Use of Peanut Shell Compost in Growth Media and Its Effect on the Physical and Chemical Properties of Soil

< p >Peanut shell as a residual waste from peanut cultivation has a considerable volume and its compost can be used as an available source of nutrient elements for different plants. This study was carried out to investigate the use of peanut shell compost in field soil and soilless (peat-perlite ratio 2: 1) media and its effect on soil physical and chemical properties in Lahijan Ornamental Flower and Plant Research Station, in 2017. Control treatments consisted of field soil and peat-perlite (2:1) bedding, while peanut shell compost was used in values of 0, 25%, 50%, 75%, and 100% (by volume) to replace field soil and peat (2:1) in peat-perlite bedding. This study was conducted as a factorial experiment with two variables (type of media and compost levels) based on randomized complete block design with three replications using violet research model plant (Viola spp < /em>.). At the end of the experiment, physical properties of the substrates including total porosity, air fill porosity, water capacity, bulk density, and  nuterients content of the substrates including Ca, N, OC, P, K, Fe, Zn, Mn, Cu, and also pH and EC were measured. In soilless culture, application of 50% peanut compost (1 peat+1 perlite+1 compost), and in soil media, application of 75% peanut compost showed the best results for the research model plant. Peanut shell compost appears to have better results by reducing C/N ratios and increasing porosity and nutrient supply in these two substrates. Thus, peanut shell compost can be used to replace the expensive peats as well as improving soil properties for cultivation of this ornamental plant.