Recently UMDIS Mushroom Information Agency published the article about critical lack of straw in Spain. Similar situation we see in other countries, for example in Poland where the largest compost yards during last years struggle to find good straw for compost in that amount which is needed.

We tried to offer some alternatives which can be used for compost production instead of straw.

For this reason, we talked to one of the best specialists on compost and mushroom production in Europe and America, Raymond Samp, owner of Agari Culture Mushroom Consulting Services.Raymond Samp earned a Master of Science degree in Microbiology in the US, after University he was a teacher, and then he started career in mushroom industry and now have over 40 years experience. In his career he occupied every position from grower trainee to General Manager of mushroom farms or Group Manager of three farms in England. Raymond have been a cultural advisor or consultant for 30 years, and before that as manager or other senior positions on mushroom farms.  He has published over 100 articles and has provided consulting services on 6 continents and about 20 countries.  Finally he has presented speeches and seminars at many mushroom conferences around the world.

Raymond Samp shares a few theses about straw alternatives with us.

• There are many alternatives to the basic composting raw materials of wheat straw and poultry manure. Many alternative raw materials I have used and instructed upon. Among the wheat straw alternatives are: barley straw, rye straw, rice straw, timothy/orchard grass hay, corn/maize stalks and stover. These things provide structure, but other carbon-based materials can be used to augment such as cottonseed hulls, ground corn cobs, cocoa shells, leaves, etc. Having said that, wheat straw is generally considered the best.
• And regarding nitrogen alternatives to poultry manure, there are also many. I have used many in my career for various reasons.  Some of them are turkey manure, various seed meals (cotton seed, soy, …), waste grains such as distiller’s or brewer’s, inorganic nitrogen such as urea, NH4SO4, etc.
• Nutritionally there must be a carbon source that is high in complex carbohydrates such as cellulose, hemicellulose, and lignin that will provide the energy for the mushroom during the production process. Wheat straw optimally provides that requirement.
• Structurally there must be raw materials that provide porosity for gaseous exchange during the phase I, phase II, phase III, and growing processes. Since the compost must breathe, the raw material must possess and retain enough resilience or structure to allow this to occur. Additionally, the raw materials must be able to absorb moisture and retain that moisture so that the mycelium, and eventually the mushroom, can easily extract it for its own biological processes as well as to expand the sporophore to its maximum capacity.  In a conventional formulation wheat straw provides this capability.
• There are many materials that can produce mushrooms acceptably in the absence of wheat straw and/or poultry manure. Some carbon sources that can be used to provide the complex carbohydrates, structure and water absorptive requirements of a compost raw material are: rye straw, barley straw, oat straw, corn stalks (maize stover), rice straw, sorghum straw, sugar cane bagasse, soybean straw, rape straw, timothy, orchard grass, various hays, and others.
• Some nitrogen sources that can provide the ammonia for driving phase I, phase II, and mushroom production are: a wide variety of seed meals, various distressed seed meals, various whole or crushed seeds, corn gluten meal, brewer’s grain, distillers grain, malt sprouts, feather meal, blood meal, alfalfa seeds, other manures (such as turkey), inorganic nitrogen sources (such as urea, ammonium sulfate, ammonium nitrate, and others.  Still other ingredients have been used to provide carbon and/or nitrogen in specific circumstances.  They are: alfalfa, cornhusks, crushed corn (maize) cobs, cocoa shells, cottonseed hulls, rice hulls, leaves, and others.
• Usage of substitute raw materials must start with proper formulation. Very briefly this can be done by first analyzing the carbon, nitrogen, and moisture contents of any raw material.  Then relative volumes can be determined via carbon/nitrogen ratio calculation and cold start formulation (in terms of percentage nitrogen and kg N/ton of dry straw) to make a “best guess” recipe for starting the composting process from ground zero.  Adjustments to formulation can then be made as required based on performance.  Additionally, pretreatment of a material, method of blending, and timing of addition of substitute raw materials may vary depending on their particular structural or nutritional characteristics.
• The ash content of any raw material is very important as well. Ash is dirt, stones, sand, and any other non-organic materials, which can be considered impurities.  The ash content of a finished compost is essentially what the raw materials possess at the start, only concentrated (plus gypsum, which is necessary).  The initial ash in the raw materials is concentrated because during the composting process we decompose or shrink, all the organic matter ~25-35%, while the ash does not shrink and stays the same.  As such, it concentrates, or accumulates.

Raymond explains that directly or indirectly he used almost all of these materials at one time or another and they have successfully produced mushrooms.  However, it must be understood that those materials can be best referred to as substitutes for the standard materials because they may be lacking in one fundamental characteristic or another. As such they must be handled, modified, blended, or formulated in one way or another to compensate for their inadequacies compared to the standard. Additionally, they may not provide the equal conversion of dry matter to mushroom production as the standard raw materials.

But another concept that Raymond emphasises is that mushroom production should be economically effective, so that if there is no possibility to get (or get on competitive price) wheat straw – your best choice is to try substitutes and try to make the best formulation.

Raymond Samp,

Agari Culture Mushroom Consulting Services

+1 512 353 4679

raymush@yahoo.com / agariculture1@gmail.com