Measurement of acoustical parameters of organic fertilizer urea at various temperatures

Abstract

Synthetic fertilizers are commonly used for growing all crops, with application rates depending on the soil fertility. Urea is an example of a synthetic organic fertilizer, an organic substance manufactured from inorganic materials. Organic fertilizers have been known to improve biodiversity, and long term productivity of soil, and may prove a large depository for excess carbon dioxide. Urea fertilizer provides nitrogen, which promotes green leafy growth. Urea has the highest nitrogen content, equal to 46% and it can be used for all types of crops and soils 1 . The investigation based on the behavior of propagation of ultrasonic waves in fertilizer system are now rather well established as an effective means for examine certain physical properties of the materials. Ultrasonic velocity, density and viscosity values for the fertilizer urea are found in the concentration range of 0.3m to 2.1m at various temperatures from 308˚K to 323˚K. The values of acoustical and thermodynamical parameters such as adiabatic compressibility, acoustic impedance, relaxation time, molal hydration number, free length, apparent molal volume, and apparent molal compressibility are determined. Their variation with concentration is useful in understanding the nature of molecular interaction in terms of physical parameters. These results were confirmed by soil test. A soil test gives the information about the availability and lack of nutrients in the soil. The quantity of available nutrients in the sample determines the amount of fertilizers that is recommended for a particular crop. This is also confirmed by the values of 3-4 . The ultrasonic velocity and density of urea fertilizer at different temperatures have been reported in the present paper. From these experimental data, the number of acoustical and thermodynamic parameters like specific acoustic impedance (z), intermolecular free length (Lf), relaxation time ( τ ) hydration number (nh) , apparent molal compressibility (φk), apparent molal volume (φv), have been calculated. The values of the parameters have been used to interpret various molecular interactions occurring in the solutions at different temperatures and concentrations of urea.