The impact of P fertilization on root colonization by arbuscular mycorrhizal fungi (AMF) remains understudied in field conditions. High P availability related to excess P-fertilization is expected to reduce root colonization by AMF. We challenged this view in a field experiment for a range of AMF and maize genotypes. Maize was grown at no vs excess P levels in a long-term P-fertilizer trial comprising alkaline vs neutral soils. Root colonization was assessed by microscopic observation and qPCR targeting Funneliformis mosseae and Rhizophagus irregularis. The functionality of AMF colonization in roots was assessed by measuring the expression of 2 P-transporters by qPCR. Regardless of the soil type, root colonization by AMF was higher in the no-P treatment than at high-P fertilization. Looking closer, this drop was driven by the neutral soil and no such variation was observed in the alkaline soil. In spite of a similar, extremely low level of available P in both soils, the no-P treatment was particularly harsh for maize development in the neutral soil, triggering a higher expression of the plant P starvation inducible gene (ZmPT1:3), and lower plant growth and P content. Under these conditions, the mycorrhizal P uptake pathway was activated, as evidenced through increased expression of the AM inducible P transporter (ZmPT1;6). In contrast, its expression was unchanged by P fertilization in the alkaline soil. The limited impact of excess P fertilization in the alkaline soil could partially be due to the high abundance of F. mosseae, which even increased at high P. Our results emphasize the importance of considering soil properties which differentially impacted AMF and plant responses to P fertilization, and varied with AMF species and maize genotype.