This R Markdown document contains all statistical analysis and visualization to date of Dari’s agroforestry project, as completed by Murray Sternberg.

One-way ANOVAs were performed to analyze the effects of agroforestry type (pecan vs. pine), cover crop type (for pecan, pine, and the two sites combined), and tillage (no-till vs. minimum tillage) on biological parameters. Two-way ANOVAs were perforemd to analyze the effects and interactions of tillage and agroforestry type, and tillage and cover crop type on biological parameters. For one-way ANOVAs with significant results, post-hoc testing of multiple comparisons between groups was done using Tukey’s HSD test.

Biological parameters (response variables) included microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), 24-hour soil microbial respiration, enzyme activities, microbial necromass, total soil carbon (TC), and total soil nitrogen (TN). Statistical significance was calculated with a significance level of 0.05.

TC & TN data is not yet available but will be analyzed and incorporated when the instrument is available.

This document is broken into 5 main sections, each representing a parameter to be analysed (shown in the table of contents), followed by visualizations of summary statistics. Each section starts off with a summary of significant and non-significant results. Within each section, there are 6 main subsections, each representing a statistical comparison:

  1. pecan vs. pine (with control),
  2. the 10 cover crop types, combined (with control),
  3. the 6 cover crop types used for pecan (with control),
  4. the 4 cover crop types used for pine (with control),
  5. no-till vs. minimum tillage, and
  6. two-way ANOVAs (agroforestry type * tillage, cover crop type * tillage).

Microbial Biomass C

Significance Summary:

When considering all 3 seasons of data, the following analyses were found to be significant:

  • Agroforestry Tree Type

The following analyses were not significant:

  • Cover Crop Type - Combined Pecan & Pine
  • Cover Crop Type - Pecan
  • Cover Crop Type - Pine
  • Tillage Treatment
  • No interaction between tree type and tillage
  • No interaction between cover crop type and tillage

Agroforestry Type

# perform anova 
anova_MBCagrotype <- aov(MBIO_C ~ agro_type,  data = mbc_nocntrl)
summary(anova_MBCagrotype)
##             Df Sum Sq Mean Sq F value Pr(>F)  
## agro_type    1  58316   58316   5.676 0.0212 *
## Residuals   48 493170   10274                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 10 observations deleted due to missingness

The ANOVA revealed that there was a statistically significant difference in microbial biomass C between agroforestry tree type (pecan vs. pine) when considering all 3 seasons of data (p < 0.001).

Cover Crop Type (Combined)

# perform anova for combined for all seasons
anova_MBCCCtype <- aov(MBIO_C ~ cc_type,  data = mbio_all_avg)
summary(anova_MBCCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type     10 148966   14897   1.351  0.236
## Residuals   43 474185   11028               
## 10 observations deleted due to missingness

The ANOVA revealed that there was not a statistically significant difference in microbial biomass C between cover crop type when considering both sites combined (pecan and pine) with all 3 seasons of data.

Cover Crop Type (Pecan)

# perform anova for pecan for all seasons
anova_MBCpecCCtype <- aov(MBIO_C ~ cc_type,  data = mbcPEC)
summary(anova_MBCpecCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type      5  75900   15180   1.434   0.25
## Residuals   23 243549   10589               
## 7 observations deleted due to missingness

The ANOVA revealed that there was not a statistically significant difference in microbial biomass C between cover crop type (of the 6 types) for the pecan site when considering all 3 seasons of data.

Cover Crop Type (Pine)

# perform anova for pine for all seasons
anova_MBCpinCCtype <- aov(MBIO_C ~ cc_type,  data = mbcPIN)
summary(anova_MBCpinCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type      3  13010    4337   0.459  0.715
## Residuals   17 160711    9454               
## 3 observations deleted due to missingness

The ANOVA revealed that there was not a statistically significant difference in microbial biomass C between cover crop type (of the 4 types) for the pine site when considering all 3 seasons of data.

Tillage Treatment

# perform anova for all seasons
anova_mbcTIL <- aov(MBIO_C ~ tillage,  data = mbcTIL)
summary(anova_mbcTIL)
##             Df Sum Sq Mean Sq F value Pr(>F)  
## tillage      1  50458   50458   4.834 0.0328 *
## Residuals   48 501028   10438                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 10 observations deleted due to missingness

The ANOVA revealed that there was not a statistically significant difference in microbial biomass C between tillage treatments (minimum tillage vs. no-till) when considering all 3 seasons of data.

Two-Way ANOVAs

# Performing two-way ANOVA for MBIO-C using Agroforestry Type & Tillage
anova_MBC_agtl <- aov(MBIO_C ~ agro_type * tillage, data = mbc_nocntrl)
summary(anova_MBC_agtl)
##                   Df Sum Sq Mean Sq F value Pr(>F)  
## agro_type          1  58316   58316   6.141 0.0169 *
## tillage            1  49759   49759   5.240 0.0267 *
## agro_type:tillage  1   6616    6616   0.697 0.4082  
## Residuals         46 436796    9496                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 10 observations deleted due to missingness

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of agroforestry type and tillage.

# Performing two-way ANOVA for MBIO-C using Cover Crop Type & Tillage
anova_MBC_cctl <- aov(MBIO_C ~ cc_type * tillage, data = mbc_nocntrl)
summary(anova_MBC_cctl)
##                 Df Sum Sq Mean Sq F value Pr(>F)  
## cc_type          9 147226   16358   1.510 0.1895  
## tillage          1  39490   39490   3.646 0.0658 .
## cc_type:tillage  9  39862    4429   0.409 0.9203  
## Residuals       30 324908   10830                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 10 observations deleted due to missingness

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of cover crop type and tillage.

Microbial Biomass N

Significance Summary:

When considering all 3 seasons of data, the following analyses were found to be significant:

  • None

The following analyses were not significant:

  • Agroforestry Tree Type
  • Cover Crop Type - Combined Pecan & Pine
  • Cover Crop Type - Pecan
  • Cover Crop Type - Pine
  • Tillage Treatment
  • No interaction between tree type and tillage
  • No interaction between cover crop type and tillage

Agroforestry Type

# perform anova for all seasons
anova_MBNagrotype <- aov(MBIO_N ~ agro_type,  data = mbn_nocntrl)
summary(anova_MBNagrotype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## agro_type    1     37    36.7   0.039  0.844
## Residuals   43  40100   932.6

The ANOVA revealed that there was not a statistically significant difference in microbial biomass N between agroforestry tree type (pecan vs. pine) when considering all 3 seasons of data.

Cover Crop Type (Combined)

# perform anova for combined for all seasons
anova_MBNCCtype <- aov(MBIO_N ~ cc_type,  data = mbn)
summary(anova_MBNCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type     10   7608   760.8    0.87  0.568
## Residuals   38  33238   874.7

The ANOVA revealed that there was not a statistically significant difference in microbial biomass N between cover crop type when considering both sites combined (pecan and pine) considering all 3 seasons of data.

Cover Crop Type (Pecan)

# perform anova for pecan for all seasons
anova_MBNpecCCtype <- aov(MBIO_N ~ cc_type,  data = mbnPEC)
summary(anova_MBNpecCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type      5   4290     858   1.709  0.184
## Residuals   18   9036     502

The ANOVA revealed that there was not a statistically significant difference in microbial biomass N between cover crop type (of the 6 types) for the pecan site considering all 3 seasons of data.

Cover Crop Type (Pine)

# perform anova for pine for all seasons
anova_MBNpinCCtype <- aov(MBIO_N ~ cc_type,  data = mbnPIN)
summary(anova_MBNpinCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type      3   2857   952.2   0.677  0.578
## Residuals   17  23917  1406.9

The ANOVA revealed that there was not a statistically significant difference in microbial biomass N between cover crop type (of the 4 types) for the pine site considering all 3 seasons of data.

