Impact of wood fiber substrate additions on water capture through surface and subsurface irrigation

B.A. Schulker, B.E. Jackson
The effectiveness of a horticultural substrate to imbibe water through irrigation can be part of a sustainable plant production program. A reduction in substrate wettability can lead to lower water capture, excessive leachate, and poor plant growth. The movement toward new soilless substrate materials in plant production is necessary for a sustainable future in plant production. To better understand the impact of these materials on water imbibition, Canadian sphagnum peat moss was amended with a hammermilled pine tree substrate (PTS) at ratios of 20, 40, and 60% before undergoing both surface and subsurface irrigation evaluations to study the impact of PTS additions on substrate water capture. Using both an ebb and flood subirrigaton unit and the NCSU overhead wettability method, we investigated the capillary capture intensity and gravitational capture intensity by using volumetric water content curves to identify the plateau where water uptake was maximized under 50% moisture contents. Under surface irrigation, the increasing wood content increased the amount of water imbibed by the substrate over 10 irrigation events, while also increasing the speed at which water was captured. Through subsurface irrigation, there was less of an impact on total imbibition. Water content within the substrate increased at the first irrigation event as wood ratio increased, showing that the wood content aided in reducing the hydrophobicity of peat. By the 10th irrigation event, the differences were insignificant, all capturing similar amounts of water. This shows that under greenhouse irrigation conditions, the increase of PTS in sphagnum peat moss does not decrease the amount of water captured but does increase the flow of water through the substrate, allowing more water to be captured over multiple events.
Schulker, B.A. and Jackson, B.E. (2023). Impact of wood fiber substrate additions on water capture through surface and subsurface irrigation. Acta Hortic. 1377, 597-604
DOI: 10.17660/ActaHortic.2023.1377.74
https://doi.org/10.17660/ActaHortic.2023.1377.74
capillary, water capture, soilless media, irrigation, sphagnum peat
English

Acta Horticulturae