Formulation Optimization of Soilless Culture Substrate by Using Uniform Mixture Design Method

Purpose In recent years, the demand for high-quality agricultural products has been increasing, and the soilless substrate production has been expanding in agricultural field with the deepening awareness of food safety. Peat has been widely used all over the world in recent decades as the main material of the traditional substrate, but the peat source is decreasing and even exhausted because of its non-renewable, high priced, and environmental protection requirements. Therefore, it is of great practical significance to study the new matrix synthetic materials in whole or in part to replace the peat substrate, and to develop new soilless culture substrates.

Method We selected several organic materials including bagasse, medicinal herb residue and lignite. The above three materials were mixed together with perlite and peat by different proportion, and then made into ten mixture substrates by using the method of uniform mixture design. The ten mixture substrates were carried out on cabbage breeding and cultivation experiment. In this study, the germination rate, seedling rate, fresh weight, yield and value to cost ratio (VCR) were measured, and the data was simulated with the proportion of materials by regression model.

Result Different mixture substrates had significant effects on the germination rate, seedling rate, agronomic traits, yield and VCR (P<0.05). The most optimal formulations of seedling rate, yield, and VCR wereφ(bagasse):φ(medicinal herb residue):φ(lignite):φ(peat):φ(perlite)=1.27%:26.76%:13.49%:4.14%:54.33%; 52.71%:1.39%:1.66%: 42.26%:1.98%;7.18%:1.39%:66.03%:21.60%:3.80%, respectively.

Conclusion (1) The uniform mixture Design method can be used to select the optimal formula from a variety of raw materials with high efficiency and accuracy. (2) Reduced cost and increased output was achieved by replacing peat partly from bagasse or lignite.