PSI PlantPen/N-Pen N 110, Инструкция по эксплуатации

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4.3 N
ITROGEN NUTRITION
The outcome of the measurement with N-pen is formulated as relative N-content in plant dry matter (%). Another practical interpretation
of the NDGI value, is the N nutrition state (Fig. 5). The maximum NDGI value is set to 100 % and the minimum reflectance is set equal to
0 % as follows:
1. NDGI > 0.65 indicates 100% N nutrition state (N = 100 %)
2. NDGI < 0.25 indicates 0 % N (N = 0 %)
3. If 0.65 > NDGI > 0.25, then nutrition state is calculated as N (%) = (NDGI - 0.25) * 250
As a general rule, nutrition state at early stages of development characterized by onset of tillering should be maintained at higher levels.
Later, during shoot elongation and emerging flag leaf, (Novoa and Loomis 1981).
Fig. 4 N-Pen configuration.
Fig. 5 Prediction of relative N nutrition from NDGI.