Study on fertilization techniques for greenhouse vegetable in Shanghai suburbs

Shanghai has been experiencing a rapid expansion of lands planted to vegetables, which as of 2009 cover over 6,670 ha. However, this growth in highly intensive cropping is also raising issues related to soil fertility degradation such as secondary soil salinization and soil acidification. The Environmental Resource Institute, Shanghai Academy of Agricultural Science, established this project in 2010 to study better nutrient management strategies for greenhouse vegetable production within the Shanghai suburbs.

In 2010, basic information on local nutrient management was collected along with soil samples for fertility analysis. According to this investigation, the main issues include the significant accumulation of nitrate (NO₃-N) and available P in greenhouse vegetable soils. The average soil nitrate content has reached 382 mg/kg, while the average content of available soil P was also rather high at 154 mg/kg. Available soil K was low in a portion of lands under greenhouse production. Secondary soil salinization is currently a serious issue with about 91% of surface soil under greenhouse vegetable production having salt contents between 0.3% to 2.4%. Shanghai-09