Excessive Nitrogen Fertilizer Application Causes Rapid Degradation of Greenhouse Soil in China

摘要

Greenhouse cultivation has expanded for years to provide vegetables for a growing population in China. It's reported that total area of greenhouse soil has reached 4.708 million hectares in 2019. To maintain good productivity, a large quantity of fertilizers was continuously applied to the soil. Due to low nitrogen (N) use efficiency, excessive nutrients are accumulated in soil profile. As a result, greenhouse soil is often compromised by the secondary soil salinization. This paper summarized the typical characteristics of secondary salinization of greenhouse soil such as nitrate accumulation and soil acidification as a result of excessive N application. The adverse impacts of soil salinization were also reviewed on major physical, chemical and biological properties of soil. It can be found that many physiological diseases due to nutrient disorder and soil borne diseases because of changes in soil microflora, are associated with higher salt concentration in soil and the lower soil pH. To reclaim the degraded soil with high nitrate concentration, an economical and environmentally friendly approach by incorporation of appropriate amount of plant materials with high C/N ratio into the soil was discussed. It was demonstrated that biomass addition could promote humification of nitrate with the help of microorganisms.