Characterizing Air and Water Content of Soilless Substates to Optimize Root Growth

Arguedas, F. R., Lea-Cox, J. D., and Ristvey, A. G. International Plant Propagators' Society, combined proceedings 2007, 57:701-708. 2008.

The physical properties of soilless substrates should be well characterized, since it is well-known that it is the ratio of air:water that most influences root growth, and overall plant growth in container production. However, other factors such as container height, geometry, and substrate handling can also have a profound effect on these variables. We tested the performance of Ech2 O capacitance sensors and their ability to accurately monitor water content in a range of soilless substrates with differing physical properties. Desorption curves were generated for each substrate with simultaneous readings, using 5-cm and 20-cm sensors and a custom-built desorption table. The precision of these sensors was confirmed with all soilless substrates tested, although the results revealed that a surprising amount of the total water in these substrates was beyond the commonly accepted range of readily-available water for plants in containers. We are now confident that we can use these sensors, to more precisely schedule irrigation water applications, using the desorption curves from the data we derived in these studies.

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Author(s): F. R. Arguedas, John D. Lea-Cox, Andrew G. Ristvey

Section: Soil Management and Growing Media