Measurement of Absolute and Relative Water Content of Plant Leaves using Beta Radiation

This paper presents the estimation of absolute and relative water content (WC) in the leaves of various crops grown at Punjab Agricultural University, Ludhiana, India, using the beta radiation attenuation method (from 204Tl). Experiments were conducted to measure the water content in the leaves of brinjal, pumpkin, spinach, tomato, mung bean, sunflower, and cotton. The mass attenuation coefficient (μm) was utilized to evaluate the WC, revealing that it is higher for dry leaves compared to fresh leaves. The water content percentages determined using the β-radiation attenuation method were found to differ by a maximum of approximately 5% from those obtained by direct weighing. The water content percentages were nearly identical for brinjal, sunflower, and cotton, with a difference of within ± 1σ, as well as for spinach, tomato, and mung bean leaves within ± 1σ. The largest discrepancy in water content was observed between mung bean leaves and pumpkin leaves, with a difference of approximately 23.1%, suggesting a lower organic matter content in mung bean leaves compared to pumpkin leaves. This technique provides valuable insights into the water status of plants and is fast, accurate, and easy to handle, making it an effective tool for determining water content and advancing precise agricultural technologies.