Tillage Treatment

# perform anova for all seasons
anova_mbnTIL <- aov(MBIO_N ~ tillage,  data = mbnTIL)
summary(anova_mbnTIL)
##             Df Sum Sq Mean Sq F value Pr(>F)
## tillage      1    555   555.4   0.603  0.442
## Residuals   43  39582   920.5

The ANOVA revealed that there was not a statistically significant difference in microbial biomass N between tillage treatments (minimum tillage vs. no-till) considering all 3 seasons of data.

Two-Way ANOVAs

# Performing two-way ANOVA for MBIO-N using Agroforestry Type & Tillage
anova_MBN_agtl <- aov(MBIO_N ~ agro_type * tillage, data = mbn_nocntrl)
summary(anova_MBN_agtl)
##                   Df Sum Sq Mean Sq F value Pr(>F)
## agro_type          1     37    36.7   0.040  0.842
## tillage            1    547   547.4   0.603  0.442
## agro_type:tillage  1   2306  2305.7   2.538  0.119
## Residuals         41  37247   908.5

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of agroforestry type and tillage.

# Performing two-way ANOVA for MBIO-N using Cover Crop Type & Tillage
anova_MBN_cctl <- aov(MBIO_N ~ cc_type * tillage, data = mbn_nocntrl)
summary(anova_MBN_cctl)
##                 Df Sum Sq Mean Sq F value Pr(>F)
## cc_type          9   7183   798.2   0.777  0.639
## tillage          1    646   646.4   0.629  0.435
## cc_type:tillage  8   5584   698.0   0.679  0.705
## Residuals       26  26723  1027.8

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of cover crop type and tillage.

24-Hour Microbial Respiration

Significance Summary:

When considering all 3 seasons of data, the following analyses were found to be significant:

  • Agroforestry Tree Type
  • Cover Crop Type - Combined Pecan & Pine
  • Cover Crop Type - Pecan

The following analyses were not significant:

  • Cover Crop Type - Pine
  • Tillage Treatment
  • No interaction between tree type and tillage
  • No interaction between cover crop type and tillage

Agroforestry Type

# perform anova 
anova_CMINagrotype <- aov(`mg CO2/g dry weight` ~ agro_type,  data = cmin_nocntrl)
summary(anova_CMINagrotype)
##              Df Sum Sq Mean Sq F value   Pr(>F)    
## agro_type     1   71.0   71.02   32.99 3.93e-08 ***
## Residuals   178  383.1    2.15                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in microbial respiration between agroforestry tree type (pecan vs. pine) (p < 0.001).

Cover Crop Type (Combined)

# perform anova 
anova_CMINCCtype <- aov(`mg CO2/g dry weight` ~ cc_type,  data = cmin_allcc)
summary(anova_CMINCCtype)
##              Df Sum Sq Mean Sq F value   Pr(>F)    
## cc_type       9  108.1  12.009   5.899 3.71e-07 ***
## Residuals   170  346.1   2.036                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in microbial respiration between cover crop type when considering both sites (pecan and pine) combined (p < 0.001).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = `mg CO2/g dry weight` ~ cc_type, data = cmin_allcc)
## 
## $cc_type
##                                 diff         lwr         upr     p adj
## oat-clover-oat           0.256684648 -1.26815870  1.78152800 0.9999406
## oat-vetch-oat            0.792561578 -0.73228177  2.31740493 0.8125330
## rye-oat                 -0.765517050 -2.29036040  0.75932630 0.8418212
## rye-clover-oat           0.745738446 -0.77910490  2.27058179 0.8615394
## rye-vetch-oat            0.629976325 -0.89486702  2.15481967 0.9466521
## radish-oat              -0.873354322 -2.39819767  0.65148903 0.7111691
## radish-oat-oat          -1.455073291 -2.97991664  0.06977006 0.0751857
## radish-rye-oat          -0.759458756 -2.28430210  0.76538459 0.8480173
## radish-vetch-oat        -0.934395154 -2.45923850  0.59044820 0.6247918
## oat-vetch-oat-clover     0.535876930 -0.98896642  2.06072028 0.9812996
## rye-oat-clover          -1.022201698 -2.54704505  0.50264165 0.4957286
## rye-clover-oat-clover    0.489053798 -1.03578955  2.01389715 0.9901349
## rye-vetch-oat-clover     0.373291677 -1.15155167  1.89813503 0.9987167
## radish-oat-clover       -1.130038970 -2.65488232  0.39480438 0.3468704
## radish-oat-oat-clover   -1.711757939 -3.23660129 -0.18691459 0.0148558
## radish-rye-oat-clover   -1.016143404 -2.54098675  0.50869994 0.5045739
## radish-vetch-oat-clover -1.191079801 -2.71592315  0.33376355 0.2737073
## rye-oat-vetch           -1.558078628 -3.08292198 -0.03323528 0.0408033
## rye-clover-oat-vetch    -0.046823132 -1.57166648  1.47802022 1.0000000
## rye-vetch-oat-vetch     -0.162585253 -1.68742860  1.36225810 0.9999989
## radish-oat-vetch        -1.665915899 -3.19075925 -0.14107255 0.0203181
## radish-oat-oat-vetch    -2.247634869 -3.77247822 -0.72279152 0.0002024
## radish-rye-oat-vetch    -1.552020334 -3.07686368 -0.02717699 0.0423612
## radish-vetch-oat-vetch  -1.726956731 -3.25180008 -0.20211338 0.0133626
## rye-clover-rye           1.511255496 -0.01358785  3.03609884 0.0542436
## rye-vetch-rye            1.395493375 -0.12934997  2.92033672 0.1043124
## radish-rye              -0.107837271 -1.63268062  1.41700608 1.0000000
## radish-oat-rye          -0.689556241 -2.21439959  0.83528711 0.9093053
## radish-rye-rye           0.006058294 -1.51878505  1.53090164 1.0000000
## radish-vetch-rye        -0.168878103 -1.69372145  1.35596525 0.9999984
## rye-vetch-rye-clover    -0.115762121 -1.64060547  1.40908123 0.9999999
## radish-rye-clover       -1.619092768 -3.14393612 -0.09424942 0.0276932
## radish-oat-rye-clover   -2.200811737 -3.72565509 -0.67596839 0.0003072
## radish-rye-rye-clover   -1.505197202 -3.03004055  0.01964615 0.0562325
## radish-vetch-rye-clover -1.680133599 -3.20497695 -0.15529025 0.0184568
## radish-rye-vetch        -1.503330647 -3.02817400  0.02151270 0.0568577
## radish-oat-rye-vetch    -2.085049616 -3.60989296 -0.56020627 0.0008344
## radish-rye-rye-vetch    -1.389435081 -2.91427843  0.13540827 0.1077236
## radish-vetch-rye-vetch  -1.564371478 -3.08921483 -0.03952813 0.0392380
## radish-oat-radish       -0.581718969 -2.10656232  0.94312438 0.9677044
## radish-rye-radish        0.113895566 -1.41094778  1.63873891 1.0000000
## radish-vetch-radish     -0.061040832 -1.58588418  1.46380252 1.0000000
## radish-rye-radish-oat    0.695614535 -0.82922881  2.22045788 0.9047488
## radish-vetch-radish-oat  0.520678137 -1.00416521  2.04552149 0.9846579
## radish-vetch-radish-rye -0.174936397 -1.69977975  1.34990695 0.9999978

Cover Crop Type (Pecan)

