Soil Humic and Fulvic Acid Fractions Under Different Land Use Systems
-
Author:Sharan Bhoopal Reddy, M.S. Nagaraja, T.S.Punith Raj,Prabhudev Dhumgond and N.S. Vignesh
p-ISSN:0024-9602, e-ISSN:2582-5321, Vol:99, Issue:jul-sep
DOI: https://doi.org/10.29321/MAJ.10.100126
Abstract
Soil organic matter (SOM) in any agro-ecosystem is regulated by interaction of factors that
determine its formation and promote decomposition, with a relative importance as:
management > climate > biota > topography = parent material > time. Different land use
practices under diverse climatic conditions in Hassan district (Karnataka) were selected for
the study. Land use systems receiving frequent biomass additions through litter viz., Forest
systems (both natural and manmade) and coffee plantations were observed with surface
organic layer with higher SOC (10.6-13.2) content (g kg -1 soil). Agricultural systems mainly
paddy, potato, vegetable, coconut and mulberry systems sparse OM additions were observed
with reduced and lower SOC status (4.6-6.6). Humic acid (HA) and fulvic acid (FA) under these
land use systems were dependent on land management i.e. source, form, amount, rate of
organic materials added to soil. The HA fraction ranged from 0.2 g 100 g-1 soil in soils of
coconut and paddy systems to 0.4 g 100 g-1 soil in natural forests. Quantitatively higher HA in
forest and coffee systems was observed than agricultural systems. Proportionately to total
SOM content (%), the HA was higher in agricultural soils (24.4-28.0) than coffee and forest
soils (19.6-20.7). The systems with tree vegetations (forests and coffee) recorded higher
proportions of FA (29.4-30.5) than agricultural systems like potato (26.5) and paddy (27.4).
Forest systems with litter biomass additions (fresh organic materials) were with higher FA
content while, agricultural systems receiving with almost decomposed OM (FYM) indicated
higher HA than FA.
Key words : Land use system, soil organic matter, humic acid, fulvic acid.