Nitrogen is a limiting component and can be increased by changes in the compost formulation and also by the use of supplements. While nutritional supplements are used widely in the mushroom industry, it is not fully understood what nutrition is optimal or how supplements perform on Phase III compost.
HDC has commissioned a twoyear project to investigate the effect of different supplement types on mushroom growth, yield and quality produced on Phase III compost. The project aims to understand how mushrooms obtain nutrition from compost.
The first year focused on evaluating the effects of four different types of supplements on mushroom production. Protein-based, lipid and protein-based, carboxylic acid-based and mineral micronutrient supplements were investigated and their effects on compost temperatures. Supplementation of Phase III composts by protein-based supplements increased mushroom yield and mushroom cap density significantly. However, it should be noted the improvement is dependent in part on the characteristics of the compost. Supplementation did not change the dry matter content of the mushrooms and there were no major effects of supplementation on colour.
The effect of supplements on different batches of compost will be investigated further in the second year when molecular techniques will be used to analyse mushroom gene expression.