# perform anova for pecan
anova_CMINpecCCtype <- aov(`mg CO2/g dry weight` ~ cc_type,  data = cminPEC)
summary(anova_CMINpecCCtype)
##              Df Sum Sq Mean Sq F value Pr(>F)  
## cc_type       5  31.93   6.387   2.414 0.0411 *
## Residuals   102 269.87   2.646                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in microbial respiration between cover crop type (of the 6 types) for the pecan site (p < 0.05).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = `mg CO2/g dry weight` ~ cc_type, data = cminPEC)
## 
## $cc_type
##                              diff         lwr        upr     p adj
## oat-clover-oat         0.25668465 -1.31819119 1.83156049 0.9969662
## oat-vetch-oat          0.79256158 -0.78231426 2.36743742 0.6891349
## rye-oat               -0.76551705 -2.34039289 0.80935879 0.7197914
## rye-clover-oat         0.74573845 -0.82913740 2.32061429 0.7415541
## rye-vetch-oat          0.62997632 -0.94489952 2.20485217 0.8537166
## oat-vetch-oat-clover   0.53587693 -1.03899891 2.11075277 0.9206888
## rye-oat-clover        -1.02220170 -2.59707754 0.55267414 0.4170885
## rye-clover-oat-clover  0.48905380 -1.08582204 2.06392964 0.9451661
## rye-vetch-oat-clover   0.37329168 -1.20158416 1.94816752 0.9828667
## rye-oat-vetch         -1.55807863 -3.13295447 0.01679721 0.0542372
## rye-clover-oat-vetch  -0.04682313 -1.62169897 1.52805271 0.9999993
## rye-vetch-oat-vetch   -0.16258525 -1.73746109 1.41229059 0.9996659
## rye-clover-rye         1.51125550 -0.06362034 3.08613134 0.0676969
## rye-vetch-rye          1.39549338 -0.17938247 2.97036922 0.1132782
## rye-vetch-rye-clover  -0.11576212 -1.69063796 1.45911372 0.9999373

Cover Crop Type (Pine)

# perform anova for pine 
anova_CMINpinCCtype <- aov(`mg CO2/g dry weight` ~ cc_type,  data = cminPIN)
summary(anova_CMINpinCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type      3   5.13   1.711   1.527  0.215
## Residuals   68  76.19   1.121

The ANOVA revealed that there was not a statistically significant difference in microbial respiration between cover crop type (of the 4 types) for the pine site.

Tillage Treatment

# perform anova 
anova_cminTIL <- aov(`mg CO2/g dry weight` ~ tillage,  data = cminTIL)
summary(anova_cminTIL)
##              Df Sum Sq Mean Sq F value Pr(>F)
## tillage       1    0.4  0.3533   0.139   0.71
## Residuals   178  453.8  2.5494

The ANOVA revealed that there was not a statistically significant difference in microbial respiration between tillage treatments (minimum tillage vs. no-till).

Two-Way ANOVAs

# Performing two-way ANOVA for respiration using Agroforestry Type & Tillage
anova_CMIN_agtl <- aov(`mg CO2/g dry weight` ~ agro_type * tillage, data = cmin_nocntrl)
summary(anova_CMIN_agtl)
##                    Df Sum Sq Mean Sq F value   Pr(>F)    
## agro_type           1   71.0   71.02  33.196 3.65e-08 ***
## tillage             1    0.4    0.35   0.165   0.6850    
## agro_type:tillage   1    6.3    6.26   2.928   0.0888 .  
## Residuals         176  376.5    2.14                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of agroforestry type and tillage.

# Performing two-way ANOVA for respiration using Cover Crop Type & Tillage
anova_CMIN_cctl <- aov(`mg CO2/g dry weight` ~ cc_type * tillage, data = cmin_nocntrl)
summary(anova_CMIN_cctl)
##                  Df Sum Sq Mean Sq F value   Pr(>F)    
## cc_type           9  108.1  12.009   5.947 3.68e-07 ***
## tillage           1    0.4   0.353   0.175    0.676    
## cc_type:tillage   9   22.6   2.510   1.243    0.273    
## Residuals       160  323.1   2.020                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of cover crop type and tillage.

Enzyme Activities

Significance Summary:

The following analyses were found to be significant:

  • Agroforestry Tree Type on BG, PHOS
  • Cover Crop Type - Combined Pecan & Pine on BG, PHOS
  • Cover Crop Type - Pecan on NAG, PHOS
  • Cover Crop Type - Pine on PHOS
  • Interaction between tree type and tillage for BG, NAG, PHOS
  • Interaction between cover crop type and tillage for BG, NAG, PHOS

The following analyses were not significant:

  • Agroforestry Tree Type on NAG
  • Cover Crop Type - Combined Pecan & Pine on NAG
  • Cover Crop Type - Pecan on BG
  • Cover Crop Type - Pine on BG, NAG
  • Tillage Treatment on BG, NAG, PHOS

Agroforestry Type

# perform anova for BG by agroforestry type
anova_ACT_BG_agrotype <- aov(BG ~ agro_type,  data = activity_nocntrl)
summary(anova_ACT_BG_agrotype)
##             Df  Sum Sq Mean Sq F value   Pr(>F)    
## agro_type    1 3675557 3675557   78.77 2.13e-12 ***
## Residuals   58 2706357   46661                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in activity of the enzyme BG between agroforestry tree type (pecan vs. pine) (p < 0.001).

# perform anova for NAG by agroforestry type
anova_ACT_NAG_agrotype <- aov(NAG ~ agro_type,  data = activity_nocntrl)
summary(anova_ACT_NAG_agrotype)
##             Df  Sum Sq Mean Sq F value Pr(>F)
## agro_type    1    7810    7810   0.374  0.543
## Residuals   58 1210224   20866

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme NAG between agroforestry tree type (pecan vs. pine).

# perform anova for PHOS by agroforestry type
anova_ACT_PHOS_agrotype <- aov(PHOS ~ agro_type,  data = activity_nocntrl)
summary(anova_ACT_PHOS_agrotype)
##             Df  Sum Sq Mean Sq F value   Pr(>F)    
## agro_type    1 5984926 5984926   40.77 3.13e-08 ***
## Residuals   58 8513787  146789                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in activity of the enzyme PHOS between agroforestry tree type (pecan vs. pine) (p < 0.001).

Visualizing all enzymes together on the same scale:

Cover Crop Type (Combined)

