RESUMEN
A long-term fertilizer experiment was conducted to determine the precise effects of nitrogen (N) fertilization on the yield and quality of cucumber, which were grown in greenhouse located in the coastal hilly region of East China. This work included four treatments with varying levels of chemical N application (N1, 800 kg·hm-2, N2, 600 kg·hm-2 and N3, 400 kg·hm-2, CK, no fertilization) plus ON (organic N 400 kg·hm-2). Results showed that a 50% reduction of N fertilization (N3) produced no significant effects on yield, when compared with the local conventional practice (N1). Importantly, fruit nitrate content for cucumbers with N fertilization ranged from 94.2 to 136.1 mg·kg-1, which was acceptable according to the National Food Safety Standard of China. However, when compared with no fertilization control, N fertilization increased nitrate content by 18.1%-44.5%. Chemical N fertilization resulted in a decrease of vitamin C, soluble sugar and soluble protein contents in cucumber, and caused significant temporary changes of soil pH and other chemical and physical properties of the soil. No significant correlations were found between cucumber yields, economic benefit and soil property variables under the excessive use of N fertilizer. It was concluded that N fertilization could be reduced by half with no significant reduction of fruit yield and quality for cucumbers cultivated in greenhouse located in the coastal hilly region of East China.