Stability and erodibility of some soils of West Bengal in relation to their aggregating agents Manik Dipa, Nandi Ramprosad, Das Shreya, Bandyopadhyay P.K.* Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, 741252, West Bengal *Corresponding author Email: pkbandyopadhyay63@gmail.com
Online published on 23 March, 2021. Abstract Aggregate stability is a measure to evaluate the ease with which soils erode by water and/or wind to predict the capacity of soils to sustain long-term crop production. In the present study, soils of four different agroclimatic zones of West Bengal, viz. terai, new alluvial, red-laterite and coastal saline having two different cropping systems, viz. rice-vegetables and rice-fallow were used to quantify the soil organic and inorganic aggregating agents and to identify the major agents responsible for the aggregate stability as well as the erodibility. Rice-vegetables cropping system showed significantly higher mean weight diameter, geometric mean diameter, aggregate stability and aggregate ratio as compared to rice-fallow system. Soil organic carbon (SOC) was the major organic binding agent ranged from 4.78 to 12.27 g kg−1, followed by polysaccharide (2.03 to 3.96 g kg−1), easily extractable glomalin (0.25 to 0.70 g kg−1) and phenol (0.011 to 0.053 g kg−1), respectively. The Ca2++Mg2+ was the major inorganic binding agent ranged from 0.78 to 3.07 g kg−1, followed by CaCO3 (0.09 to 2.04 g kg−1), Al2O3 (0.09 to 0.52 g kg−1), Fe2O3 (0.08 to 0.32 g kg−1), Na+ (0.10 to 0.34 g kg−1) and phosphate (0.01 to 0.10 g kg−1), respectively. Terai and new alluvial soils possessed higher SOC (11.0 and 10.3 g kg−1) and polysaccharides (3.81 and 3.24 g kg−1). Soils of new alluvial and coastal saline zones produced significantly higher water stable aggregates with SOC and sesquioxides as prime aggregating agents that increased clay flocculation ratio. Soils of red-laterite zone had an increased aggregate diameter with the help of Fe2O3 as primary agents that decreased stability with a plenty of water dispersible clays. Among the total binding agents, the relative abundance of organic and inorganic agents was 77 to 81 and 19 to 23%, respectively, indicating that the binding agents and their tying mechanisms cohere with soil particles to form aggregates depending on the climate, land use and soil environment. Top Keywords Organic carbon, Polysaccharides, Glomalin, Sesquioxide, Aggregates clay flocculation ratio. Top |