Arbuscular mycorrhizal enhancement of phosphorus uptake and yields of maize under high planting density in the black soil region of China

Arbuscular mycorrhizal (AM) symbioses are an attractive means of improving the efficiency of soil phosphorus (P) that difficult to be used by plants and may provide a sustainable way of maintaining high yields while reducing P applications. However, quantifying the contribution of indigenous AM fungi on phosphorus uptake and yields of maize (Zea mays L.) under field conditions is not particularly clear. Mesh-barrier compartments were applied to monitor the distribution of hyphal P uptake throughout the experimental period under different planting densities and soil depths, over two consecutive years. AM symbioses enhanced plant P-acquisition efficiency, especially during the silking stage, and hyphae of AM fungi was assessed to contribution 19.4% at most to total available P content of soil. Moreover, the pattern of AM depletion of soil P generally matched shoot nutrient demand under the high planting density, which resulted in significantly increased yield in 2014. Although the hyphal length density was significantly decreased with soil depth, AM fungi still had high potential for P supply in deeper soil. It demonstrates the great potential of indigenous AM fungi to maize productivity in the high-yield area of China, and it would further provide the possibility of elimination P fertilizer applications to maintain high yields.

Automated summary

The study found that arbuscular mycorrhizal symbiosis can enhance plant phosphorus acquisition efficiency, especially during the silking stage. Arbuscular mycorrhizal fungi may contribute up to 19.4% of the total available phosphorus content of the soil. Under high planting density conditions, the depletion of soil phosphorus by arbuscular mycorrhizal fungi matched plant nutrient demand, resulting in significantly increased yields in 2014.