As an important component of terrestrial soil carbon reservoirs, the agricultural soil organic carbon pool is greatly influenced by cultivation patterns. Coffee, one of the major economic crops in tropical regions of the world, a minor changes of its cultivation pattern can significantly affect the carbon balance of terrestrial ecosystems. Mulching cultivation is one of the traditional cultivation models for coffee, but its impact on the organic carbon composition of coffee plantation soil is still unclear. Therefore, based on the previous research of our team using coffee peel and leaf litter as substitutes for traditional mulch to cultivate coffee, four mulching treatments were set up in this study: uncovered coffee waste (CK), coffee leaf litter mulch (L), coffee peel mulch (P), and both coffee peel and litter mulch (PL). Soil micro-environment, microbial community diversity and biomass, organic carbon fractions, and other indicators were monitored in the coffee plantation, and the intrinsic relationships between soil micro-environment, microbial community structure, and organic carbon fractions were analyzed to investigate the effects of coffee waste cover on soil components and the key driving factors. The results showed that coffee waste cover did not affect the content of soil organic carbon (SOC), heavy fraction organic carbon (HFOC), and dissolved organic carbon (DOC), while coffee peel and litter mulch significantly increased the content of soil light fraction organic carbon (LFOC) by 13.31% and 14.12%, respectively. Coffee waste mulch did not affect soil micro-environment indicators or microbial diversity. Coffee peel cover significantly increased soil microbial biomass by 14.05%, and increased the relative abundance of Proteobacteria and Firmicutes by 18.60% and 80.77%, respectively, while reducing the abundance of Cyanobacteria by 70.14%, but had little impact on soil fungal community. Coffee litter mulch significantly increased the relative abundance of Proteobacteria and Firmicutes by 14.43% and 57.63%, respectively, while reduced the abundance of Cyanobacteria by 73.43%, and significantly increased the relative abundance of dominant fungi Ascomycota by 14.79%. The reason why coffee waste mulch did not affect the soil organic carbon content is mainly attributable to the insensitivity response of HFOC content to coffee waste mulching. The increase of microbial biomass and the increase relative abundance of Firmicutes are the main reasons to enhance the excitation effect caused by external organic carbon input, thus significantly increasing the content of soil LFOC content. The short-term mulch of coffee waste significantly increased the content of soil LFOC content, which is contribute to improve the soil carbon storage of coffee plantations and optimize the green and low-carbon production mode of coffee.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |