Low cost measurement of moisture content in long grain paddy

Abstract

A method was proposed and assessed for measuring the moisture content of paddy using a moisture inspection card. The effects were investigated of the head space, testing duration and moisture content of paddy on cobalt chloride-coated paper discoloration. The coated paper production process consisted of soaking paper in a solution of cobalt (II) chloride and methyl alcohol and then drying at 60 °C. The experiments using the paddy and coated paper were carried out in a jar with the head space of 25%, 50% or 75%, with the lid closed for 30 or 45 min. The results of the experiment to measure the change of the coated paper in the paddy with moisture content of 10–24% wb showed that the paper color slowly changed from blue to pink with an increase in the moisture content. Evaluation using the CIE color system found that the color value from experiments with a head space of 75% for 30 min was not significantly different from that used with a head space of 50% or 25% for 45 min, though for all head space levels, testing duration of 45 min there was more color than for 30 min with the different moisture contents of paddy. Hence, using a head space of 75% for 45 min produced significantly highest color value, so these conditions would be sufficient to allow the paddy moisture content to equilibrate with the relative humidity in the head space. The L∗, a∗, and b∗ values of the coated paper were converted to RGB values for color image printing to subsequently produce a moisture inspection card, based on the color change of the coated paper. In addition, the moisture inspection card is low cost could be reused, so it would be suitable for use by farmers in rural areas. • This method was very cheap price and can be reused. • Suitable for use by farmers in rural areas and small scale farms. • Preliminary examination of how much moisture content of paddy before deciding to sell.