Comparison of the Effects of Iron-Enriched Spinach and Sugar Beet Leaf Composts with Ferrous Sulfate and Iron Sequestrene on Iron Availability in the Sorghum Plant in Calcareous Soil

Abstract

Mixtures of iron salts and organic matter such as manure, compost, sewage sludge and peat have been used successfully in controlling iron chlorosis in various crops. The aim of the present study was to optimize the effectiveness of natural organic substances by enriching them with iron sulfate on iron availability in sorghum. For this purpose, spinach leaves and sugar beet leaves, as ferrophyll and iron-enriched plants, were incubated with different quantities of iron sulfate. The effects of these iron-enriched composts, iron sulfate and Sequestrene 138 on iron availability in sorghum in calcareous soil were studied in a greenhouse experiment. The DTPA-AB extractable iron of soil, the total iron concentration and the chlorophyll of the plant leaves were all measured. Soil applications of the iron-enriched spinach leaves and sugar beet leaves composts and iron sulfate significantly increased the DTPA-AB extractable iron of the soil, but the spinach leaves and sugar beet leaves composts had no significant effect compared to the control and Sequestrene groups. The plant analysis indicated that the spinach leaves compost significantly increased the total iron concentration in the leaves compared to the control group and even more than the Sequestrene group. The iron-enriched spinach compost increased the total iron concentration compared to the control group, but had no significant effect compared to the sequestrene group. All the iron-enriched composts had same effect as the sequestrene group on the chlorophyll levels in the leaves and significantly increased this level compared to the control group, but the spinach leaves and sugar beet leaves composts significantly decreased the level of chlorophyll in the leaves compared to the control group.