Soil Acidification caused by excessive application of nitrogen fertilizer aggravates soil-borne diseases: Evidence from literature review and field trials

Modern high input–based intensive cropping systems often lead to the deterioration of the soil environment, which is one of the main driving factors for the build-up of soil-borne pathogens. However, soil chemical properties are complex and variable, and it is important to clarify the main factors driving soil-borne pathogens. In this study, meta-analysis and field experiment were used to determine the key soil chemical factors affecting soil-borne diseases. Our data demonstrated that a decrease in the soil pH was the key soil chemical factor that aggravated soil-borne diseases. Among the complex soil chemical factors, the increase in available nitrogen (AN) caused by excessive application of nitrogen fertilizer and the accumulation of phenolic acids were the main driving factors for the decrease in the soil pH value. Field experiments on Panax notoginseng , which is susceptible to nitrogen and suffers from serious soil-borne disease, showed that a high level of AN (≥350 mg kg −1 ) in soil caused by overuse of nitrogen fertilizer could decrease the pH and aggravate soil-borne disease. However, exogenous quicklime (600–1200 kg hm −2 ), calcium magnesium phosphate fertilizer (600–1200 kg hm −2 ), and organic fertilizer (1050–1500 kg hm −2 ) in acidic soil could effectively increase the soil pH value and alleviate soil-borne disease. Our results highlight that soil-borne disease can be aggravated by overuse of nitrogen fertilizer and can be alleviated by modifying soil to a suitable pH level. • Soil acidification is the key soil chemical factor to aggravate soil-borne diseases. • The increase in available nitrogen and phenolic acids could decrease the soil pH. • Soil-borne disease can be managed by modifying soil to a suitable pH level.