Variations in soil fungal communities after continuous fertiliser treatment under the ridge and furrow rainfall harvesting system in a semiarid region of China

The ridge and furrow rainfall harvesting (RFRH) system enhances the rainfall use efficiency and crop yield in rain-fed areas of north-western China. In this study, we determined the effects of RFRH on the soil fungal community composition and diversity in a 5-year fertilisation experiment (N : P fertiliser rates of 0 : 0, 150 : 75, 300 : 150, and 450 : 225 kg ha–1 year–1) in the dryland farming area of the Loess Plateau. Excessive fertiliser application reduced the crop productivity and a moderate rate of 300 : 150 kg ha–1 year–1) produced the highest maize yield. The available phosphorus (AP), organic carbon, nitrate-nitrogen (NO3-N) and total nitrogen contents increased with the fertiliser rate, whereas soil water content decreased. The relative abundances of Ascomycota, Fusarium and Zygomycota increased (P < 0.05) with the fertiliser application rate, whereas those of Basidiomycota and Glomeromycota decreased (P < 0.05). The fungal diversity (Shannon–Wiener index: P = 0.016) and composition (unweighted UniFrac: P = 0.024) were significantly affected by fertilisation. The NO3-N and AP were the main factors that affected fungal composition and diversity. Thus, fertilisation changed the fungal community composition and diversity, and a higher fertiliser rate negatively affected nutrient cycling and the stability of the soil ecosystem under RFRH.