Nuclear Research Laboratory, Indian Agricultural Research Institute, New Delhi, 110012.
The influence of complex forming components on the properties of natural complexes isolated from Vertisols were investigated. The highest concentration of organic carbon (16.4 g kg−1) was observed in clay size fraction of natural complexfollowed by 2–20 μm (16.1 g kg−1) and 20–50 μm fraction (11.4 g kg−1). The organic component of the complex imparted higher exchange capacity, higher surface area, lower phosphate and potassium fixation capacity. The sesquioxides and allophanes also had their share in overall exchange capacity, surface area and P and K fixation capacity of complexes. The X-ray diffraction analysis (XRD) and transmission electron microscopic (TEM) observations revealed that, the clay-organic complexes were of surface adsOrbed type, while differential thermal analysis (DTA) data indicated both surface adsorbed and interlayer complexes.
Clay-organic complex, X-ray diffraction, differential thermal analysis, transmission electron microscopy
