Optimizing mixtures for producing biosolid soilless sod over plastic

The simplex lattice design was used to optimize the mixtures for producing biosolid soilless sod over plastic by using coal cinder, mushroom mulch, and sand. The nutrients, heavy metals content, bermudagrass growth and integrated turf quality of 11 mixtures were analyzed over plastic with method of grey correlation coefficient by establishing the correlative regression model between the turf integrated qualities and mixing ingredients. The results of this study indicated than the chlorophyll content kept stable but above and underground biomass, sod weight, root activity, density, establishment rate, and sodforming rate were significantly different. The optimal mixture was that the content of biosolid, coal cinder, mushroom mulch and sand were 51.41% to 51.83%, 18.32% to 18.86%, 18.19% to 18.81% and 10.87% to 11.72%, respectively. The turfgrass plant enriched heavy metals and the heavy metal content decreased when turf was harvest, and the heavy metal of which conformed to national farmland environmental quality evaluation standards.