engleski

Leached Phosphorus Measured in Drainage Water Through a Field Experiment With Varying Nitrogen Rates

The effect of mineral fertilisation on the concentration of phosphate in subsurface drainage water was studied in a field experiment in Central Croatia with different nitrogen rates (from 0 up to 300 kg/ha) and constant P (120 kg/ha) and K (180 kg/ha) rates. Increased rates of applied nitrogen led to lower average values of P-PO4 concentration in drainage water. Average P-PO4 concentration observed in the investigation period (1997 - 2010) was in a range from 0.09 mg/l P-PO4 in the treatment with 250 kg N/ha up to 0.21 mg/l P-PO4 in the treatment with no nitrogen applied, but with P and K application. Average losses of P-PO4 through drainage water, over a 14-year-long investigation period varied from 0.08 to 0.22 kg/ha, depending on the nitrogen rates applied. The concentration of P-PO4 in drainage water and P-PO4 losses were in a complete negative correlation (r=0.9151 ; r=0.9292, respectively) with N fertilisation doses applied.

drainage; phosphate; leaching; fertilisation; P loss

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