Use of Composting Manure to Improve Plant Iron and Zinc

Abstract

Laboratory experiments were conducted to determine the influence of three types of decomposing fresh organic materials [pig manure (PM), Astagalus sinicus (AS), and Alternanthera philoxeroides (AP)] on dissolution of Fe2O3 and ZnO and also the use of a loamy calcareous soil as an alternative source of iron (Fe) and zinc (Zn). Levels of Fe and Zn concentrations in composting solutions changed with composting time. The maximum levels of solution Fe resulting from the decomposition of the three organic materials were 20, 612, and 348 mg L−1 for PM, AS, and AP, respectively, when the soil was supplied as the Fe source, and 17, 32, and 16 mg L−1 when Fe2O3 was supplied as the Fe source. Corresponding maximum levels of solution Zn were 0.9, 0.7, and 1.3 mg L−1 and 35, 171, and 103 mg L−1 when the soil and ZnO was supplied as the Zn source respectively for the same three organic materials.