Impact of cropping systems on the potential of carbon stock in soils of Western Haryana
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Date
2017
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CCSHAU
Abstract
Increasing carbon stock in agricultural soils is essential to achieve food security and environmental
quality. An understanding of the dynamics of soil organic carbon as affected by farming practices is
imperative for maintaining the soil productivity and management of soil organic carbon pools is
important for sustainable agriculture. Excessive use of chemical fertilizers and meager use of organic
sources of plant nutrients, crop residues and adoption of exhaustive crops have resulted in depletion of
available nutrients in soils of Haryana. Soils in the state have potential to sequester carbon to a variable
magnitude depending upon their texture. Surface and sub-surface soil samples collected with the help
of GPS across Sirsa, Hisar, Fatehabad, Bhiwani, Mahendragarh, Rewari, Jhajjar and Jind districts of the
Haryana State were analysed for various properties. The soil organic carbon (SOC) (3.51 g kg-1), soil
organic stock (SCS) (8.63 Mg ha-1 C) and carbon sequestraion rate (0.86 Mg ha-1 C) were significantly
higher under rice-wheat cropping system as compared to cotton-wheat, pearl millet-wheat, pearl milletmustard,
pulses-wheat, fallow-mustrad, fallow-gram and vegetables-vegetables cropping systems.
However, the improvement in SOC to the tune of 30 to 75% was observed in the soils under rice-wheat
than other cropping systems. Likewise, the Microbial biomass carbon (MBC) (85.3 mg kg-1), light
carbon fraction (LCF) (0.31 g kg-1), heavy carbon fraction (HCF) (0.98 g kg-1), coarse particulate
organic carbon (cPOC) (0.28 g kg-1), fine particulate organic carbon (fPOC) (0.47 g kg-1), mineral
associated organic carbon (MOC) (1.31 g kg-1) and dehydrogenase activity (DH) (12.16 μgTPF/g
soil/24 h) were also significantly higher under rice-wheat cropping system. Soils under rice-wheat
system were having significantly higher SOC (2.54-3.11 g kg-1), SCS (6.64-7.25 Mg ha-1 C), SCR
(0.66-0.73 Mg ha-1 C) and organic pools of MBC (58.6-74.6), LCF (0.21-0.24 g kg-1), HCF (0.65-0.83
g kg-1), cPOC (0.19-0.22), fPOC (0.32-0.36 g kg-1), MOC (0.98-1.27 g kg-1) and dehydrogenase
activity (7.03-8.97 μgTPF/g soil/24 h) as compared to their adjoining uncultivated soils. At various soil
profile depths, the SOC (4.70 g kg-1), SCS (10.21 Mg ha-1 C), SCR (1.02 Mg ha-1 C), and organic pools
of MBC (99.4 mg kg-1), LCF (0.40 g kg-1), HCF (1.23 g kg-1), cPOC (0.37 g kg-1), fPOC (0.55 g kg-1)
and MOC (1.88 g kg-1) were significantly higher at surface 0-15 cm depth as compare to deeper soil
depths. Soil physical and chemical properties had significant influence on soil organic carbon status of
the soils. Bulk density (1.50 Mg m-3), pH (7.71), electrical conductivity (0.56 dS m-1) were higher at
60-90 cm soil depth, and nitrogen (117 kg ha-1), phosphorus (15.7 kg ha1), potassium (104 kg ha-1) and
sulphur (20.2 mg kg-1) were significantly higher in surface 0-15 cm soil depth under rice-wheat than
other cropping systems. Relationship between SOC to SCS, SOC to carbon pools and SOC to available
nutrients was found positively and significantly correlated. Soils under rice-wheat system have less
potential to store carbon as compared to other cropping systems.