pH correction in Salix sp. sawdust-perlite mixture used as horticultural growing media in soil less cultivations

摘要

Salix sp. sawdust is used as growing media in soil less cultivations at Santa Fe (Argentina). However, its pH, as well as that of its mixture with perlite, is higher than the suggested for soil less crops. The aim of this work was to evaluate pH correction and its persistence in Salix sp. sawdust-perlite mixture substrates. Sulphur 1 percent w/w, ferrous sulphate 1 percent w/w and sphagnum peat (pH 5.67) 10 percent v/v replacing equal amounts of perlite were evaluated as pH correctors. Salix sp. sawdust-perlite, 1:1 (v/v) mixture was used as control. pH and electrical conductivity in the drainage solution were measured to evaluate pH correction and pH persistence. Samples from each treatment were placed in a glass column and daily irrigated with nutrient solution. In another trial, perlite was replaced by different levels of peat and the pH response was evaluated. It was observed that the pH correction obtained through the addition of mineral substances was not adequately persistent due to the rapid washing of the minerals. However, incorporation of 10 percent sphagnum peat replacing perlite allowed an optimum and stable pH to be reached for most of the soil less cultivations.