Effect of Lime, Humic Acid and Moisture Regime on the Availability of Zinc in Alfisol

Sushanta Kumar Naik,Dilip Kumar Das

doi:10.1100/tsw.2007.192

Sushanta Kumar Naik, Dilip Kumar Das

Open Access

https://doi.org/10.1100/tsw.2007.192

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Abstract

Lime and humic acid application can play an important role in the availability of zinc in paddy soils. We conducted laboratory incubation experiments on a rice growing soil (Alfisol) to determine the effect of lime, humic acid and different moisture regimes on the availability of Zn. Addition of half doses of liming material (powdered lime stone) recorded highest values of DTPA-Zn followed by no lime and 100% of lime requirement throughout the incubation period. With the progress of incubation, DTPA-Zn increased slightly during the first week and then decreased thereafter. The highest DTPA-extractable Zn content of 2.85 mg/kg was found in the treatment Zn10 L1/2 at 7 days of incubation, showing 17.3 % increase in DTPA-Zn content over its corresponding treatment of Zn alone (Zn10L0). The DTPA-Zn concentration increased with the application of humic acid compared with no humic acid throughout 35 days of the incubation period and the peak value obtained was 3.12 mg/kg in the treatment Zn10 HA2 at 14 days after incubation, showing 50 % increase in Zn content over its corresponding treatment of Zn alone (Zn10HA0). The application of 0.2% humic acid compared with 0.1% resulted in greater increase in DTPA-Zn concentration in soil application. During the 35 days of incubation, highest values of DTPA-Zn were recorded in soil maintained at saturated compared to water logged conditions. However, under alternate wetting and drying condition the DTPA-Zn content gradually decreased up to 21 days and thereafter increased slowly.

Highlights

Zinc (Zn) undergoes transformation in soils by various mechanisms i.e. sorption by clays, hydrous oxides, organic matter etc., which affect its availability of Zn in soils
The DTPA extractable Zn content were found to be highest in the treatment where Zn was applied at its highest level of 10.0 mg/kg combined with half Lime requirement (LR) of the soil (Zn10 L1/2) at all days of incubation
Lime applied at half LR in presence or absence of Zn to the Alfisol found to be significantly better in maintaining the DTPA extractable Zn in the soil compared to no lime and full LR of soil at various levels of Zn throughout the incubation period

Summary

Introduction

Zinc (Zn) undergoes transformation in soils by various mechanisms i.e. sorption by clays, hydrous oxides, organic matter etc., which affect its availability of Zn in soils. Desorption of Zn into soil solution is controlled by the energy with which it is adsorbed onto the soil colloidal surfaces. This in turn depends on the soil characteristics pH, cation exchange capacity (CEC), the nature and content of the clay, oxides of Fe, Al and Mn, and CaCO3[1]. When soils are submerged the concentrations of most nutrient elements in the soils increases, but this is not true for Zn. In acid soils Zn availability decreases after flooding owing to an increase in pH and the precipitation of Zn(OH). Some of the red and lateritic soils of India have been classified as Alfisol

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Conclusion