SPECIATION OF COPPER IN VEGETABLE AND PADDY SOILS OF PENINSULAR MALAYSIA

摘要

Copper speciation in vegetable and paddy soils from selected areas in Peninsular Malaysia has been investigated to understand the Cu behaviour in agricultural soils of the humid tropic country. Copper concentrations in the Easily Leacheable and Ion Exchangeable (ELFE), Acid Reducible (AR), Organic Oxidizable (OO) and Resistant (RR) fractions in soil samples were determined. Except for the exceeded Cu values in Serdang (1849.65 mg/kg) and Kajang (2055.66 mg/kg), most of the vegetable soils studied showed normal range (2.01-116.40 mg/kg) of total Cu content in soils. Copper in vegetable soils was primarily concentrated in the organic bound form (OO), followed by the resistant form (RR), whilst the bioavailable Cu (ELFE) was low (less than 0.75 mg/kg). However, Cu soils in Cameron Highlands and Cheras were predominant in the resistant form (RR), followed by the organic bound form (OO fraction), and contain higher bioavailable Cu (ELFE) (5.26 mg/kg and 11.80 mg/kg respectively). Copper in the paddy soils studied were predominant in the resistant form (RR), followed by the organic bound form (OO). The bioavailable Cu (ELFE) was very low in the inland valley paddy fields (Besut), and undetected in the clayey and silty soils of marine alluvium (Pendang, Arau, Yan and Bumbung Lima). The predominant unavailable Cu in most agricultural soils of Peninsular Malaysia were due to the slightly acidic soil condition, occurences of oxides of Fe and Mn as well as clay minerals, and higher organic matters content in soils.