Effects of Spent Mushroom Compost (SMC) Application on Some Chemical Properties of A Sandy Loam Soil and Leachate

Waste produced from mushroom production industry, including the mushroom production substrate, has the necessary properties and potentials for use as a soil amendment in agricultural farms. These wastes, known as Spent Mushroom Compost (SMC), are normally disposed of after production process of mushroom. The aim of this research was to study and compare the effects of various SMC's (fresh, one year old, and two years old) at different levels of application (15, 30 and 60 t.ha-1) on the chemical properties of a sandy loam soil. Different SMC treatments were mixed into soil columns and, during a 12-week period in laboratory incubation conditions, they were weekly leached by distilled water. The leachates from the columns were collected at the end of the 1st, 4th, 8th, and the 12th week and analyzed for EC, pH, soluble cations (sodium, potassium, calcium, magnesium) and anions (chloride, bicarbonate, nitrate). Similar analyses were conducted on the soil samples at the start and at the end of the experiment. The results of leachates and soil samples analyses showed that EC in the two-year-old SMC was the lowest, but the amounts of ‍‍‍calcium and magnesium were the highest. The two- year-old SMC that had higher nitrate content than the other two SMC's lowered Cl and Na of the soil samples; therefore, it can probably provide some of the nutrient requirement of plants. Comparison of different levels of SMC showed that use of 30 ton ha-1 was more favorable. The 60 ton ha-1 level caused higher EC and salinity. Considering the high nutrient content of SMC, if this material is used in a suitable amount, it could improve soil chemical properties.