PHYSICAL AND HYDRAULIC PROPERTIES OF FOUR SUBSTRATES USED IN THE CUT-FLOWER INDUSTRY IN COLOMBIA

The know-how regarding the substrates physical characteristics and water management is too empirical, and few reports are found on the type of substrates used in Colombia.
This paper studies the hydro-physical properties of four substrates used in Colombia cut-flower industry: 1) 100% burnt rice husks; 2) mixture of 65% burnt rice husks and 35% coconut fiber (mixture 1); 3) mixture of 35% burnt rice husks and 65% coconut fiber (mixture 2); and 4) 100% coconut fiber.
The results showed the particle size distribution for coconut fiber and the mixture 2 follow a unimodal distribution while the burnt rice husks and mixture 1 presented a multimodal one.
Values obtained for solid density were 1, 0.9, 0.6 and 0.5 for burnt rice husks, mixtures 1, 2 and coconut fiber, respectively.
Those values are lower than those reported in the literature.
The average values of bulk density for burnt rice husks had 0.29 g cm^-3, whereas mixture 1, mixture 2 and coconut fiber had 0.18, 0.17 and 0.13 g cm^-3 respectively.
The water retention curves were fitted to the Van Genuchten model.
The highest water retention between 1 and 10 kPa was obtained for the burnt rice husks.
The volumetric water content was: 24.1%, 22.1%, 18.9% and 13.6% for burnt rice husks, mixture 1, mixture 2 and coconut fiber substrates respectively.

III International Symposium on Models for Plant Growth, Environmental Control and Farm Management in Protected Cultivation (HortiModel 2006)

M.F. Quintero, C.A. Gonzalez, V.J. Florez-Roncancio

particle size distribution, water retention curve, bulk density, rice husks, coconut fiber

https://doi.org/10.17660/ActaHortic.2006.718.58