Current Science

K. Rajan ¹, A. Natarajan ², V. Kasthuri Thilagam ¹, K. S. Anil Kumar ², D. Dinesh ¹, N. M. Alam ³, O. P. S. Khola ¹, R. C. Gowda ⁴

Affiliations
1 ICAR-Indian Institute of Soil and Water Conservation, Research Centre, Udhagamandalam 643 004, IN
2 ICAR-National Bureau of Soil Survey and Land Use Planning, Hebbal, Bengaluru 560 024, IN
3 ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun 248 195, IN
4 Department of Soil Science and Agricultural Chemistry, GKVK, University of Agricultural Sciences, Bengaluru 560 065, IN

Abstract

Effect of sodicity on clay dispersion in salt-affected black soils of the Kabini canal command area in Chamrajnagar district, southern Karnataka was studied. Forty-eight soil samples were collected from nine soil profiles and analysed for physical and chemical properties. The clay dispersion ranged from 0.57% to 62.1%. High positive and negative correlations with exchangeable sodium and exchangeable calcium respectively, with clay dispersion were recorded, which can be predicted better with exchangeable sodium and available soil water. Based on clay dispersion value, 2%, 27% and 71% soils are dispersive, intermediate dispersive and non-dispersive respectively. Based on exchangeable sodium percentage, 50, 21 and 29 soils are dispersive, intermediate dispersive and nondispersive respectively. Application of gypsum and organics reduces the clay dispersion in surface soil. Sub-surface drainage will be more effective. Construction of soil and water conservation structures with pile foundation; providing cement lining for soil stabilization in normal construction; providing drainage lines for the structures; construction after refilling with non-dispersive soil will save the structures in salt-affected soils.

Keywords

Clay Dispersion, Sodicity, Sub-Surface Effect, Surface Effect.

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K. Rajan ¹, P. Raja ¹, D. Dinesh ², Sanjeev Kumar ³, B. P. Bhatt ³, U. Surendran ⁴, Deo Karan ⁵, B. P. Bhaskar ⁶

Affiliations
1 ICAR-Indian Institute of Soil and Water Conservation, Research Centre, Udhagamandalam 643 004, IN
2 ICAR-Indian Institute of Soil and Water Conservation, Research Centre, Vasad 388 306, IN
3 ICAR Research Complex for the Eastern Region, PO: Bihar Veterinary College, Patna 800 013, IN
4 Centre for Water Resources Development and Management, Calicut 673 571, IN
5 Krishi Vigyan Kendra, ICAR Research Complex for Eastern Region, Buxar 802 103, IN
6 ICAR-National Bureau of Soil Survey and Land Use Planning, Regional Centre, Bengaluru 560 024, IN

Abstract

Soil potential to store organic carbon was assessed in the hot sub-humid dry Agro-Ecological Region (AER) of the Indo-Gangetic Plains under Recent alluvium of southern Bihar, India. The study was carried out in four prevailing cropping systems, viz. Rice–Wheat– Fallow (R–W–F), Pearl millet–Wheat–Fallow (P–W– F), pigeon pea (monoculture) and vegetable cultivation. Two different recovery factors were used to estimate Total Organic Carbon (TOC), which yielded similar results. The Soil Organic Carbon (SOC) was found highest in pigeon pea-grown soils (69.2 tonnes ha^–1) followed by R–W–F (56.2 tonnes ha^–1) and vegetable cultivation (55.8 tonnes ha^–1). The lowest SOC stock was found with P–W–F (19.2 tonnes ha^–1). The differences in SOC stock between pigeon pea and that of rice–wheat, vegetables and pearl millet–wheat are 13.0, 13.4 and 50.0 t ha^–1 respectively, that are the quantity of organic carbon can be sequestered further in these three land uses from 47.71, 49.12 and 183.50 tonnes of carbon dioxide from the atmosphere respectively. Highly significant positive correlation of soil qualities parameters such as available nitrogen (r² = 0.25), copper (r² = 0.45), zinc (r² = 0.31) and dehydrogenase activity (r² = 0.44) was found with SOC stock under the hot, sub-humid, dry, AER of southern Bihar. Similar assessment can be done in any AER and the potential of soils can be identified to increase carbon sequestration from the atmosphere.

Keywords

Agro-Ecological Region, Cropping Systems, Organic Carbon Stock, Recent Alluvium, Soil Quality.

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