Effects of Rotary Tillage and Fertilization on Chemical Properties and Microbial Communities of Soil Under Continuous Morchella Mushroom Cultivation

The severe continuous cropping obstacles in Morchella cultivation, driven primarily by soil microecological imbalance, critically constrain the sustainable development of the industry. To address this challenge, this study evaluated the efficacy of rotary tillage, calcium cyanamide (CaCN2), and organic fertilizer, applied individually and in combination, in mitigating these obstacles and explored the underlying microbial mechanisms. The soil was treated on 5 August 2024, and soil samples were collected on 5 October 2024. Four treatments were established: continuous cropping control (CK), rotary tillage (XGX), rotary tillage combined with calcium cyanamide (MPD), and rotary tillage combined with calcium cyanamide and organic fertilizer (MPX). Soil chemical properties were analyzed in conjunction with metagenomic sequencing to characterize the responses of soil properties and microbial communities, including both eukaryotic and bacterial taxa. The results indicated that the MPD treatment showed a relatively pronounced effect in enhancing key soil fertility indicators, including soil organic matter (OM), total nitrogen (TN), available nitrogen (AN), available potassium (AK), and total phosphorus (TP). All amendments significantly altered microbial community structures. Specifically, the integrated MPX treatment effectively reduced the relative abundance of the pathogenic fungus Olpidium while maintaining higher overall microbial diversity. It also significantly promoted the abundance of Morchella itself and beneficial bacterial phyla such as Actinomycetota and Pseudomonadota. Redundancy analysis identified AN and AK as the primary drivers of eukaryotic community variation, whereas Availa-ble phosphorus (AP) and potential of hydrogen (pH) were the key factors shaping the bacterial community. The results indicated that MPD was the showed relatively pronounced effectiveness in rapidly improving soil fertility and suppressing pathogenic fungi. In contrast, MPX showed relatively better performance in optimizing microbial community structure, enhancing microbial diversity, and strengthening overall ecological stability. These two treatments exhibited distinct advantages in soil chemical improvement and microbial community regulation, respectively, thereby providing alternative practical strategies and a theoretical basis for the ecological management of continuous-cropping obstacles in Morchella cultivation. It should be noted that this study did not include treatments with calcium cyanamide alone, organic fertilizer alone, or their combined application without rotary tillage. This is primarily because rotary tillage is a standard land preparation practice in Morchella cultivation, and the use of soil amendments without accompanying tillage is rarely adopted under practical production conditions.