Chapters authored
Synchrotron Based Techniques in Soil Analysis: A Modern Approach
Soil is a highly heterogenous system where a number of physical, chemical and biological processes are taking place. The study of these processes requires analytical techniques. The electromagnetic radiations in the form spectroscopy, X-Ray diffraction, magnetic resonance etc. have been used in the field of soil analysis since decades. The study of soil nutrients, mineralogy, organic matter and complex compounds in soils use these techniques and are successful tools till date. But these come with a limitation of lesser spatial and spectral resolution, time consuming sample preparation and destructive methods of study which are mostly ex-situ. In contrast to the conventional spectroscopic techniques, the synchrotron facility is of high precision and enables non-destructive study of the samples to a nano scale. The technique uses the high intensity synchrotron radiation which is produced in a special facility, where the electrons are ejected using very high voltage and accelerated in changing magnetic field, at a speed of light resulting in a very bright radiation that enables a very précised study of the subject. For example, in studying the dynamics of P and N in soils, SR aided XAS are used to study the K-edge spectra of these nutrients, without any matrix interference, which used to be a problem in conventional SEM, IR or NMR spectroscopy. These radiations provide high energy in GeV, which imparts high sensitivity and nanoscale detection. Basically, the SR facility improves the precision of the existing spectroscopic techniques. This chapter discusses how the Synchrotron radiations aid to improve precision in various field of soil analysis such as, carbon chemistry, nutrient dynamics, heavy metal and contaminant speciation and rhizosphere study. However, the technique also come with major limitations of requirement of very high skill for preparation of samples, inadequate availability of references for studies related to absorption spectrum and control of radiation damage. Applications and limitations of the technique thoroughly reviewed in this chapter with an aim to provide a brief idea of this new dimension of soil analysis.
Part of the book: Technology in Agriculture