Impact of Farming Methods on Some Anti-nutrients, Nutrients and Toxic Substances of Cassava Roots

Abstract

This study was carried out to evaluate the effect of farming methods (organic and convectional) on some nutrients and heavy metals contents of cassava roots. Two cassava cultivars (TME 419 and pro vitamin A) were planted, employing organic and convectional farming methods. Within the organic farming, organic soil amendment was carried out, while in the convectional farming, synthesize fertilizers (NPK 15:15:15 and Maxi Calmag) were used. The organic amendment (compost manure) was formulated from poultry waste, cattle dung and wood sawdust in the ratio of 50%:25%:25% (volume to volume). The two cassava cultivars were planted and closely monitored for 10 months, applying all the relevant agronomic in relation to each farming method. Chemical analyses of the soil and cassava roots were carried out in accordance to standard methods. From the results, the farming methods had significant (p ≤ 0.05) effect on all the parameters (nitrate, copper, lead, iron, calcium and potassium) studied in the two cassava cultivars. The average nitrate content of the convectional cassava roots was 248.84 mg/kg, which was higher than the 108.59 mg/kg recorded in the organic cassava roots. In addition, the organic cassava roots had lower average calcium content (646.47 mg/kg) Compared to the convectional cassava roots (1788.36 mg/kg). However, significantly lower lead and copper contents of organic cassava roots were recorded, when compared with conventional cassava roots. The lower content of nitrate (a toxic substance) and other heavy metals (copper and lead) in the organic cassava roots, than in the convectional cassava roots shows the relevance of organic farming in modern agriculture.