Alternative substrates based on green compost in Agave victoria-reginae and Agave striata minima

The aim of this work was to study the use of two composts, obtained from olive mills (OM) and green waste (SV), at the CREA Research Centre for Vegetable and Ornamental Crops in Pescia (PT), as components of the growing substrate on plants of Agave victoria-reginae and Agave striata minima. Substrates containing 30% inert matter in each case and increasing doses of compost (0, 30, 50, 70%) were compared; satisfaction at 100% volume, if necessary, was achieved by adding quantities of peat to the mixture.  The cultivation density was 6 p m-2 for a total of 98 plants. The cultivation lasted 350 days; the plants never showed any symptoms of water stress. The results were statistically analysed. The chemical and physical properties of the growing media were analysed; the vegetative growth of the plants was determined at 350 days. The results showed that plant growth depends on the percentage of compost. The composts used in the preparation of the substrates were not phytotoxic and allowed the plants to grow disease- and weed-free. Due to their physical and chemical characteristics, composts prepared from municipal park and garden waste and solid fractions of mill waste can be considered as partial substitutes for peat.