Effect of tillage practices amended with burnt rice husk dust on chemical properties of degraded sandy clay loam and impact on soil and cocoyam (Xanthosomonas sagittifolium) in Abakaliki southeast Nigeria

The objective of this study was to find out the effect of tillage practices amended with burnt rice husk dust on soil chemical properties, content of carbohydrate, corm nutrient, heavy metal and yield of cocoyam in a degraded sandy clay loam. The field experiment was in split plot in randomized complete block design with six treatments. The treatments were; mound tillage (no treatment), ridge tillage (no treatment) mound + 10 t ha^-1 burnt rice husk dust (MBRDH₁₀), Ridge + 10 t ha^-1 burnt rice husk dust (RBRHD₁₀), mound + 20 t ha^-1 burnt rice husk dust (MBRHD₂₀) + Ridge +20 t ha^-1 burnt rice husk dust (RBRHD₂₀). Tillage practices amended with burnt rice husk dust significantly increased soil chemical properties compared to tillage practices alone. Soil extractable carbohydrate (cold water soluble, hot water soluble, dilute acid soluble) content was increased in tillage practices amended with rice husk dust. Corm nutrient content and shoot heavy metal (Cu, Pb, Zn, Fe) were significantly higher in tillage practices amended with burnt rice husk dust than tillage practices alone. The heavy metal was increased to levels that are non toxic to humans in food crops in the amended plots. The use of burnt rice husk dust as soil amendment could be recommended for reclamation of the productivity of degraded soil of the area and improve in crop quality without increase of heavy metal content of crops to toxic levels.