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Water retention in hydrogel substrates: influence of the material characteristics and the fertilizing level

Abstract

Considering that the substrates have different physical and chemical constitutions and that the release of ions from the substrate or the addition of fertilizers increases the electrical conductivity of the solution, the objective of this work was to evaluate the water retention in substrates with hydrogel, without and with fertilization. The experimental design used was a completely randomized, in a 4 x 3 x 2 factorial scheme, with four replications. The factors consisted of four substrates (composted pine bark, coconut powder (crushed mesocarp fiber), Sphagnum peat and commercial substrate (based on Sphagnum peat, expanded vermiculite, roasted rice husk, dolomitic limestone and plaster), three forms of application of the hydrogel product (without application, with application without pre-hydration and with application after hydration) and two ways of applying the basic fertilization (present and absent) .The hydrogel used was a potassium polyacrylate copolymer (K2S2O8). The results show that the addition of hydrogel promotes improvements in the water retention capacity of the substrates However, it is influenced by its composition and by the presence of chemical fertilizers. The higher the EC of the substrate, the lower the hydration potential of the hydrogel. The hydrogel application method, whether dry or pre-hydrated, does not influence the water retention capacity by the substrates. The hydrogel applied to the substrate once dehydrated, maintains its ability to rehydrate.

Keywords:
Electric conductivity; Fertilization; Water retainer

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