# perform anova for BG 
anova_ACT_BG_CCtype <- aov(BG ~ cc_type,  data = activity_nocntrl)
summary(anova_ACT_BG_CCtype)
##             Df  Sum Sq Mean Sq F value   Pr(>F)    
## cc_type      9 4096020  455113   9.955 1.48e-08 ***
## Residuals   50 2285893   45718                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in activity of the enzyme BG between cover crop type when considering both sites (pecan and pine) combined (p < 0.001).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = BG ~ cc_type, data = activity_nocntrl)
## 
## $cc_type
##                                diff         lwr         upr     p adj
## oat-clover-oat            87.792927  -320.85173  496.437589 0.9993178
## oat-vetch-oat             91.425614  -317.21905  500.070276 0.9990585
## radish-oat              -556.454702  -965.09936 -147.810041 0.0015050
## radish-oat-oat          -330.662999  -739.30766   77.981663 0.2104587
## radish-rye-oat          -332.644807  -741.28947   75.999854 0.2039012
## radish-vetch-oat        -393.654478  -802.29914   14.990183 0.0677776
## rye-oat                  224.351525  -184.29314  632.996187 0.7213328
## rye-clover-oat           176.494048  -232.15061  585.138709 0.9118013
## rye-vetch-oat             31.128892  -377.51577  439.773554 0.9999999
## oat-vetch-oat-clover       3.632687  -405.01197  412.277349 1.0000000
## radish-oat-clover       -644.247630 -1052.89229 -235.602968 0.0001413
## radish-oat-oat-clover   -418.455926  -827.10059   -9.811265 0.0407166
## radish-rye-oat-clover   -420.437734  -829.08240  -11.793073 0.0390394
## radish-vetch-oat-clover -481.447405  -890.09207  -72.802744 0.0098246
## rye-oat-clover           136.558598  -272.08606  545.203260 0.9818123
## rye-clover-oat-clover     88.701120  -319.94354  497.345782 0.9992594
## rye-vetch-oat-clover     -56.664035  -465.30870  351.980626 0.9999821
## radish-oat-vetch        -647.880317 -1056.52498 -239.235655 0.0001277
## radish-oat-oat-vetch    -422.088613  -830.73327  -13.443952 0.0376897
## radish-rye-oat-vetch    -424.070421  -832.71508  -15.425760 0.0361246
## radish-vetch-oat-vetch  -485.080092  -893.72475  -76.435431 0.0090079
## rye-oat-vetch            132.925911  -275.71875  541.570573 0.9848511
## rye-clover-oat-vetch      85.068433  -323.57623  493.713095 0.9994701
## rye-vetch-oat-vetch      -60.296722  -468.94138  348.347939 0.9999695
## radish-oat-radish        225.791703  -182.85296  634.436365 0.7141015
## radish-rye-radish        223.809895  -184.83477  632.454557 0.7240365
## radish-vetch-radish      162.800224  -245.84444  571.444886 0.9444764
## rye-radish               780.806228   372.16157 1189.450889 0.0000029
## rye-clover-radish        732.948750   324.30409 1141.593411 0.0000116
## rye-vetch-radish         587.583594   178.93893  996.228256 0.0006615
## radish-rye-radish-oat     -1.981808  -410.62647  406.662853 1.0000000
## radish-vetch-radish-oat  -62.991479  -471.63614  345.653182 0.9999559
## rye-radish-oat           555.014524   146.36986  963.659186 0.0015625
## rye-clover-radish-oat    507.157047    98.51239  915.801708 0.0052644
## rye-vetch-radish-oat     361.791891   -46.85277  770.436553 0.1240609
## radish-vetch-radish-rye  -61.009671  -469.65433  347.634990 0.9999663
## rye-radish-rye           556.996332   148.35167  965.640994 0.0014839
## rye-clover-radish-rye    509.138855   100.49419  917.783516 0.0050127
## rye-vetch-radish-rye     363.773699   -44.87096  772.418361 0.1196961
## rye-radish-vetch         618.006003   209.36134 1026.650665 0.0002907
## rye-clover-radish-vetch  570.148526   161.50386  978.793187 0.0010511
## rye-vetch-radish-vetch   424.783370    16.13871  833.428032 0.0355760
## rye-clover-rye           -47.857478  -456.50214  360.787184 0.9999958
## rye-vetch-rye           -193.222633  -601.86729  215.422028 0.8580500
## rye-vetch-rye-clover    -145.365155  -554.00982  263.279506 0.9725259

# perform anova for NAG 
anova_ACT_NAG_CCtype <- aov(NAG ~ cc_type,  data = activity_nocntrl)
summary(anova_ACT_NAG_CCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)  
## cc_type      9 295300   32811   1.778 0.0961 .
## Residuals   50 922734   18455                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme NAG between cover crop type when considering both sites (pecan and pine) combined.

# perform anova for PHOS
anova_ACT_PHOS_CCtype <- aov(PHOS ~ cc_type,  data = activity_nocntrl)
summary(anova_ACT_PHOS_CCtype)
##             Df   Sum Sq Mean Sq F value   Pr(>F)    
## cc_type      9 10555380 1172820   14.87 2.29e-11 ***
## Residuals   50  3943332   78867                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in activity of the enzyme PHOS between cover crop type when considering both sites (pecan and pine) combined (p < 0.001).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = PHOS ~ cc_type, data = activity_nocntrl)
## 
## $cc_type
##                                diff          lwr         upr     p adj
## oat-clover-oat            457.33191   -79.390259  994.054077 0.1575282
## oat-vetch-oat              40.94936  -495.772807  577.671530 0.9999999
## radish-oat                339.65369  -197.068478  876.375859 0.5395788
## radish-oat-oat           1104.51468   567.792512 1641.236849 0.0000005
## radish-rye-oat           1062.49458   525.772413 1599.216749 0.0000013
## radish-vetch-oat          898.14824   361.426074 1434.870410 0.0000467
## rye-oat                   574.68084    37.958667 1111.403004 0.0269435
## rye-clover-oat            295.26278  -241.459386  831.984951 0.7190649
## rye-vetch-oat            -129.12330  -665.845470  407.598867 0.9983380
## oat-vetch-oat-clover     -416.38255  -953.104715  120.339621 0.2596585
## radish-oat-clover        -117.67822  -654.400386  419.043950 0.9991978
## radish-oat-oat-clover     647.18277   110.460603 1183.904940 0.0074890
## radish-rye-oat-clover     605.16267    68.440504 1141.884840 0.0159591
## radish-vetch-oat-clover   440.81633   -95.905835  977.538501 0.1943207
## rye-oat-clover            117.34893  -419.373242  654.071095 0.9992155
## rye-clover-oat-clover    -162.06913  -698.791295  374.653042 0.9909802
## rye-vetch-oat-clover     -586.45521 -1123.177379  -49.733042 0.0220683
## radish-oat-vetch          298.70433  -238.017839  835.426497 0.7058304
## radish-oat-oat-vetch     1063.56532   526.843151 1600.287487 0.0000013
## radish-rye-oat-vetch     1021.54522   484.823051 1558.267387 0.0000032
## radish-vetch-oat-vetch    857.19888   320.476712 1393.921048 0.0001119
## rye-oat-vetch             533.73147    -2.990694 1070.453642 0.0524046
## rye-clover-oat-vetch      254.31342  -282.408747  791.035589 0.8565644
## rye-vetch-oat-vetch      -170.07266  -706.794831  366.649505 0.9873504
## radish-oat-radish         764.86099   228.138822 1301.583158 0.0007608
## radish-rye-radish         722.84089   186.118722 1259.563058 0.0017636
## radish-vetch-radish       558.49455    21.772383 1095.216719 0.0352425
## rye-radish                235.02714  -301.695023  771.749313 0.9048896
## rye-clover-radish         -44.39091  -581.113076  492.331260 0.9999998
## rye-vetch-radish         -468.77699 -1005.499160   67.945176 0.1353519
## radish-rye-radish-oat     -42.02010  -578.742268  494.702068 0.9999999
## radish-vetch-radish-oat  -206.36644  -743.088607  330.355730 0.9551738
## rye-radish-oat           -529.83384 -1066.556013    6.888323 0.0556903
## rye-clover-radish-oat    -809.25190 -1345.974066 -272.529730 0.0003059
## rye-vetch-radish-oat    -1233.63798 -1770.360150 -696.915814 0.0000000
## radish-vetch-radish-rye  -164.34634  -701.068507  372.375829 0.9900442
## rye-radish-rye           -487.81375 -1024.535913   48.908423 0.1040335
## rye-clover-radish-rye    -767.23180 -1303.953966 -230.509630 0.0007251
## rye-vetch-radish-rye    -1191.61788 -1728.340050 -654.895714 0.0000001
## rye-radish-vetch         -323.46741  -860.189575  213.254762 0.6063429
## rye-clover-radish-vetch  -602.88546 -1139.607628  -66.163291 0.0166086
## rye-vetch-radish-vetch  -1027.27154 -1563.993712 -490.549375 0.0000028
## rye-clover-rye           -279.41805  -816.140221  257.304115 0.7771198
## rye-vetch-rye            -703.80414 -1240.526305 -167.081969 0.0025602
## rye-vetch-rye-clover     -424.38608  -961.108252  112.336084 0.2368036

Visualizing all enzymes together on the same scale:

Cover Crop Type (Pecan)

# perform anova for BG for pecan 
anova_act_BG_pecCCtype <- aov(BG ~ cc_type,  data = act_agPEC)
summary(anova_act_BG_pecCCtype)
##             Df  Sum Sq Mean Sq F value Pr(>F)
## cc_type      5  217557   43511    0.76  0.586
## Residuals   30 1718148   57272

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme BG between cover crop type (of the 6 types) for the pecan site.

