Original aticle December 2013  Volume 26  Issue 2 78 Indian Journal of Hill Farming Indian Journal of Hill Farming 26(2):78-83 Available online at www.kiran.nic.in Analogy of Soil Parameters in Particle Size Analysis through Laser Diffraction Techniques ROOMESH KUMAR JENA 1* , R. JAGADEESWARAN 2 , R. SIVASAMY 2 Received November 11, 2013; Revised November 30, 2013; Accepted December 2, 2013 ABSTRACT A study was undertaken to optimize the parameters for particle size analysis through laser diffraction techniques. Fifty soil samples with varying soil texture, organic matter, sesquioxide content and calcareousness were collected and analyzed for soil texture by conventional (International Pipette Method-IPm) and Instrumental (Particle Size Analyser-PSA) methods. The study reveals that PSA is more accurate and preferable compared to IPm in determining the soil particle sizes. The clay content of the different samples estimated by International Pipette method and by Particle size analyzer varied from 0.9 to 48.4% and 0.35 to 41.2 %, respectively. PSA showed a good agreement (72% samples) for silt size fractions, and a slight shift in the upper limit of clay from conventional size of 2 μm could help in analysis of soil texture by PSA. Keywords: Soil texture, international pipette method, particle size analyser INTRODUCTION Soil texture is a qualitative classification tool used in both field and laboratory to determine classes for agricultural soils. The classes are distinguished in the field by the ‘textural feel’ which can be further clarified by separating the relative proportions of sand, silt and clay using grading sieves. The class is then used to determine crop suitability and to approximate the soil’ s responses to irrigation and management practices. Traditional particle size determination techniques include sieves for the larger size ranges, usually above 63μm (230 mesh size). Sieves are limited in resolution (number of sieves = number of data channels), they are slow and operator intensive, and has limitation for determining the smaller size classes. Pipette or sedimentation method is generally used for the finer fractions; however, this technique is slow and is affected by particle shape. Modern automated analytical techniques are used for sizing sediments which includes laser diffraction and digital image processing. They are fast, easy, operator independent, have a much broader range and higher resolution with many more data channels. In these techniques, particles are to be independently suspended in the flow-cell and the desirable condition is achieved by agitation and ultrasonification whereas the chemical means of removing cementation is not followed. Laser Diffraction techniques are occasionally applied to soil material (Cooper et al. 1984). Laser Diffraction Technique measures light scattered from the particles suspended in the measurement cell. The angle of scatter is related to the size of the particles. The measurement is essentially instantaneous, although total analysis times are in the order of 30 seconds for most samples. The instrument is popular for this application because of its wide size range (0.02-2000 μm), speed, stability and ease of use. With this background, the present investigation was attempted to study the variability and relationship between the international pipette method and laser diffraction technique for varying soil properties. 1 NBSS&LUP, Regional Centre, Jorhat, Assam 2 Department of Remote Sensing and GIS, Tamil Nadu Agricultural University, Coimbatore-641003 * Corresponding author ’ s Email : roomeshjena@gmail.com