Artificial Manure for Mushroom Production

Abstract

For the commercial production of mushrooms, horse manure, properly composted, was found to be, up until the present time, the only important substrate. All attempts to develop a compost from plant residues and inorganic fertilizer, without the aid of the digestive system of the horse, have so far given rather unsatisfactory commercial results, although the feasibleness of such a process has been definitely established (1-4). Horse manure contains about 70 to 80 per cent moisture and about 2 per cent of nitrogen, on a dry basis; a part of this nitrogen is in a water soluble form, largely as urea and ammonia, and a part in an insoluble form, largely as protein. When horse ma? nure is placed in composts and allowed to undergo aerobic decomposition, four distinct processes are found to take place (5, 7) : (1) a gradual decomposition of the carbohydrates comprising the two major groups of these complexes present in the manure, namely, the cellulose and hemicelluloses; (2) a rapid transformation of the water soluble forms of nitrogen in the manure into insoluble organic nitrogenous compounds, accompanied by an increase in the relative total nitrogen content, because of the reduc? tion of the total dry matter in the manure; (3) an increase in the relative content of the lignin and its derivatives, which resist rapid decomposition by the microorganisms active in the compost; (4) an increase in the relative ash content of the compost, parallel to the reduction of total dry matter, due to the accumulation of the mineral constituents in the process of decomposition; if no other data are available, one can measure the loss of total organic matter as a result of decomposition by the increase in ash concentration. When the total quantity of material in the compost has been re-