Relationships between available zinc and its fractions in the presence of vermicompost

摘要

A field experiment was conducted to study the role of vermicompost (VC) in the availability of zinc (Zn) in rice soil by Zn incubated with verrnicornpost at ratios of 1:10, 1:20 and 1:30. Experimental result indicated that available form (DTPA-Zn) and all species of Zn were progressively increased at lower level of Zn (2.5kg/ha) in combination with vermicompost at ratios of 1:10 to 1:30. In many cases, cornplexation of organic Zn with organic ligands resulted in decreased adsorption on mineral colloids. The highest value of available Zn is recorded in 1:10 ratio of Zn enriched with verrnicompost due to the formation of water soluble (WS), organically complexed (OC) and manganese oxide bound (MnO) Zn species. Among the different species of Zn the highest value was recorded in the form of MnO, followed by OC, amorphous sesquioxide bound (AMRO), crystalline sesquioxide bound (CRYRO) and WS fractions. The present study indicated that Zn (5kg/ha) incubated with vermicornpost (50kg/ha) (1:10) fertilizer promotes the availability of DTPA-Zn in submerged soils.