Transcript APA-mol ACP-mol 3590568. Y F 3590485. C P 3590401. 456427 3590318. 456427. A 4.08 3.92 3.76 3.59 3.43 3.27 3.11 2.95 2.78 2.622.46 X Spatial distribution of enzyme activities and related soil properties •Correlations between enzyme activity and clay content suggest that other PD-mol constituents held by clays may.

APA-mol
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ACP-mol
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F
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C
P
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456427
3590318.
456427.
A
4.08
3.92
3.76
3.59
3.43
3.27
3.11
2.95
2.78
2.62
456553
2.46
456679
456805
X
Spatial distribution of enzyme activities and related soil properties
•Correlations
between enzyme activity and clay content suggest that other
PD-mol
constituents held
by clays may influence activity (Tables 2 & 4).
2.33
3548388
5.76
5.39
5.02
4.65
4.29
3.92
3.55
3.18
2.81
2.44
2.07
1.70
1.34
0.97
0.60
0.23
A
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621805
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L
2.13
1.93
1.73
1.53
1.34
1.14
0.94
0.74
0.54
0.34
3548308
X
•Areas with the most exposure to animal manure (Site 1-pastured grazing
area and Site 2-litter storage area) showed the highest levels of activity for
both sites (Figures 3 & 7).
B
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456553.
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ACP-mol
3590651
Figure 2. Distribution of pH values amongst
sampled strata.
4.48
4.32
4.15
3.99
3.83
3.67
3.50
3.34
3.18
3.02
2.85
2.69
2.53
2.37
2.20
2.04
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B
Y
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2.14
2.08
2.02
1.96
1.90
1.84
1.78
1.72
1.65
1.59
1.53
1.47
1.41
1.35
1.29
1.23
B
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Figure 5. A map of the study area and
sampling design.
ACP-mol
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Figure 1. A map of the study area and
sampling design.
INTRODUCTION
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Figure 6. Distribution of pH values amongst
sampled strata.
Means differ significantly at the 0.05 level.
PD-mol
Figure 3. Distribution of enzyme activity across
sampled strata.
3590568
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2.74
2.60
2.47
2.33
2.19
2.05
1.92
1.78
1.64
1.50
1.37
1.23
1.09
0.95
0.82
0.68
2.33
2.20
2.06
1.93
1.80
1.67
1.53
1.40
1.27
1.14
1.00
0.87
0.74
0.61
0.47
0.34
C
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Study site 1 was located on the Sundown Ranch demonstration farm located at 32˚ 26’
latitude and -87˚ 27’ longitude on 17hectares of land in Perry County, Alabama, USA.
(Okolona silty clay loam [Fine, smectitic, thermic Oxyaquic Hapluderts; Kipling clay
loam [Fine, smectitic, thermic Vertic Paleudalfs])
Study site 2 was located at 32˚ 4’ latitude and -85˚ 42’ longitude on 4 hectares in
Bullock County, Alabama, USA. (Alaga loamy sand [Thermic, coated Typic
Quartzipsamments])
In accordance with the distinct land use types being exhibited across each site, the
sampling methodology of choice was a stratified random sampling design (Figures 1
& 5). Soil samples were collected from a 0-15cm depth. (n=45)
Phosphomonoesterases (Acid and Alkaline) were determined using the method of
Tabatabai and Bremner (1969) and phosphodiesterase was determined using the
Browman and Tabatabai (1978) method
Samples were analyzed for pH (1:2, soil/water), and 40-g subsamples were utilized for
particle size analysis.
Data was analyzed for significant statistical correlations (Pearson’s), and differences
in means using Statistical Package for Social Science (version 17.0; SPSS Inc., Chicago,
IL, USA). All geostatistical analyses were performed using GS+ software package
(Gamma Design, Plainwell, MI, USA).
•Exceptions to this pattern were APA in the forest floor and PD in the broiler
house floor, which can be tied to source-dependency of enzyme activity
(Parham et al, 2002). (Figures 3, 4, 7, & 8)
•Site 2, with a higher pH than Site 1, showed considerably less ACP activity,
and more APA activity.
Figure 7. Distribution of enzyme activity across
sampled strata.
Spatial autocorrelation of enzyme activities (Tables 1 & 3)
•The modeled semivariogram ranges of the enzymes are lower than like
studies modeling enzymes in undisturbed pasture soils (Askin and
Kizilkaya, 2006).
