ABSTRACT

The substrate may be sold immediately after removing from the mushroom house (fresh spent mushroom substrate) or it may be placed in windrows and further composted for at least one winter weathered spent mushroom substrate (Beyer, 1999). In the northeastern United States. SMS is an important source of organic material for the turf industry. Spent mushroom substrate has been used by the turf industry to improve soil physical properties; this is as a result for the SMS been tilled into a clay loam subsoil before turf grass establishment (Landschoot et al., 1993) and this resulted in increased water retention, lower bulk density and improved turf cover. A typical composition of spent mushroom substrate fresh from a mushroom house will vary slightly since raw materials and other cultural practices change, each load of fresh spent substrate has a slightly different element and mineral analysis. Sometimes, fresh substrate is placed in fields for at least one winter season and then marketed as weathered mushroom soil. This aged material has slightly different characteristics because the microbial activity in the field will change the composition and texture. The salt content may change during the aging period. The principal problem encountered in use of SMS is high electrical conductivity. This is true both for use as casing and for plant growth.