Providing food for the growing global population is one of the main concerns of human society. In the last decades, huge amounts of chemical fertilizers, particularly nitrogen fertilizers, have been applied in Iran but the importance of organic amendments has been neglected. Excessive use of chemical fertilizers has caused waste of resources and environmental pollution; therefore, a need for application of organic amendments in farmlands has been arisen. Composting is one of the effective methods for transforming organic wastes and plant residues to soil amendments. Compost is a result of organic wastes biodegradation by different types of microorganisms under controlled conditions. Medicinal plant wastes are a group of organic wastes that are produced in large quantities in Iran. Converting these wastes into composts and using of them as organic fertilizers can improve soil physical, chemical and biological properties in dry regions of Iran. Hence, this study was performed to investigate the effect of composts made from myrtle ( Myrtus communis ) and mint ( Mentha suaveolens ) wastes on soil chemical properties and growth indices of corn ( Zea mays L.). For this purpose, a factorial pot experiment in a completely randomized design was set up in a greenhouse. The medicinal plants wastes were obtained from Barij Essence Pharma Co, Iran and composted during a 90 day period under controlled temperature and moisture conditions. The matured composts were mixed with the soil at four levels (0, 2, 4 and 8 percent) and transferred to 2.5-kg pots with three replications. Then, five seeds of corn (single cross 704) were sown in each pot and thin to three seedlings after germination. After a 60 day plant growth period, the aerial parts of the plants were harvested, over-dried, powdered, and used for further analyses. Soil samples were also collected from each pot, air-dried and used for laboratory chemical analyses. The results showed that the compost produced from myrtle wastes can be Keywords: Organic fertilizer, Organic waste, Compost, Organic amendment, Myrtle, Mint.
