Fuente: Microorganisms - Revista científica (MDPI) Microorganisms, Vol. 13, Pages 2841: Ecological Modulation of Soil Microbial Communities by Fertilization Regimes: Insights from Castor Bean Cake, Chemical Fertilizers, and Organic Fertilizer
Microorganisms doi: 10.3390/microorganisms13122841
Authors:
Chongyang Hu
Yalijuan Wu
Zecheng Li
Zhiyong Wang
Fenglan Huang
Zhiquan Fan
Mu Peng

Fertilization plays a vital role in replenishing soil nutrients, shaping microbial community composition, and enhancing agricultural productivity. Castor bean cake (CBC) is a nitrogen- and carbon-rich by-product increasingly used as an organic amendment, yet its effects on soil microbiomes remain unclear. Here, we compared CBC with a compound chemical fertilizer (CF) and a manure-based organic fertilizer (OF) across dose gradients using 16S rRNA sequencing and multi-level ecology analyses (α/β diversity, co-occurrence networks, and community assembly models). The results revealed that CBC increased bacterial richness and phylogenetic breadth relative to the unfertilized cultivated control, whereas OF showed dose-dependent declines in richness and CF maintained relatively stable richness with slight reductions in evenness at higher doses. Phylum-level composition shifted strongly with fertilizer identity: Bacillota decreased, whereas Pseudomonadota and Acidobacteriota increased under fertilization, with the largest compositional changes under CBC. CBC strengthened nutrient–enzyme–microbe coupling and generated increasingly complex, highly connected, and robust co-occurrence networks along the dose gradient, outperforming high-dose OF in network complexity and robustness, while OF maintained higher modularity. Null-model partitions (βNTI/RC_bray, NST, NCM, iCAMP) indicated that stochastic processes dominated community assembly across treatments; along the CBC gradient, dispersal limitation decreased from CBC1 to CBC2 and drift remained dominant, indicating increasing stochastic stabilization at moderate–high doses. Together, CBC promoted microbiome recovery and ecological resilience and represents a promising amendment for soil health.