Response of soil arbuscular mycorrhizal fungal community to chemical fertilization in sugarcane

Most sugarcane cultivation areas in China have undergone over 30 years of continuous monocropping, and long-term chemical fertilizer application has led to severe soil degradation. Arbuscular mycorrhizal fungi (AMF) play a crucial role in promoting plant nutrient uptake, enhancing plant stress tolerance, and improving soil quality and restoration. However, in agroecosystems, AMF are susceptible to the effects of cultivation, fertilization, and other factors. The goal of this study was to investigate the influence of chemical fertilization on the AMF community in the rhizosphere soil of plant crop of sugarcane. In this study, sugarcane varieties GT58 and GT29 were selected for experiment. Four different chemical fertilization rates were established using controlled-release compound chemical fertilizer (N: P: K = 17:7:17): T1 (0.0 kg/ha), T2 (562.5 kg/ha), T3 (1,125.0 kg/ha), and T4 (2,250.0 kg/ha). The results showed that different fertilization rates significantly affected the cane yield in GT58. T3 and T4 increased the cane yield by 12.67% and 11.11%, respectively, compared to the control T1 ( P < 0.05). The impact on the cane yield in GT29 was not significant. The diversity indices of root-associated AMF in GT58 (Chao index and Shannon index) varied significantly in different fertilization rates. T3 had the highest diversity, showing no significant difference from T1 and T2 but significantly higher than T4. For GT29, there were no significant differences in the diversity indices of root-associated AMF among different fertilization rates. Analyzing the differential species in root-associated soil with different fertilization rates in GT58 at the OTU level revealed that T3 had significantly higher abundances for 5 OTUs compared to the other treatments, and all the differentially abundant species belonged to Glomus . The Mantel analysis revealed that the genus Acaulospora was significantly and positively correlated with millable stalks ( P < 0.001), and significantly and positively correlated with tiller number ( P < 0.05). The genus Scutellospora showed a significant positive correlation with sprouting rate ( P < 0.05). However, the other AMF genera did not show significant correlations with the agronomic traits of sugarcane. In summary, different chemical fertilization rates significantly affected the cane yield in GT58 and the AMF community in the rhizosphere soil, but not in GT29, which suggests that sugarcane chemical fertilization should consider different sugarcane varieties and the diversity of AMF communities in soil.