Quick Determination of Soil Quality Using Portable Spectroscopy and Efficient Multivariate Techniques

Figure 6

Optimal wavelength range selection of Si-PLS prediction for soil properties: (a) nitrogen, (b) phosphorus, (c) potassium, (d) pH, (e) calcium, and (f) magnesium.

(a)

(b)

(c)

(d)

(e)

(f)