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Effects of urea, ammonium, and nitrate nitrogen on the yield and quality of greenhouse lettuce grown on different media

Iwona Kowalska

Department of Soil Cultivation and Fertilization
Faculty of Horticulture, Agricultural University
29 Listopada 54, 31-425 Kraków, Poland

The effect of reduced forms of N (N-NH2 and N-NH4), compared with N-NO3, on the yield and quality of greenhouse lettuce grown on peat and soil were investigated. Fresh and dry matter yields were significantly affected only by the growing media. The average fresh-head weight of plants grown on peat was considerably higher than that of plants grown on soil. Fertilization with reduced nitrogen forms increased N-NH4 content in the plants. On the other hand, the nitrate form enhanced N-NO3 accumulation. Although the effect of the nitrogen form on the content of other mineral nutrients (P, K, Ca, Mg) was significant, differences between treatments seeming not to be of importance. Reduced N forms significantly improved the quality of the lettuce by reducing the nitrate content. The effect was particularly evident in plants grown on peat.

Kowalska I., 1997. Effects of urea, ammonium, and nitrate nitrogen on the yield and quality of greenhouse lettuce grown on different media. Folia Horticulturae 9/2: 31-40.