The soil-plant interaction team of the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) revealed that the soil nitrogen gradient has a significant impact on the occurrence of early blight and the abundance of 39 potential crop fungal pathogens, highlighting the important role of rational nutrient management in the regulation of soil and crop health. The results were published in Applied Soil Ecology.

According to Prof. Fan Fenliang, nitrogen is an essential nutrient element for plant growth and development, and it also affects the occurrence of plant diseases. However, there is currently a lack of systematic research on how nitrogen fertilizer affects the risk of multiple diseases in crops.

The research team used tomato as a model crop, set seven nitrogen fertilizer application gradients (0-800 mg/kg), and carried out experiments in greenhouses with a history of various crop diseases. The results showed that the incidence and disease index of tomato early blight increased with the increase of nitrogen application rate, and the incidence and disease index were positively correlated with plant nitrogen content and negatively correlated with fungal community diversity.

In addition to the early blight pathogen Alternaria alternata, 39 other types of fungal pathogens were identified in tomato leaves, roots and soil, and the distribution and dynamic succession of these pathogens varied with nitrogen levels.

The study shows that nitrogen fertilization can affect multiple crop disease risk by systematically altering pathogen abundance, crop physiology and plant microbiomes, highlighting the need for proper nutrient management as an integral part of sustainable integrated pest management in agriculture .

The research was funded by the National Key Research and Development Program of China, and the Fundamental Research Funds for Central Non-profit Scientific Institution.

Paper link:  https://doi.org/10.1016/j.apsoil.2022.104445