Nitrogen fertilization of Virginia tobacco. Role of the mineral nitrogen content of the soil
1990
Gondola, I.
In determining the optimum rate of fertilization, the mineral N content of the soil was taken into consideration besides the humus analysis. The method can be used to avoid quality deterioration due to over-fertilization with N. The spring nitrate-N content of the soil significantly influences yields and the response to N fertilizers. The net quantity of mineralized N can be estimated at the end of the vegetation period by adding the NO3-n extracted by the corp to the amount left in the soil after harvesting and subtracting the spring NO3-N content of the soil. The N fertilizer response of Virginia tobacos changes substantially as a function of the available mineral N content of the soil; this can be seen most clearly in the production value. On a sandy soil with a favourable water regime, the NO3 + NO2 - N reserves of the top 0-60 cm soil layer may unnecessitate the fertilization of the tobacco plant. Thus, advice on fertilization should be based on calculations taking into account the mineral N content of the soil.
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