Effect of Organic Substances on Plant Growth in Copper Contaminated Soils

A pot experiment on effect of peat and compost on copper absorption of ryegrass growing in copper contaminated soils was conducted. Results of the experiment showed no matter whether the organic substance was applied or not, the copper content in either the aerial or the ground part increased with the contamination level,with that in the latter doing much more significantly than in the former.The copper contents in the aerial and ground parts of the ryegrass were significantly,on average about 30%,lower in treatment peat and treatment compost.The effect of peat on reducing copper contents in both parts of the ryegrass decreased with the rise in copper contamination level,whereas the effect of compost remained significant even at the highest contamination level,and peaked at the contaminatio n level of 400 mg/kg.The effects of the two organic substances were closely associated with soil pH,and lasted throughout three crops of ryegrass.