•The cause for such small ranges in the data may be attributed to abrupt
changes in microsites due to farm-level management decisions: animal
grazing preference, pine litter fall, shading, etc. (Bruckner et al., 1999). This
effect can also be seen in the patchiness of the modeled soil surfaces
(Figures 4 & 8).
•ACP is the exception as there is a large nugget effect, which perhaps is to
due to neutral and alkaline pH levels observed across the site.
MATERIALS AND METHODS
Differences between means are significant at the
0.05 level.
-PNP, p-nitrophenol.
Differences between means are significant at the
0.05 level.
-PNP, p-nitrophenol.
Table 1. Isotropic models fitted to variograms for APA, ACP, and PD.
•Areas with excessive litter layers (Site 1, strata F and Site 2, strata B), with
the capacity for inhibitory action (e.g. polyphenols from pine litter, heavy
metals from poultry litter) showed the least amount of activity (Kraus et al,
2003; Kpomblekou et al, 2002; Juma and Tabatabai, 1977).
•pH reflects this same pattern emphasizing the pH dependence of enzyme
activity (Comparing Figures 2 & 3; 6 & 7).
Means differ significantly at the 0.05 level.
Y
It has been previously understood by those engaged in soil research that measures of
soil biochemical and biological properties are ecosystem properties that occur within
microsites, but have continuous and extended functionality throughout an ecosystem
at the landscape level (Halvosrson et al, 1997; Parkin, 1993). Studies have begun to
assess the distribution of soil nutrients, biogeographical patterns of plant and animal,
but microbiological and biochemical activity of the soil has yet to be fully elucidated
geographically. There have been several studies which have begun the assessment of
enzyme activity at the field scale, landscape scale, and larger. The environments that
these studies were conducted in were pasture soils, urbanized areas, and freshwater
marsh soil and detritus (Askin and Kizilkaya, 2006; 2007; Prenger and Reddy, 2004).
Given the contributions of the aforementioned studies to the understanding of
hydrolytic enzymes and their spatial distribution, this study had the primary
objectives: (1) to determine if there is spatial dependency in phosphatase and
phosphodiesterase enzyme activity across the landscape, (2) to predict the soil surface
given the respective enzyme activities, and (3) to assess whether the variation of
enzyme activities across the landscape coincides with land use fragmentation.
5.26
4.95
4.64
4.34
4.03
3.72
3.41
3.10
2.80
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2.18
1.87
1.56
1.26
0.95
0.64
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Enzyme activity has been previously used as an indicator of environmental quality,
nutrient pool status, and the biochemical potential of soil ecosystems. The goal of this
study was to assess the activity of selected hydrolytic enzymes of the phosphorous
cycle (alkaline phosphatase [APA], acid phosphatase [ACP], and phosphodiesterase
[PD]) across two agricultural landscapes in relation to other physiochemical
parameters using geostatistical and spatial analyses. At site 1 we found there to be
lower values measured in the forested area, while at the second site, the lowest
activity was measured under poultry production houses. Ordinary Kriging models
were fit to semivariograms based upon the descriptive data measured. Model
performances were assessed by calculated r-square and residual sum of squares, and
soil surfaces generated by the predictive abilities of the models. Information on
patterns of spatial structure allowed for the interpretation of results in relation to the
landscape structure/use that could not be provided by conventional statistical
analysis.
APA-mol
3548388
Y
Site 1
RESULTS AND DISCUSSION
Site 2
Figure 8. Block-kriged map for A, alkaline phosphatase activity (APA); B, acid
phosphatase activity (ACP); C, phosphodiesterase activity (PD).
Y
ABSTRACT
Figure 4. Block-kriged map for A, alkaline phosphatase activity (APA); B, acid
phosphatase activity (ACP); C, phosphodiesterase activity (PD).
•The soil enzymes measured in the current study showed strong to
moderate spatial dependence, while modeling the empirical data relatively
well.
Table 3. Isotropic models fitted to variograms for APA, ACP, and PD.
