Volume 19 Part 1 Article 35
Title: The use of corn stover to replace straw in compost formulations for the production of Agaricus bisporus
Author: John A Pecchia, David M Beyer and Xiao Li
The first step in the production of the button mushroom, Agaricus bisporus, is Phase I composting. Phase I composting is a high-temperature biological and chemical process needed to prepare and modify the raw materials for the introduction of A. bisporus mycelium, in the form of spawn. The main objectives of Phase I composting are to prepare a homogenous, high moisture mixture that forms a complex lignocellulosic and selective substrate that is used as a food source for A. bisporus. The raw materials that are utilized in formulating this mix vary throughout the world, based on availability and costs. The basic formula that is most widely adopted in Western production systems consists, at a minimum, of wheat straw or wheat straw-bedded horse manure, poultry manure and gypsum (calcium sulfate). In the eastern part of North America, mulch hay is used in large quantities to replace straw due to its availability and relatively low costs. Other nitrogen sources (meals and inorganic fertilizers) can be used in place of or as a supplement to poultry manure based on costs and availability. Other carbohydrate materials (corn cobs, cottonseed hulls, leaves, etc.) can also be supplemented to these straw or hay-based formulations. Corn stover, the plant material left in the field after the harvest of the grain kernel, is a raw material that is relatively abundant in regions that produce corn and can be used to supplement the formulation as well. Previous, unpublished work has demonstrated that corn stover can be used up to 20 percent of the formulation without any adverse impact on mushroom yield. A challenge to producing affordable mushroom substrate in some regions is a limited supply of straw, whether wheat or rice straw. Cropping experiments were conducted at the Pennsylvania State University Mushroom Research Center to determine if corn stover could be used at 50% and 100% of the bulk raw material in the Phase I compost formulation to produce a high yielding A. bisporus crop. Results showed that, when composted properly, mushroom yields grown on both 50 and 100% corn stover formulations yielded as high as traditional straw-based compost formulations. These results suggest that corn stover can be used in place of straw to produce A. bisporus compost in regions that have limited or no economically affordable straw supplies.