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = BG ~ cc_type, data = act_agPEC)
## 
## $cc_type
##                              diff       lwr      upr     p adj
## oat-clover-oat          87.792927 -332.4596 508.0455 0.9873361
## oat-vetch-oat           91.425614 -328.8269 511.6782 0.9848124
## rye-oat                224.351525 -195.9010 644.6041 0.5900028
## rye-clover-oat         176.494048 -243.7585 596.7466 0.7946582
## rye-vetch-oat           31.128892 -389.1237 451.3814 0.9999113
## oat-vetch-oat-clover     3.632687 -416.6199 423.8852 1.0000000
## rye-oat-clover         136.558598 -283.6939 556.8111 0.9180826
## rye-clover-oat-clover   88.701120 -331.5514 508.9537 0.9867362
## rye-vetch-oat-clover   -56.664035 -476.9166 363.5885 0.9983562
## rye-oat-vetch          132.925911 -287.3266 553.1785 0.9262587
## rye-clover-oat-vetch    85.068433 -335.1841 505.3210 0.9890166
## rye-vetch-oat-vetch    -60.296722 -480.5493 359.9558 0.9977887
## rye-clover-rye         -47.857478 -468.1100 372.3951 0.9992716
## rye-vetch-rye         -193.222633 -613.4752 227.0299 0.7275811
## rye-vetch-rye-clover  -145.365155 -565.6177 274.8874 0.8960663

# perform anova for NAG for pecan 
anova_act_NAG_pecCCtype <- aov(NAG ~ cc_type,  data = act_agPEC)
summary(anova_act_NAG_pecCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)  
## cc_type      5 247391   49478   3.159 0.0208 *
## Residuals   30 469951   15665                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in activity of the enzyme NAG between cover crop type (of the 6 types) for the pecan site (p < 0.05).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = NAG ~ cc_type, data = act_agPEC)
## 
## $cc_type
##                              diff         lwr       upr     p adj
## oat-clover-oat         117.352561 -102.436667 337.14179 0.5898448
## oat-vetch-oat          106.580054 -113.209173 326.36928 0.6821303
## rye-oat                196.852704  -22.936524 416.64193 0.0997692
## rye-clover-oat         214.708682   -5.080545 434.49791 0.0585667
## rye-vetch-oat            6.995784 -212.793444 226.78501 0.9999987
## oat-vetch-oat-clover   -10.772507 -230.561735 209.01672 0.9999885
## rye-oat-clover          79.500143 -140.289085 299.28937 0.8774162
## rye-clover-oat-clover   97.356121 -122.433107 317.14535 0.7567825
## rye-vetch-oat-clover  -110.356778 -330.146006 109.43245 0.6501483
## rye-oat-vetch           90.272650 -129.516578 310.06188 0.8091463
## rye-clover-oat-vetch   108.128628 -111.660600 327.91786 0.6690888
## rye-vetch-oat-vetch    -99.584271 -319.373499 120.20496 0.7393208
## rye-clover-rye          17.855978 -201.933249 237.64521 0.9998602
## rye-vetch-rye         -189.856921 -409.646148  29.93231 0.1216047
## rye-vetch-rye-clover  -207.712899 -427.502127  12.07633 0.0724811

# perform anova for PHOS for pecan 
anova_act_PHOS_pecCCtype <- aov(PHOS ~ cc_type,  data = act_agPEC)
summary(anova_act_PHOS_pecCCtype)
##             Df  Sum Sq Mean Sq F value   Pr(>F)    
## cc_type      5 2334269  466854   11.74 2.42e-06 ***
## Residuals   30 1193389   39780                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in activity of the enzyme PHOS between cover crop type (of the 6 types) for the pecan site (p < 0.05).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = PHOS ~ cc_type, data = act_agPEC)
## 
## $cc_type
##                             diff         lwr        upr     p adj
## oat-clover-oat         457.33191   107.08757  807.57625 0.0050386
## oat-vetch-oat           40.94936  -309.29498  391.19370 0.9991725
## rye-oat                574.68084   224.43650  924.92517 0.0003184
## rye-clover-oat         295.26278   -54.98156  645.50712 0.1378947
## rye-vetch-oat         -129.12330  -479.36764  221.12104 0.8686687
## oat-vetch-oat-clover  -416.38255  -766.62689  -66.13821 0.0125790
## rye-oat-clover         117.34893  -232.89541  467.59326 0.9078541
## rye-clover-oat-clover -162.06913  -512.31346  188.17521 0.7223435
## rye-vetch-oat-clover  -586.45521  -936.69955 -236.21087 0.0002399
## rye-oat-vetch          533.73147   183.48714  883.97581 0.0008475
## rye-clover-oat-vetch   254.31342   -95.93092  604.55776 0.2636466
## rye-vetch-oat-vetch   -170.07266  -520.31700  180.17167 0.6809070
## rye-clover-rye        -279.41805  -629.66239   70.82628 0.1793919
## rye-vetch-rye         -703.80414 -1054.04847 -353.55980 0.0000142
## rye-vetch-rye-clover  -424.38608  -774.63042  -74.14175 0.0105509

Visualizing all enzymes together on the same scale:

Cover Crop Type (Pine)

# perform anova for BG for pine 
anova_act_BG_pinCCtype <- aov(BG ~ cc_type,  data = act_agPIN)
summary(anova_act_BG_pinCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)  
## cc_type      3 202906   67635   2.383 0.0998 .
## Residuals   20 567745   28387                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme BG between cover crop type (of the 6 types) for the pine site.

# perform anova for NAG for pine 
anova_act_NAG_pinCCtype <- aov(NAG ~ cc_type,  data = act_agPIN)
summary(anova_act_NAG_pinCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type      3  40099   13366    0.59  0.628
## Residuals   20 452783   22639

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme NAG between cover crop type (of the 6 types) for the pine site.

# perform anova for PHOS for pine 
anova_act_PHOS_pinCCtype <- aov(PHOS ~ cc_type,  data = act_agPIN)
summary(anova_act_PHOS_pinCCtype)
##             Df  Sum Sq Mean Sq F value Pr(>F)   
## cc_type      3 2236185  745395   5.421 0.0068 **
## Residuals   20 2749943  137497                  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in activity of the enzyme PHOS between cover crop type (of the 6 types) for the pine site (p < 0.01).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = PHOS ~ cc_type, data = act_agPIN)
## 
## $cc_type
##                              diff        lwr       upr     p adj
## radish-oat-radish        764.8610  165.65077 1364.0712 0.0094704
## radish-rye-radish        722.8409  123.63067 1322.0511 0.0146260
## radish-vetch-radish      558.4946  -40.71567 1157.7048 0.0732424
## radish-rye-radish-oat    -42.0201 -641.23032  557.1901 0.9972300
## radish-vetch-radish-oat -206.3664 -805.57666  392.8438 0.7710296
## radish-vetch-radish-rye -164.3463 -763.55656  434.8639 0.8680051

Visualizing all enzymes together on the same scale:

Tillage Treatment

# perform anova for BG
anova_act_BG_TIL <- aov(BG ~ tillage,  data = act_agTIL)
summary(anova_act_BG_TIL)
##             Df  Sum Sq Mean Sq F value Pr(>F)
## tillage      1   58738   58738   0.539  0.466
## Residuals   58 6323175  109020

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme BG between tillage treatments (minimum tillage vs. no-till).

