Nitrate Accumulation in Vegetables, I. Spinach Grown in Upland Soils1
- A. V. Barker,
- N. H. Peck and
- G. E. MacDonald2
The nitrate concentrations in spinach (Spinacia oleracea L.) blades and petioles were determined for different sources and times of application of N fertilizers to a Honeoye fine sandy loam and a Lima silt loam to determine the effect of N fertilization on the concentration of nitrates in the plant parts used for consumption for food.
Nitrate concentrations were determined potentiometrically, using a nitrate-selective ion electrode, on plant samples taken at time intervals after N fertilization and at harvest stage for processing. Nitrogen fertilization substantially increased the NO3 concentrations of spinach grown in upland soils. The following observations were significant: (a) More NO3 accumulated in leaves of plants broadcast with N fertilizers before planting than if an equivalent amount of N fertilizer was supplied by sidedressing one week before harvest. (b) The N carrier was a significant factor in governing NO3 accumulation when it was applied as sidedressing.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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