CONCLUSIONS
Kriging Results for Selected Enzyme Activities
Kriging Results for Selected Enzyme Activities
Enzyme
Activities
Nugget (Co)
Sill (Co+C)
Range (Ao)
PSV
C/(Co+C)
Model
SD
r2
APA
0.17
2.88
24.00
0.94
G
S
0.94
•There exists a significant amount of clustering for each of the measured
Enzyme Activities
Nugget (Co)
Sill (Co+C)
Range (Ao)
PSV
C/(Co+C)
APA
0.35
1.94
39.40
0.82
S
S
0.75
ACP
0.15
1.33
26.90
0.88
S
S
0.86
ACP
1.22
1.37
216.50
0.11
L
W
0.67
•Information on patterns of spatial structure allowed for the interpretation
PD
0.16
0.51
88.00
0.69
E
M
0.76
PD
0.24
0.66
47.50
0.63
S
M
0.82
of results in relation to the landscape structure that could not be provided
by conventional statistical analysis.
Model
SD
r2
SD, spatial dependence: M, moderate; S, strong. Model: S, spherical; E, exponential. PSV, proportion of structural
variance
SD, spatial dependence; W, weak; M, moderate; S, strong. Model- S, spherical; L, linear; G, Gaussian. PSV, proportion of
structural variance
Correlations
ACP-mol
PD-mol
APA-mol
1
.116
.290**
ACP-mol
.116
1
.311**
PD-mol
.290**
.311**
1
pH
.258*
-.016
.435**
%Sand
.308**
-.321**
-.223*
%Silt
-.377**
.115
-.081
-.136
.338**
.345**
%Clay
•Qualitatively and quantitatively, interpolated surfaces for enzymes seem to
Correlations
APA-mol
APA-mol
1
.174*
.257**
.035
-.106
.258*
-.087
APA-mol
ACP-mol
PD-mol
pH
%Sand
%Silt
%Clay
enzymes in particular areas of interest.
ACP-mol
.174*
1
.148
-.245**
.157
-.034
-.208*
PD-mol
.257**
.148
1
.170*
-.243*
.525**
-.058
coincide with land use.
References
Askin, T. and Kizilkaya, R., 2006. Assessing spatial variability of soil enzyme activities in pasture topsoils using geostatistics. Eur. J. Soil Biol. Biochem. 42:230-237.
Askin, T. and Kizilkaya, R., 2007. The spatial variability of soil dehydrogenase activity: a survey in urban soils. Agriculturae Conspectus Scientificus, 72: 89-94.
Bandick, A.K., and Dick, R.P., 1999. Field management effects on soil enzyme activities, Soil Biol. Biochem. 31:1471–1479.
Browman, M.G. and Tabatabai, M.A., 1978. Phosphodiesterase activity in soils. Soil Sci. Soc. Am. J. 42:284-290.
Bruckner, A., E. Kandeler, and C. Kampichler , 1999. Plot–scale spatial patterns of soil water content, pH, substrate-induced respiration and N mineralization in a
temperate coniferous forest. Geoderma 93: 207–223.
**. Correlation is significant at the 0.01 level (2-tailed).
**. Correlation is significant at the 0.01 level (2-tailed).
GS+, Geostatistics for the Environmental Sciences, Gamma Design Software, Plainwell, MI, USA, 2008.
*. Correlation is significant at the 0.05 level (2-tailed).
*. Correlation is significant at the 0.05 level (2-tailed).
Juma, N.G., Tabatabai, M.A., 1977. Effects of trace elements on phosphatase activity in soils. Soil Science Society of America Journal 41, 343–346.
Table 2. Correlations (Pearson r value) between some soil properties and enzyme
activities.
Table 4. Correlations (Pearson r value) between some soil properties and enzyme
activities.
Acknowledgements: Collaborating Farmers- Mr. Jacob Waddy & Ms. Gwen Lewis-Gray
Kpomblekou-A, K. , R.O. Ankumah, and H.A. Ajwa. 2002. Trace and nontrace element contents of broiler litter. Communications in Soil Science and Plant Analysis,
v. 33 p. 1799-1811.
Kraus, T.E.C., Dahlgren, R.A., and Zasoski, R.J. 2003. Tannins in nutrient dynamics of forest ecosystems — a review. Plant Soil, 256: 41–66.
Parkin, T.B., 1993. Spatial variability of microbial processes in soil: a review, J. Environ. Qual. 22:409–417.
Prenger, J.P., and Reddy, K.R., 2004. Microbial enzyme activities in a freshwater marsh after cessation of nutrient loading. Soil Sci. Soc. Of Am. J. 68:1796–1804.
Funding through: NSF IGERT-CREATE
Tabatabai, M.A., and Bremner, J.M., 1969. Use of p-nitrophenyl phosphate for assay of soil phosphatase activity, Soil Biol. Biochem. 1:301–307.