Agriculture Reference
In-Depth Information
a
60
effect of water
40
20
sandy soil
300
600
900
1200
1500
1800
2100
2400
wavelength in nanometers
b
effect of carbon
50
40
loamy soil
30
soil organic matter 1.72 x org. carbon
1600
2000
1200
2400
wavelength in nanometers
c
effect of soil type
30
water tension
= 0.1 bar
20
10
400
800
1200
1600
2000
wavelength in nanometers
Fig. 5.23
Soil Reflectance as affected by water, carbon and texture (
top
: from Zhu et al.
2010
;
center
: from Huang et al.
2007
;
bottom
: from Baumgardner et al.
1986
, all altered)
into account that these properties together with the clay content add up to 100 %.
Therefore, autocorrelation with the clay content must exist. And finally, soil water
content was not included in these investigations.
It is generally known that soil water can be sensed as precisely or even more
accurately than soil organic matter by near-infrared radiation (Mouazen et al.
2007
;
Viscarra Rossel et al.
2006
; Zhu et al.
2010
; Slaughter et al.
2001
). Actually, for
water, the sensing process is no problem. The question is whether the sensing for