# perform anova for NAG
anova_act_NAG_TIL <- aov(NAG ~ tillage,  data = act_agTIL)
summary(anova_act_NAG_TIL)
##             Df  Sum Sq Mean Sq F value Pr(>F)
## tillage      1    3749    3749   0.179  0.674
## Residuals   58 1214285   20936

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme NAG between tillage treatments (minimum tillage vs. no-till).

# perform anova for PHOS
anova_act_PHOS_TIL <- aov(PHOS ~ tillage,  data = act_agTIL)
summary(anova_act_PHOS_TIL)
##             Df   Sum Sq Mean Sq F value Pr(>F)
## tillage      1    23466   23466   0.094   0.76
## Residuals   58 14475246  249573

The ANOVA revealed that there was not a statistically significant difference in activity of the enzyme PHOS between tillage treatments (minimum tillage vs. no-till).

Visualizing all enzymes together on the same scale:

Two-Way ANOVAs

# Performing two-way ANOVA for BG activity using Agroforestry Type & Tillage
anova_ACT_BG_agtl <- aov(BG ~ agro_type * tillage, data = activity_nocntrl)
summary(anova_ACT_BG_agtl)
##                   Df  Sum Sq Mean Sq F value   Pr(>F)    
## agro_type          1 3675557 3675557 111.898 5.73e-15 ***
## tillage            1   58738   58738   1.788    0.187    
## agro_type:tillage  1  808159  808159  24.603 6.91e-06 ***
## Residuals         56 1839460   32847                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

BG: A two-way ANOVA showed that there was a statistically significant interaction between the effects of agroforestry type and tillage (p < 0.001).

# Performing two-way ANOVA for BG activity using Cover Crop Type & Tillage
anova_ACT_BG_cctl <- aov(BG ~ cc_type * tillage, data = activity_nocntrl)
summary(anova_ACT_BG_cctl)
##                 Df  Sum Sq Mean Sq F value   Pr(>F)    
## cc_type          9 4096020  455113  38.392  < 2e-16 ***
## tillage          1   58738   58738   4.955   0.0317 *  
## cc_type:tillage  9 1752974  194775  16.430 7.38e-11 ***
## Residuals       40  474181   11855                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

BG: A two-way ANOVA showed that there was a statistically significant interaction between the effects of cover crop type and tillage (p < 0.001).

# Performing two-way ANOVA for NAG activity using Agroforestry Type & Tillage
anova_ACT_NAG_agtl <- aov(NAG ~ agro_type * tillage, data = activity_nocntrl)
summary(anova_ACT_NAG_agtl)
##                   Df Sum Sq Mean Sq F value   Pr(>F)    
## agro_type          1   7810    7810   0.453 0.503643    
## tillage            1   3749    3749   0.218 0.642752    
## agro_type:tillage  1 241210  241210  13.994 0.000433 ***
## Residuals         56 965265   17237                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

NAG: A two-way ANOVA showed that there was a statistically significant interaction between the effects of agroforestry type and tillage (p < 0.001).

# Performing two-way ANOVA for NAG activity using Cover Crop Type & Tillage
anova_ACT_NAG_cctl <- aov(NAG ~ cc_type * tillage, data = activity_nocntrl)
summary(anova_ACT_NAG_cctl)
##                 Df Sum Sq Mean Sq F value   Pr(>F)    
## cc_type          9 295300   32811   8.133 9.78e-07 ***
## tillage          1   3749    3749   0.929    0.341    
## cc_type:tillage  9 757617   84180  20.866 1.82e-12 ***
## Residuals       40 161368    4034                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

NAG: A two-way ANOVA showed that there was a statistically significant interaction between the effects of cover crop type and tillage (p < 0.001).

# Performing two-way ANOVA for PHOS activity using Agroforestry Type & Tillage
anova_ACT_PHOS_agtl <- aov(PHOS ~ agro_type * tillage, data = activity_nocntrl)
summary(anova_ACT_PHOS_agtl)
##                   Df  Sum Sq Mean Sq F value   Pr(>F)    
## agro_type          1 5984926 5984926  44.613 1.17e-08 ***
## tillage            1   23466   23466   0.175  0.67737    
## agro_type:tillage  1  977860  977860   7.289  0.00916 ** 
## Residuals         56 7512461  134151                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

PHOS: A two-way ANOVA showed that there was a statistically significant interaction between the effects of agroforestry type and tillage (p < 0.01).

# Performing two-way ANOVA for PHOS activity using Cover Crop Type & Tillage
anova_ACT_PHOS_cctl <- aov(PHOS ~ cc_type * tillage, data = activity_nocntrl)
summary(anova_ACT_PHOS_cctl)
##                 Df   Sum Sq Mean Sq F value   Pr(>F)    
## cc_type          9 10555380 1172820  40.944  < 2e-16 ***
## tillage          1    23466   23466   0.819    0.371    
## cc_type:tillage  9  2774085  308232  10.761 2.95e-08 ***
## Residuals       40  1145781   28645                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

PHOS: A two-way ANOVA showed that there was a statistically significant interaction between the effects of cover crop type and tillage (p < 0.001).

Necromass

Significance Summary:

The following analyses were found to be significant:

  • Cover Crop Type - Pecan (for Total, Fungal, and Bacterial)

The following analyses were not significant:

  • Agroforestry Type (for Total, Fungal, and Bacterial)
  • Cover Crop Type - Combined Pecan & Pine (for Total, Fungal, and Bacterial)
  • Cover Crop Type - Pine (for Total, Fungal, and Bacterial)
  • Tillage (for Total, Fungal, and Bacterial)
  • No interaction between tree type and tillage (for Total, Fungal, and Bacterial)

Agroforestry Type

Total Necromass

# perform anova for total necromass
anova_NECagrotype <- aov(MicrobialResidualC_mg_g ~ agro_type,  data = nec_nocntrl)
summary(anova_NECagrotype)
##             Df  Sum Sq  Mean Sq F value Pr(>F)
## agro_type    1 0.00434 0.004336   0.319  0.579
## Residuals   18 0.24457 0.013587

The ANOVA revealed that there was not a statistically significant difference in total necromass between agroforestry tree type (pecan vs. pine).

Fungal Necromass

# perform anova for fungal necromass
anova_NECFagrotype <- aov(FungalC_mg_g ~ agro_type,  data = nec_nocntrl)
summary(anova_NECFagrotype)
##             Df  Sum Sq  Mean Sq F value Pr(>F)
## agro_type    1 0.00001 0.000011   0.002  0.969
## Residuals   18 0.12798 0.007110

The ANOVA revealed that there was not a statistically significant difference in fungal necromass between agroforestry tree type (pecan vs. pine).

Bacterial Necromass

# perform anova for bacterial necromass
anova_NECBagrotype <- aov(BacterialC_mg_g ~ agro_type,  data = nec_nocntrl)
summary(anova_NECBagrotype)
##             Df   Sum Sq  Mean Sq F value Pr(>F)  
## agro_type    1 0.003907 0.003907   3.143 0.0932 .
## Residuals   18 0.022380 0.001243                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was not a statistically significant difference in bacterial necromass between agroforestry tree type (pecan vs. pine).

