Influence of Organic and Inorganic Zinc Sources on Zinc Availability in Soil and its Uptake by Barley

摘要

Land application of organic amendments alters soil physico-chemical properties and thereby may affect heavy metal bioavailability. The objective of this study was to investigate zinc (Zn) availability to barley (Hordeum vulgare L. cv. Makoei) in a clay loam soil amended with organic and inorganic Zn sources. A field experiment with completely randomized block design was performed with seven treatments in three replicates. A Zn enriched vermi-compost (800 mg Zn kg-1) was applied to the soil at three rates of 25 (V1), 50 (V2), and 100 Mg ha-1 (V3). To compare the effects of organic and inorganic sources, similar rates of Zn as ZnSO4 were also applied (Zn1, Zn2 and Zn3, respectively). An untreated soil sample was also considered as control soil (V0). Results showed that barley plants grown in soil treated with ZnSO4 accumulated significantly greater Zn in their root tissue compared to those grown in soil treated with vermi-compost. A significant increase in the shoot, spike, root, and leaf Zn concentrations was observed as the loading rate of vermi-compost increased. The Zn1 and Zn2 treatments caused a significant increase in the Zn spike concentration versus those grown in the control soil. However, at the greatest loading rate of Zn as ZnSO4 (Zn3), the Zn spike concentration and thereby the 1000-grain weight and the plant height decreased compared to the lower rate of Zn (Zn2). The results of this experiment point to the fact that the source and the loading rate of Zn are important factors in determining Zn phytoavailability.