Effects of Different Exogenous Nutrient Bag Formulations on the Agronomic Traits, Nutritional Quality, and Soil Ecological Environment of Morchella sextelata

Exogenous nutrient bags are essential for the artificial cultivation of Morchella sextelata, but the effects of different formulations on yield, nutritional quality, and the soil microecological environment remain unclear. In this study, nine exogenous nutrient bag formulations and one conventional treatment (CK) were evaluated during M. sextelata cultivation. Fruiting time, fresh and dry yields, and nutritional quality indicators were measured, and principal component analysis combined with membership function analysis was used for comprehensive evaluation. Soil physicochemical properties were determined for all treatments, and A7, A3, and CK were selected to represent the best-performing, worst-performing, and conventional treatments, respectively, for soil microbial community analysis. Different formulations significantly affected agronomic and nutritional traits (p < 0.01). A6 showed the shortest fruiting time and the highest fresh and dry yields, whereas A7 had the highest polysaccharide content and ranked first in the comprehensive evaluation. The D values of A7, A6, and CK were 0.789, 0.777, and 0.653, respectively. Soil nutrient analysis showed that morel cultivation markedly altered soil nutrient structure, especially available nutrients and phosphorus-related indicators. Microbial analysis showed that A7 had the highest bacterial richness among the three sequenced treatments and stronger colonization by M. sextelata. Its bacterial and fungal communities were also more closely associated with soil organic carbon. Overall, A6 was more suitable for yield-oriented production, whereas A7 showed the best comprehensive performance when yield, nutritional quality, and soil ecological characteristics were considered together.