Cover Crop Type (Combined)

Total Necromass

# perform anova for combined
anova_NECCCtype <- aov(MicrobialResidualC_mg_g ~ cc_type,  data = necdata)
summary(anova_NECCCtype)
##             Df Sum Sq Mean Sq F value Pr(>F)
## cc_type     10 0.1914 0.01914   0.996  0.499
## Residuals   11 0.2114 0.01921

The ANOVA revealed that there was not a statistically significant difference in total necromass between cover crop type when considering both sites combined.

Fungal Necromass

# perform anova for combined
anova_NECFCCtype <- aov(FungalC_mg_g ~ cc_type,  data = necdata)
summary(anova_NECFCCtype)
##             Df  Sum Sq  Mean Sq F value Pr(>F)
## cc_type     10 0.09917 0.009917   0.873  0.581
## Residuals   11 0.12502 0.011365

The ANOVA revealed that there was not a statistically significant difference in fungal necromass between cover crop type when considering both sites combined.

Bacterial Necromass

# perform anova for combined
anova_NECBCCtype <- aov(BacterialC_mg_g ~ cc_type,  data = necdata)
summary(anova_NECBCCtype)
##             Df  Sum Sq  Mean Sq F value Pr(>F)
## cc_type     10 0.02008 0.002008   1.701  0.198
## Residuals   11 0.01299 0.001181

The ANOVA revealed that there was not a statistically significant difference in bacterial necromass between cover crop type when considering both sites combined.

Cover Crop Type (Pecan)

Total Necromass

# perform anova for pecan
anova_NECpecCCtype <- aov(MicrobialResidualC_mg_g ~ cc_type,  data = necPEC)
summary(anova_NECpecCCtype)
##             Df  Sum Sq  Mean Sq F value Pr(>F)  
## cc_type      5 0.11489 0.022978   5.614  0.029 *
## Residuals    6 0.02456 0.004093                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in total necromass between cover crop type (of the 6 types) for the pecan site (p < 0.05).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = MicrobialResidualC_mg_g ~ cc_type, data = necPEC)
## 
## $cc_type
##                              diff          lwr         upr     p adj
## oat-clover-oat         0.26083978  0.006230636  0.51544892 0.0451230
## oat-vetch-oat          0.08341985 -0.171189287  0.33802899 0.7753391
## rye-oat               -0.05465415 -0.309263291  0.19995499 0.9449987
## rye-clover-oat         0.08214542 -0.172463717  0.33675456 0.7848482
## rye-vetch-oat          0.09494528 -0.159663859  0.34955442 0.6854201
## oat-vetch-oat-clover  -0.17741992 -0.432029063  0.07718922 0.1889825
## rye-oat-clover        -0.31549393 -0.570103067 -0.06088479 0.0191415
## rye-clover-oat-clover -0.17869435 -0.433303493  0.07591479 0.1848127
## rye-vetch-oat-clover  -0.16589449 -0.420503635  0.08871465 0.2310308
## rye-oat-vetch         -0.13807400 -0.392683145  0.11653514 0.3696387
## rye-clover-oat-vetch  -0.00127443 -0.255883571  0.25333471 1.0000000
## rye-vetch-oat-vetch    0.01152543 -0.243083712  0.26613457 0.9999568
## rye-clover-rye         0.13679957 -0.117809567  0.39140871 0.3773608
## rye-vetch-rye          0.14959943 -0.105009708  0.40420857 0.3053704
## rye-vetch-rye-clover   0.01279986 -0.241809282  0.26740900 0.9999276

Fungal Necromass

# perform anova for pecan
anova_NECFpecCCtype <- aov(FungalC_mg_g ~ cc_type,  data = necPEC)
summary(anova_NECFpecCCtype)
##             Df  Sum Sq  Mean Sq F value Pr(>F)  
## cc_type      5 0.06035 0.012071   5.152 0.0352 *
## Residuals    6 0.01406 0.002343                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in fungal necromass between cover crop type (of the 6 types) for the pecan site (p < 0.05).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = FungalC_mg_g ~ cc_type, data = necPEC)
## 
## $cc_type
##                               diff        lwr         upr     p adj
## oat-clover-oat         0.196318486  0.0036745  0.38896247 0.0461523
## oat-vetch-oat          0.068408469 -0.1242355  0.26105246 0.7214169
## rye-oat               -0.027873481 -0.2205175  0.16477051 0.9891946
## rye-clover-oat         0.074926009 -0.1177180  0.26757000 0.6527267
## rye-vetch-oat          0.059594166 -0.1330498  0.25223815 0.8094600
## oat-vetch-oat-clover  -0.127910017 -0.3205540  0.06473397 0.2186983
## rye-oat-clover        -0.224191967 -0.4168360 -0.03154798 0.0256357
## rye-clover-oat-clover -0.121392477 -0.3140365  0.07125151 0.2538653
## rye-vetch-oat-clover  -0.136724320 -0.3293683  0.05591967 0.1784237
## rye-oat-vetch         -0.096281950 -0.2889259  0.09636204 0.4390426
## rye-clover-oat-vetch   0.006517540 -0.1861264  0.19916153 0.9999898
## rye-vetch-oat-vetch   -0.008814303 -0.2014583  0.18382968 0.9999545
## rye-clover-rye         0.102799490 -0.0898445  0.29544348 0.3830977
## rye-vetch-rye          0.087467647 -0.1051763  0.28011163 0.5227219
## rye-vetch-rye-clover  -0.015331843 -0.2079758  0.17731214 0.9993222

Bacterial Necromass

# perform anova for pecan
anova_NECBpecCCtype <- aov(BacterialC_mg_g ~ cc_type,  data = necPEC)
summary(anova_NECBpecCCtype)
##             Df   Sum Sq   Mean Sq F value Pr(>F)  
## cc_type      5 0.009786 0.0019572   5.342 0.0325 *
## Residuals    6 0.002198 0.0003664                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The ANOVA revealed that there was a statistically significant difference in bacterial necromass between cover crop type (of the 6 types) for the pecan site (p < 0.05).

Results of Tukey HSD test and visualization:

##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = BacterialC_mg_g ~ cc_type, data = necPEC)
## 
## $cc_type
##                               diff         lwr         upr     p adj
## oat-clover-oat         0.064521290 -0.01165648  0.14069906 0.0968423
## oat-vetch-oat          0.015011384 -0.06116638  0.09118915 0.9605475
## rye-oat               -0.026780670 -0.10295844  0.04939710 0.7285166
## rye-clover-oat         0.007219415 -0.06895835  0.08339718 0.9984424
## rye-vetch-oat          0.035351116 -0.04082665  0.11152888 0.5036867
## oat-vetch-oat-clover  -0.049509906 -0.12568767  0.02666786 0.2327084
## rye-oat-clover        -0.091301960 -0.16747973 -0.01512419 0.0223758
## rye-clover-oat-clover -0.057301876 -0.13347964  0.01887589 0.1475845
## rye-vetch-oat-clover  -0.029170174 -0.10534794  0.04700759 0.6650019
## rye-oat-vetch         -0.041792054 -0.11796982  0.03438571 0.3600720
## rye-clover-oat-vetch  -0.007791970 -0.08396974  0.06838580 0.9977700
## rye-vetch-oat-vetch    0.020339732 -0.05583804  0.09651750 0.8800008
## rye-clover-rye         0.034000084 -0.04217768  0.11017785 0.5376017
## rye-vetch-rye          0.062131786 -0.01404598  0.13830955 0.1112640
## rye-vetch-rye-clover   0.028131701 -0.04804607  0.10430947 0.6927701

Cover Crop Type (Pine)

Total Necromass

# perform anova for pine
anova_NECpinCCtype <- aov(MicrobialResidualC_mg_g ~ cc_type,  data = necPIN)
summary(anova_NECpinCCtype)
##             Df  Sum Sq Mean Sq F value Pr(>F)
## cc_type      3 0.04128 0.01376   0.862   0.53
## Residuals    4 0.06385 0.01596

The ANOVA revealed that there was not a statistically significant difference in total necromass between cover crop type (of the 4 types) for the pine site.

