ASSESSMENT OF ZINC USE EFFICIENCY IN MAIZE-MAIZE CROPPING SEQUENCE
Loading...
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A field experiment was conducted at Krishi Vigyan Kendra, Jorhat farm,
Kaliapani, Teok, Assam Agricultural University during 2018-19 and 2019-20 to study
the influence of zinc fertilization on zinc fractions in soil, its relationship with important
soil properties, yield, nutrient uptake and zinc use efficiency in maize-maize cropping
sequence. The experiment was laid down in a randomized block design (RBD) with
twelve treatments consisted of zinc applied as soil with or without foliar application
through zinc sulphate and zinc oxide nano particle (ZnO NPs).
Distribution of different zinc fractions in soil were assessed after harvest of each
crop in the sequence. Perusal of experimental findings revealed that zinc fertilization
had a significant influence on different zinc fractions in soil during both the years under
investigation. The study revealed that among the zinc treatments, soil application of Zn
@ 3.75 kg ha-1 in combination with foliar application of 500 ppm ZnO NPs exhibited
the highest water soluble plus exchangeable-Zn content of 1.10 mg kg-1 in soil. The
highest concentration of complexed-Zn (2.95 mg kg-1), amorphous sesquioxide-bound-
Zn (4.11 mg kg-1), crystalline sesquioxide-bound-Zn (3.76 mg kg-1), residual-Zn
(125.65 mg kg-1) and total-Zn (137.33 mg kg-1) were recorded in the treatment receiving
soil application of Zn @ 7.5 kg ha-1. Among the zinc fractions studied, the concentration
and percent contribution of water soluble plus exchangeable-Zn to total-Zn was the
lowest while residual-Zn fraction contributed the highest to the total soil zinc pool. Path
coefficient analysis showed that the water soluble plus exchangeable-Zn had the highest
contribution towards the DTPA extractable-Zn in soil. The distribution of different zinc
fractions at post-harvest soil was found in the following order: water soluble plus
exchangeable-Zn < complexed-Zn < crystalline sesquioxide bound-Zn < amorphous
sesquioxide bound-Zn < residual-Zn. All the fractions of zinc were found to be
significantly and positively correlation with each other indicating existence of dynamic
equilibrium of zinc in soil.
Zinc fertilization exerted a significant influence on available nutrient status of
soil. The highest available nitrogen content of 182.50 kg ha-1 was found in the treatment
receiving soil application of Zn @ 3.75 kg ha-1 in combination with foliar application of
500 ppm ZnO NPs. The available phosphorus content in soil was decreased with zinc
fertilization and thus, soil application of Zn @ 7.5 kg ha-1 recorded the lowest available
phosphorus content of 19.45 kg ha-1, while the highest phosphorus content of 23.74 kg
ha-1 was recorded in the control. However, no significant influence of zinc fertilization
on available potassium, exchangeable calcium and exchangeable magnesium content in
the post-harvest soils were observed. The highest available sulphur content of 25.50 kg
ha-1 was registered in the treatment receiving soil application of Zn @ 7.5 kg ha-1. In
respect of content of available micronutrients in soil, the DTPA extractable Fe, Cu and
Mn content in soil were decreased with Zn fertilization and the highest content of DTPA
extractable Fe (37.38 mg kg-1), Cu (0.42 mg kg-1) and Mn (9.26 mg kg-1) in soil was
recorded in the control treatment, whereas, the lowest content was found in the treatment
receiving Zn @ 7.5 kg ha-1. Application of 500 ppm ZnO NPs as foliar with soil
application of Zn @ 3.75 kg ha-1 recorded significantly the highest DTPA extractable Zn
content of 1.33 mg kg-1 in the post harvest soil.
The study also revealed that zinc fertilization significantly influenced the grain
and stover yield of maize. Perusal of pooled data indicated that among the zinc
treatments, combined application of 500 ppm ZnO NPs as foliar with soil application of
Zn @ 1.25 kg ha-1 registered the highest grain yield (65.04 q ha-1), stover yield (80.39 q
ha-1) and harvest index (46.95%) in maize- maize sequence.
Zinc fertilization exhibited a significant influence on uptake of major as well as
micronutrients by maize. The highest uptake of nitrogen, potassium, calcium and
magnesium by maize crops were recorded in the treatment receiving soil application of
Zn @ 1.25 kg ha-1 in combination with 500 ppm ZnO NPs as foliar. The highest uptake
of phosphorus by grain (14.81 kg ha-1) and stover (18.22 kg ha-1) was recorded in the
treatment receiving 500 ppm ZnO NPs as foliar whereas, the highest sulphur uptake by
grain (9.95 kg ha-1) and stover (11.72 kg ha-1) was found in the treatment receiving
combined application of 500 ppm ZnO NPs as foliar with soil application of Zn @ 3.75
kg ha-1. Among the micronutrients, the highest uptake of Fe (214.56 g ha-1), Cu (31.99 g
ha-1), Mn (56.33 g ha-1) and Zn (156.36 g ha-1) by maize grain was found in the
treatment receiving combined application of 500 ppm ZnO NPs as foliar with soil
application of Zn @ 1.25 kg ha-1. The highest uptake of Fe (846.24 g ha-1), Cu (45.99 g
ha-1), Mn (248.57 g ha-1) and Zn (279.58 g ha-1) by maize stover was also found in the
same treatment.
Analysis of pooled data indicated that method of zinc fertilization had significant
influence on zinc use efficiency by maize. The highest agronomic efficiency (2382.51
kg kg-1), apparent recovery efficiency (36.88%), zinc utilization efficiency (4067.44 kg
kg-1) and partial factor productivity (16913.19 kg kg-1) was recorded in the treatment
receiving foliar application of 500 ppm ZnO NPs. The highest physiological efficiency
(12816.13 kg kg-1), agro physiological efficiency (7567.77 kg kg-1) was recorded in the
treatment receiving combined application of 500 ppm ZnO NPs as foliar with soil
application of Zn @ 1.25 kg ha-1.
Cost benefit analysis revealed that among different treatment combinations, the
highest gross return (Rs. 1,17,072.00), net return (Rs. 82,773.00) and highest B-C ratio
(2.41) was registered in the treatment receiving 500 ppm ZnO NPs as foliar in
combination with soil application of Zn @ 1.25 kg ha-1. Considering improvement of
crop yield and economic return, combined application of 500 ppm ZnO NPs as foliar
with soil application of Zn @ 1.25 kg ha-1 was found to be superior over other
treatments