Effect of Nitrogen Nutrition Diagnosis on Cucumber in Greenhouse

Using the SPAD-502 chlorophyll meter and nitrate reflectometer to study diagnosis of nitrogen nutrition on the cucumber(Cucumis sativus) in greenhouse.The results showed that fertilization had effect on leaves SPAD values and with a certain amount of nitrogen increases the SPAD values are also increased.The new leaves and mature leaves of the SPAD's the ratio reflects of nitrogen nutritional status.The mature leaves of SPAD values correlation with nitrogen is greater than the new leaves'.Fertilization also affected the nitrate content of petiole.In a certain amount,the nitrate content of petiole increased with the nitrogen.In the fruiting stage,there is a linearly correlate between nitrate content and nitrogen consumption(r=0.960 6).Each additional 1kg of nitrogen fertilizer,nitrate concentrations increase 10-30 mg/kg,late top-dressing is more easy cause the accumulation of nitrate.