Effects of different organic fertilization regimes on soil physicochemical properties and bacterial community assembly to promote greenhouse-cultivated Aloe vera L. growth.

Sustainable production of greenhouse-cultivated Aloe vera L. largely depends on soil quality and rhizosphere microbial stability. Organic fertilization is widely applied to improve farmland soil environment, whereas the long-term effects of different organic fertilizer regimes on soil fertility, plant growth and rhizosphere bacterial community assembly remain unclear in intensive Aloe vera L. cultivation systems. This 4.5 years greenhouse trial was conducted to systematically investigate the regulatory effects of different organic fertilization practices on soil physicochemical properties, Aloe vera L. growth performance, and rhizosphere bacterial diversity and structure. Four treatments were set up in the experiment, including earthworm manure (QY), aloe-specific organic fertilizer (LY), conventional organic fertilizer (PY), and non-fertilized control (CK). Plant growth traits, soil fertility parameters, and rhizosphere bacterial community composition and diversity were comprehensively determined and compared across treatments. The results showed that long-term application of fertilization treatment significantly improved soil nutrient status, with the soil organic matter (SOM) content increased by 40.76% in QY treatment. Fertilization regimes altered diversity and structure of bacterial communities, while no significant difference in community composition was detected across treatments. The QY and LY treatments increased microbial community heterogeneity, while the PY and CK treatments maintained a relatively stable microbial community structure. SOM and available phosphorus (AP) were identified as the primary edaphic drivers governing phylum-level bacterial community variation. Notably, although the QY treatment showed positive effects on soil quality and metabolites production in Aloe vera L., it reduced leaf width and crown width. These results indicate that QY treatment unsuitable for Aloe vera L. cultivation targeting high yield, whereas it is still applicable for Aloe vera L. production by virtue of its performance in improving soil quality and maintaining microbial ecological stability, which can support the healthy and sustainable cultivation of Aloe vera L.