Assessing cation exchange capacity (CEC) in old alluvium soils (Agro-climatic zone IIIB of Bihar) under Different tillage and management practices

Abstract

To assess cation exchange capacity (CEC) under different tillage and management practice, a laboratory experiment was carried out at IARI, Pusa, New Delhi. The soils samples varying in depth 0-15, 15-30, 30-45 and 45-60 cm were collected from all the three replications of four different treatments (scenarios) and one uncultivated site of conservation agriculture field of Cereal System Initiative for South Asia (CSISA) project, Indian Council of Agricultural Research Complex for the Eastern Region (ICAR-RCER) in Patna, Bihar, India. The experimental soil is non-calcareous non saline old alluvium with silty clay texture and above neutral pH and the climate of the experimental site is sub humid with average annual rainfall of 1130 mm. Cation exchange capacity (CEC) in cmol (p+) kg-1 of the old alluvium soils was found lower (36.59 cmol (p+) kg-1) in surface soils (0-15 cm) than sub-surface soils (15-30 cm).This might be due to migration of fine clay-humus particles especially in puddled soils i.e. farmers practices in rice-fallow-wheat cropping system with puddled rice and conventional tillage wheat without crop residue (FP in R-F-W) and partial conservation agriculture practices in rice-wheat-mungbean cropping system with puddle rice, zero till wheat and conventional tillage mungbean and partially (anchored) incorporated rice and wheat residue and fully incorporated Mungbean (PCA in R-W-M). Among the treatments highest CEC of 43.81 cmol(p+) kg-1 CEC was found in farmers practice soil (FP in R-F-W) followed by PCA in R-W-M having CEC of 39.95cmol(p+) kg-1 and the lowest CEC of 33.14 was found in uncultivated soils (US).