Continuous Monitoring of Moisture in Round Modules during Open Storage

The use of the new round module builder pickers has grown very quickly in Australia, reaching about 90% in 2015. As the round module is wrapped by plastic film, concern has been expressed by cotton gins that the moisture content of the round modules may be higher than expected, resulting in increased drying cost and potential impacts on fibre quality.

We used a continuous module monitoring system which includes a temperature & humidity sensor connected by cable to a datalogger. The sensor is inserted into the middle of the round module using special hand tools. Relative humidity (RH) and temperature inside the module are recorded in the datalogger every 15 to 30 minutes for up to eight months without intervention. This gives us the full history of a round module from harvesting to ginning.

The temperature and relative humidity at the top part of the round module fluctuates significantly while conditions in rest of the module were very stable. After a long period of storage, the top part of the module dries out and the bottom part becomes the wettest region. Covering the modules by a tarpaulin significantly reduces the fluctuation of temperature and relative humidity and slows down the drying of cotton at the top part of the module. The orientation of modules during storage has an influence on the conditions of the modules. Core temperatures of modules stored with axis in North-South direction were about 2˚C higher than those stored in the East-West direction during the hot months of the year.

Several cotton quality attributes (length uniformity, strength and colour) displayed statistically significant changes between modules ginned at the beginning of trial and that ginned at the end of storage period.