Assessment of carbon pools as affected by agricultural land-uses in soils of south-western Punjab
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Date
2017
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Punjab Agricultural University, Ludhiana
Abstract
The present investigation was aimed to study the effect of agricultural land-uses on
organic carbon (OC) content and carbon (C) pools in the south-western plains of Punjab.
Three sites were selected in and around Dhanaula (Site 1) in district Barnala; Bhucho (Site 2)
and Phul (Site 3) in district Bathinda. Three land-uses viz. cropland, horticultural land and
uncultivated land were selected. On an average, all land-uses were more than ten years old. In
all sites, soil pH varied from slightly alkaline to moderately alkaline. Higher EC was observed
in uncultivated and cropland whereas slightly moderate salinity hazard reported particularly
from site 2. Samples were mostly of sandy loam to loamy sand in texture. Uncultivated and
cropland had higher bulk density in all sites. Mostly horticultural land contained higher
available N while available P and K were recorded high in cropland. Zn, Fe and Mn contents
were rated high in horticulture where Cu content was sufficient in almost all sites irrespective
of land-uses. Both water stable aggregates (WSA) and mean weight diameter (MWD) were
recorded highest in horticultural land in all three sites. Horticultural land (9.73 g kg-1) had
highest SOC content. Macro-aggregates (0.25 - > 2 mm) were found to be main carrier of
organic carbon and highest OC was associated with 1-2 mm sized aggregates. At site 1,
horticultural land-use was recorded with highest amount of total particulate organic carbon
(TPOC) (5154.25 mg kg-1), KMnO4-oxidizable C (1295.39 mg kg-1) and cropland was
observed with highest inorganic carbon (IC) (1520 mg kg-1). At site 2, horticultural land was
found to be associated with highest TPOC (4180.34 mg kg-1), KMnO4-C (1442.39 mg kg-1),
mineralizable carbon (MC) (442.8 mg kg-1) and uncultivated land with highest IC (1790 mg
kg-1). Similar to site 2, at site 3, TPOC (3537.01 mg kg-1), KMnO4-C (1805.33 mg kg-1) and
MC (865.6 mg kg-1) were highest in horticultural land whereas IC (1100 mg kg-1) was noted
maximum in cropland at site 3. Significant differences among different land-uses were more
pronounced in surface layer than deeper layers regarding different C fractions. Positive
correlation was reported among different C pools. The potential for C sequestration was
found high in horticultural land-use than other two land-uses.