Page 91 - C:\Users\am_se\OneDrive - Higher Education Commission\Desktop\FlipBook\

International Conference on

Recent Trends in Environmental Sustainability

ESCON22/ETERM/30
Iodine uptake and growth response of maize (Zea mays l.) in limed and humic acid
amended soil fertilized with zinc iodide and zinc iodate

*
Asif Naeem and Muhammad Aslam
Soil and Environmental Sciences Division, Nuclear Institute for Agriculture and Biology,
Faisalabad 38000, Pakistan
Correspondence: scoutuaf@gmail.com

Abstract
Low iodine concentration in cereal grains results in its low dietary intake, and populations
relying on cereals as major staple foods are widely deficient in iodine. Therefore, iodine
enrichment of cereal grains through iodine fertilization represents a sustainable solution to
iodine deficiency. However, iodine uptake by plants is thought to be affected by the form of
iodine applied to the soil, soil pH and organic matter content. Thus, we investigated time-
dependent water-soluble iodine in soil, its concentration and uptake by shoots and grains of
maize in limed and humic acid amended soil fertilized with zinc iodide and zinc iodate. Iodine
-1
was applied at the rate of 3 mg kg soil while lime and humic acid were applied at the rate of
-1
3 g kg soil. Water soluble iodine (WSI) in iodide fertilized soil achieved a steady state level
within one month after incubation, except for limed soil where it showed a slight decline after
nd
2 month of incubation. In iodate fertilized soil, WSI was 2 – 6 folds higher than iodide
-1
fertilized soil and it gradually decreased from 938 µg kg soil after one-month of incubation
-1
to 562 µg kg soil after 3 months of incubation. Humic acid did not affect WSI in iodide
fertilized soil but decreased it by 24-48% in iodate fertilized soil. Iodine application tended to
decrease grain yield, leaf and stalk dry matters but effects were non-significant (p ≤ 0.05).
Compared to iodide fertilized soil, iodate fertilized soil resulted in 5 to 7 folds higher iodine
concentration in leaves and 5 - 11 folds higher concentration in stalks. Iodate fertilization to
limed soil resulted in 2 folds higher iodine concentration in leaves and up to 3 folds higher in
stalks. A minor quantity of the up taken iodine was translocated to grains, and even the
-1
maximum achieved concentration (200 µg kg , with iodate) could support only one-third of
the recommended dietary allowance (RDA). It is concluded that soil iodine fertilization to
maize could partially support the RDA, however, using shoot part as animal fodder could
generate substantially iodine intake through secondary route.

Keywords: Biofortification; Humic acid; Iodine; Lime; Maize; Zinc Iodide; Zinc Iodate

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

58