Fungal Necromass

# perform anova for pine
anova_NECFpinCCtype <- aov(FungalC_mg_g ~ cc_type,  data = necPIN)
summary(anova_NECFpinCCtype)
##             Df  Sum Sq  Mean Sq F value Pr(>F)
## cc_type      3 0.01781 0.005937   0.664  0.616
## Residuals    4 0.03575 0.008938

The ANOVA revealed that there was not a statistically significant difference in fungal necromass between cover crop type (of the 4 types) for the pine site.

Bacterial Necromass

# perform anova for pine
anova_NECBpinCCtype <- aov(BacterialC_mg_g ~ cc_type,  data = necPIN)
summary(anova_NECBpinCCtype)
##             Df   Sum Sq  Mean Sq F value Pr(>F)
## cc_type      3 0.005444 0.001814   1.466   0.35
## Residuals    4 0.004952 0.001238

The ANOVA revealed that there was not a statistically significant difference in bacterial necromass between cover crop type (of the 4 types) for the pine site.

Tillage Treatment

Total Necromass

# perform anova
anova_necTIL <- aov(MicrobialResidualC_mg_g ~ tillage,  data = necTIL)
summary(anova_necTIL)
##             Df  Sum Sq Mean Sq F value Pr(>F)
## tillage      1 0.00052 0.00052   0.038  0.848
## Residuals   18 0.24839 0.01380

The ANOVA revealed that there was not a statistically significant difference in total necromass between tillage treatments (minimum tillage vs. no-till).

Fungal Necromass

# perform anova
anova_necFTIL <- aov(FungalC_mg_g ~ tillage,  data = necTIL)
summary(anova_necFTIL)
##             Df  Sum Sq  Mean Sq F value Pr(>F)
## tillage      1 0.00033 0.000332   0.047  0.831
## Residuals   18 0.12766 0.007092

The ANOVA revealed that there was not a statistically significant difference in total necromass between tillage treatments (minimum tillage vs. no-till).

Bacterial Necromass

# perform anova
anova_necBTIL <- aov(BacterialC_mg_g ~ tillage,  data = necTIL)
summary(anova_necBTIL)
##             Df   Sum Sq  Mean Sq F value Pr(>F)
## tillage      1 0.000021 0.000021   0.014  0.906
## Residuals   18 0.026266 0.001459

The ANOVA revealed that there was not a statistically significant difference in bacterial necromass between tillage treatments (minimum tillage vs. no-till).

Two-Way ANOVAs

Total Necromass

# Performing two-way ANOVA for total necromass using Agroforestry Type & Tillage
anova_NECt_agtl <- aov(MicrobialResidualC_mg_g ~ agro_type * tillage, data = nec_nocntrl)
summary(anova_NECt_agtl)
##                   Df  Sum Sq  Mean Sq F value Pr(>F)
## agro_type          1 0.00434 0.004336   0.288  0.599
## tillage            1 0.00052 0.000520   0.034  0.855
## agro_type:tillage  1 0.00285 0.002851   0.189  0.669
## Residuals         16 0.24120 0.015075

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of agroforestry type and tillage.

# Performing two-way ANOVA for total necromass using Cover Crop Type & Tillage
anova_NECt_cctl <- aov(MicrobialResidualC_mg_g ~ cc_type * tillage, data = nec_nocntrl)
summary(anova_NECt_cctl)
##                 Df  Sum Sq  Mean Sq
## cc_type          9 0.16050 0.017833
## tillage          1 0.00052 0.000520
## cc_type:tillage  9 0.08788 0.009765

A two-way ANOVA was not able to be performed for cover crop type and tillage, likely due to a lack of replication / variability (only one season of data, so only 1 observation for each cover crop / tillage combination).

Fungal Necromass

# Performing two-way ANOVA for fungal necromass using Agroforestry Type & Tillage
anova_NECf_agtl <- aov(FungalC_mg_g ~ agro_type * tillage, data = nec_nocntrl)
summary(anova_NECf_agtl)
##                   Df  Sum Sq  Mean Sq F value Pr(>F)
## agro_type          1 0.00001 0.000011   0.001  0.971
## tillage            1 0.00033 0.000332   0.042  0.841
## agro_type:tillage  1 0.00033 0.000329   0.041  0.841
## Residuals         16 0.12732 0.007957

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of agroforestry type and tillage.

# Performing two-way ANOVA for fungal necromass using Cover Crop Type & Tillage
anova_NECf_cctl <- aov(FungalC_mg_g ~ cc_type * tillage, data = nec_nocntrl)
summary(anova_NECf_cctl)
##                 Df  Sum Sq  Mean Sq
## cc_type          9 0.07818 0.008686
## tillage          1 0.00033 0.000332
## cc_type:tillage  9 0.04948 0.005498

A two-way ANOVA was not able to be performed for cover crop type and tillage, likely due to a lack of replication / variability (only one season of data, so only 1 observation for each cover crop / tillage combination).

Bacterial Necromass

# Performing two-way ANOVA for bacterial necromass using Agroforestry Type & Tillage
anova_NECb_agtl <- aov(BacterialC_mg_g ~ agro_type * tillage, data = nec_nocntrl)
summary(anova_NECb_agtl)
##                   Df   Sum Sq  Mean Sq F value Pr(>F)
## agro_type          1 0.003907 0.003907   2.961  0.105
## tillage            1 0.000021 0.000021   0.016  0.901
## agro_type:tillage  1 0.001243 0.001243   0.942  0.346
## Residuals         16 0.021116 0.001320

A two-way ANOVA showed that there was not a statistically significant interaction between the effects of agroforestry type and tillage.

# Performing two-way ANOVA for bacterial necromass using Cover Crop Type & Tillage
anova_NECb_cctl <- aov(BacterialC_mg_g ~ cc_type * tillage, data = nec_nocntrl)
summary(anova_NECb_cctl)
##                 Df   Sum Sq   Mean Sq
## cc_type          9 0.019137 0.0021263
## tillage          1 0.000021 0.0000210
## cc_type:tillage  9 0.007129 0.0007922

A two-way ANOVA was not able to be performed for cover crop type and tillage, likely due to a lack of replication / variability (only one season of data, so only 1 observation for each cover crop / tillage combination).

Summary Statistics

Corrplot

This first correlation matrix using corrplot( ) uses data from only the third season (because we only have necromass data for the third season, so otherwise it would have to be removed):

This next correlation matrix using corrplot( ) uses data from all seasons (so necromass has been removed):

Scatter Plots

This first scatter plot uses the function chart.Correlation( ) with data from all 3 seasons, without necromass being removed (this means that there are many NAs in the data from the first 2 seasons, but the function still seems to work):

This next scatter plot uses the function chart.Correlation( ) of all parameters with NAs removed, so effectively just for the third season (necromass would show up as NA before that):

This final scatter plot uses the function chart.Correlation( ) with data from only the parameters that we have data all three seasons for (so necromass has been removed):