Agriculture Reference
In-Depth Information
For soil compaction detection, Glancey et al. (1989) tested a chisel device that
could estimate soil cutting force distribution. Adamchuk et al. (2001) designed and
tested a vertical blade for measuring soil mechanical impedance and resistance pres-
sure. They reported highly correlated estimated values. Chung et al. (2003, 2004)
developed an on-the-go soil strength profile sensor and reported
R
2
values of 0.61
and 0.52 to estimate prismatic soil strength index for a claypan soil field and a flood-
plain soil field, respectively. Mouazen and Ramon (2006) investigated an online
system for measuring soil draft, cutting depth, and moisture content. Adamchuk
and Christenson (2007) used strain gauges to develop an instrumented blade to map
soil mechanical resistance. Andrade-Sanchez et al. (2007) reported that the soil cut-
ting force was influenced by soil bulk density, moisture content, and the location of
the cutting element within the soil profile. Andrade-Sanchez and Upadhyaya (2007)
reported the development of the University of California-Davis soil compaction pro-
file sensor, and Andrade-Sanchez et al. (2007) reported that the device was able
to produce a soil cutting resistance variability map. Chung et al. (2006) developed
a soil strength profile sensor using load cells. Then, Sudduth et al. (2008) tested the
two previously developed on-the-go soil compaction sensors (soil compaction profile
sensor and soil strength profile sensor) and reported that the two sensors performed
similarly. Hemmat and Adamchuk (2008) suggested that the fusion of different sen-
sors could map spatially variable soil physical properties better.
4.2.2.2 RamanSpectroscopy
Raman spectroscopy was also used to predict some soil properties. A portable
Raman sensor was developed for measuring soil P content using a 785-nm laser
probe assembly and a detector array in 340-3460 cm
-1
(Bogrekci and Lee, 2005b).
Its lowest root mean square error was reported to be 151 mg/kg by PLS regression.
4.2.2.3 Electrodes
Another type of sensor to measure soil properties is an electrode. Since Adsett and
Zoerb (1991) explored ion-selective electrode (ISE) technology to measure soil nitrate
content, many researchers have tested this method. Adamchuk et al. (1999) devel-
oped an on-the-go soil pH sensing system and achieved good performance. Birrell
and Hummel (2001) tested a multiple ion-selective field effect transistors (ISFETs)
and reported that the ISFETs worked well for manually extracted soil nitrate content
in solutions, but not with samples from an automated soil solution extraction system.
Kim et al. (2006) investigated nitrate and potassium ion-selective membranes and
reported that the membranes showed linear response with higher nitrate and potas-
sium concentrations than 10
−4
mol/L. Kim et al. (2007a) found that cobalt rod-based
electrodes showed sensitive response over a typical phosphorus concentration range
in agricultural fields. Kim et al. (2007b) studied the applications of ISE to simul-
taneous measurement of soil primary nutrients (N, P, and K) and reported that the
NO
3
ISEs worked well; however, K and P ISEs showed lower detection accuracies.
Sethuramasamyraja et al. (2007) investigated the ISEs to detect soil pH, residual
nitrate (NO
3
-
), and soluble potassium (K
+
) contents, and reported that the soil type
and the soil/water ratio affected sensor performance. Adamchuk et al. (2007) sug-
gested field-specific calibration for more accurate pH mapping. Sethuramasamyraja
