The following trial, established in Germany by the DLR research centre on spinach crops, assessed the performance of Folur® and other foliar nitrogen fertilizers as a supplement to classic nitrogen fertilization via the soil. This study assessed the yield, photosynthesis activity and of nitrate content in the leaves. Furthermore, a comparison between both types of fertilization (foliar and soil) was carried out.

The results of this study show an increase in the yield and photosynthesis activity of Folur with regard to the two soil treatments (90 and 120 kg N/ha respectively) with regard to the two foliar fertilizers used in this test (urea 46 and ammonium nitrate).

Therefore, the use of Folur allows the total nitrogen dosage to be reduced. Figure 1 shows the differences in the increase of yield of Folur with regard to the other four treatments.


Trial conditions
• Research centre: DLR Neustadt – Germany.
• Date: 2002 and 2003.
• Crop: Spinach.
• Fertilization programme: Soil application of 90 kg N/ha to the soil for all the treatments (treatment 1, Folur, urea 46 and ammonium nitrate) except in a plot that was treated with 120 kg N/ha.
• Parameters assessed: Yield. Photosynthesis activity. Nitrate values in the leaves.

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