1, 2 or 3 g per 100 g soil. Treated soils were packed in plastic pots, where 60 seeds of Fenugreek (Trigonella foenum-gracecum L.) were sown in each pot. After 33 days from plantation, shoot and root biomass were harvested.  Results showed that biochar addition significantly reduced Cd uptake by plants. At application rate 50 mg Cd per Kg soil, shoots Cd content were reduced from 62 ppm in the control ( 0 Biochar) to 46 and 38 ppm for 1.5 and 3% biochar application. Results showed that recovery of available Cd in the soil by AB-DTPA extraction was significantly reduced by the application of biochar. Soil microbial biomass C was enhanced at levels of 1 and 2 g biochar per 100 g of soils. In general, results refers to the potential use of biochar for reducing the negative environmental impacts of increased soil levels of heavy metals specifically in areas characterized by limited soil/water resources