Bio-fortification of Fe and Zn in rice (Oryza sativa L.)
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Date
2019
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Publisher
CCSHAU
Abstract
For the present investigation, fifteen surface soil samples from each North-Eastern district
(10) of Haryana under paddy-wheat cropping system were collected using GPS to study the distribution
of micronutrients (Fe and Zn), their contribution in paddy, release behaviour and finally the effect of Fe
and Zn on their bio-fortification in rice. To achieve the objectives, a laboratory, screen house and field
study was carried out. Laboratory and screen house study was conducted at CCS HAU, Hisar while
field study was carried out at CCS HAU Rice Research Station, Kaul during kharif 2017 on loamy soil
testing slightly alkaline in pH, low EC, low in available N, low to medium in available P, medium to
high in available K. Field experiment in a RBD with five replications was laid out in a plot size of (5m
x 4m) having five levels each of Zn [(0, 12.5 , 25.0 kg ha-1 as basal, foliar spray (0.5%) ZnSO4 at
Panicle initiation & Heading stages and 25 kg ha-1 as basal + foliar spray (0.5% ) ZnSO4 at Panicle
initiation & Heading stages] and Fe [0,50,100 kg ha-1 as basal, Foliar spray (0.5%) FeSO4 at 45 DAS
and 100 kg ha-1 as basal + foliar spray (0.5%) FeSO4 at 45 DAS]. Results showed significant
differences due to various treatments of Fe and Zn over their respective controls. The highest grain
yield was recorded with combined application of 25 kg Zn ha-1 as soil application + foliar spray of Zn
(0.5%) at Panicle initiation and heading stages which was significantly superior to (Zn 0.5% foliar
spray @ 45 days after sowing which in turn on a almost par with the treatment of 25 kg Zn ha-1 as soil
application alone. Likewise, with Fe fertilization grain yield also differed significantly with the
treatments over control. The same was true for straw. The data on harvest index of Fe & Zn, and
protein content revealed that their values differed significantly with various treatments of Zn or Fe over
their respective controls. A screen house study also supported these findings. The laboratory study on
fractionation of Zn and Fe showed that the different forms of Zn and Fe were mainly associated in the
residual fraction and the order of preponderance of Zn fractions was Ex-Zn<OM-Zn<CaCO3-
Zn<FeMNOX-Zn<Res-Zn while that of Fe fractions was OM bound Fe <exchangeable Fe < carbonate
bound Fe < iron and manganese oxides bound Fe < residual Fe in studied site soil samples. Study on
release behavior of these micronutrients (Zn & Fe) showed that as the period of incubation increased, a
gradual decrease in DTPA-extractable Zn of soils was noticed up to 60 DAI, while the amount of
DTPA-extractable Fe in general increased initially up to 30 DAI and then consistent decrease was
observed towards the later period of incubation.