Nitrogen and phosphorus fertilization leads to soil arbuscular mycorrhizal fungal diversity changes and rainfed crop yield increase on the Loess Plateau of China: A 37-year study

More than 80% of plants mutualistic symbiosis with arbuscular mycorrhizal fungi (AMF). Fertilization, such as nitrogen (N) and/or phosphorus (P) addition, is a common agricultural management practice to improve crop yield and quality. However, the potential effects of long-term N and/or P fertilization on the AMF community in the rainfed agricultural system of the Loess Plateau are still not well understood. Based on the Changwu Agricultural Ecology Experimental Station, a 3×3 complete interaction experiment with three gradients of N (0 kg ha−1 y−1, 90 kg ha−1 y−1, 180 kg ha−1 y−1) and P (0 kg ha−1 y−1, 90 kg ha−1 y−1, 180 kg ha−1 y−1) fertilization rate in a long-term wheat field was carried out. Combining traditional biochemical methods with high-throughput sequencing technology, the change in the AMF community and the correlation between AMF community composition, soil environmental factors and crop yield component traits were analyzed. The results showed that long-term N and/or P addition had a significant effect on the AMF community structure and composition. The single N application significantly reduced the richness and diversity of AMF community, while the combined N and P application significantly increased them. The AMF community was driven mostly by soil available phosphorus (AP), total phosphorus (TP) and pH. There was a significant positive correlation between Glomus and wheat yield, while Paraglomus had the opposite correlation. Long-term N and/or P addition not only directly increased crop yield but also affected yield indirectly by affecting soil chemical properties and the AMF community. Appropriate N (90 kg ha−1 y−1) and P application (90 kg ha−1 y−1) could improve the ecological and physiological functions of the AMF community and benefit the sustainable development of rainfed agriculture.