Treatments

Main crop and green manure

Treatment Year2019 Year2020&2021 Year2022
Main Spring wheat Spring Barley Potato
Mixture annual mixture Peronnial mixture (until end of 2021) -
Fibrous root sudan grass Tall fescue & english ryegrass (until end of 2021) -
Taproot fodder radish Lucerne (until end of 2021) -

Mechanical treatment

Mechanical treatment
SS Subsoiling
SB Small boreholes
LB Large boreholes
Ref Untreated

The experimental design

The field is divided into four blocks. Every block is divided into three subplots. Every treatment occurs once in each subplot. We make the assumption that the treatments are divided randomly in each subplot.

The data

Boxplots of penetration resistance per cm

Boxplots of penetration resistance per 10cm

The penetration resistance is larger in 2022 compared to the zero measurements for depths between 11 and 70 cm.

Results per 5 cm

Depth 0-5 cm

Plots

There are no missing values.

Results

There is no significant effect of the different cover crop treatment groups on the penetration resistance.

## Anova Table (Type III tests)
## 
## Response: druk
##              Sum Sq  Df F value    Pr(>F)    
## (Intercept)  5.8144   1 90.4513 < 2.2e-16 ***
## treatment    0.0211   2  0.1642 0.8486799    
## blok         0.6700   3  3.4743 0.0170354 *  
## blok:baan    2.0578   8  4.0015 0.0001989 ***
## Residuals   12.9850 202                      
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots  0.543 0.0299 202    0.484    0.602
##  Mixture        0.540 0.0299 202    0.481    0.599
##  Taproots       0.521 0.0299 202    0.462    0.580
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture   0.00278 0.0423 202   0.066  0.9976
##  Fibrous roots - Taproots  0.02222 0.0423 202   0.526  0.8588
##  Mixture - Taproots        0.01944 0.0423 202   0.460  0.8899
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 6-10 cm

Plots

There are no missing values.

Results

There is no significant effect of the different cover crop treatment groups on the penetration resistance.

## Anova Table (Type III tests)
## 
## Response: druk
##              Sum Sq  Df  F value    Pr(>F)    
## (Intercept) 25.5210   1 353.0636 < 2.2e-16 ***
## treatment    0.1768   2   1.2228   0.29704    
## blok         2.3058   3  10.6331  1.97e-06 ***
## blok:baan    1.3511   8   2.3364   0.02102 *  
## Residuals   11.9992 166                       
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots  1.070 0.0347 166    1.001     1.14
##  Mixture        0.995 0.0347 166    0.926     1.06
##  Taproots       1.018 0.0347 166    0.950     1.09
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture    0.0750 0.0491 166   1.528  0.2805
##  Fibrous roots - Taproots   0.0517 0.0491 166   1.053  0.5449
##  Mixture - Taproots        -0.0233 0.0491 166  -0.475  0.8830
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 11-15 cm

Plots

There are no missing values.

Results

There is strong evidence of an effect of cover crop treatment on penetration resistance. Treatment of fibrous roots results in significant higher resistance compared to mixture and taproots.

## Anova Table (Type III tests)
## 
## Response: druk
##             Sum Sq  Df  F value    Pr(>F)    
## (Intercept) 40.915   1 713.7880 < 2.2e-16 ***
## treatment    2.454   2  21.4069 5.358e-09 ***
## blok         1.130   3   6.5703 0.0003182 ***
## blok:baan    0.946   8   2.0625 0.0422230 *  
## Residuals    9.515 166                       
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   1.54 0.0309 166     1.48     1.60
##  Mixture         1.27 0.0309 166     1.21     1.34
##  Taproots        1.31 0.0309 166     1.25     1.37
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture     0.263 0.0437 166   6.024  <.0001
##  Fibrous roots - Taproots    0.228 0.0437 166   5.224  <.0001
##  Mixture - Taproots         -0.035 0.0437 166  -0.801  0.7031
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 16-20 cm

Plots

There are no missing values.

Results

There is strong evidence of an effect of cover crop treatment on penetration resistance. Treatment of fibrous roots results in significant higher resistance compared to mixture and taproots.

## Anova Table (Type III tests)
## 
## Response: druk
##             Sum Sq  Df  F value    Pr(>F)    
## (Intercept) 56.370   1 893.2416 < 2.2e-16 ***
## treatment    2.041   2  16.1743 3.823e-07 ***
## blok         2.324   3  12.2753 2.707e-07 ***
## blok:baan    2.272   8   4.5011 5.748e-05 ***
## Residuals   10.476 166                       
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   1.79 0.0324 166     1.73     1.86
##  Mixture         1.54 0.0324 166     1.48     1.61
##  Taproots        1.60 0.0324 166     1.54     1.66
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture     0.248 0.0459 166   5.414  <.0001
##  Fibrous roots - Taproots    0.193 0.0459 166   4.215  0.0001
##  Mixture - Taproots         -0.055 0.0459 166  -1.199  0.4553
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 21-25 cm

Plots

There are no missing values.

Results

There is strong evidence of an effect of cover crop treatment on penetration resistance. Treatment of fibrous roots results in significant higher resistance compared to mixture and taproots.

## Anova Table (Type III tests)
## 
## Response: druk
##             Sum Sq  Df   F value    Pr(>F)    
## (Intercept) 63.937   1 1142.5566 < 2.2e-16 ***
## treatment    1.577   2   14.0934 2.222e-06 ***
## blok         0.546   3    3.2523   0.02323 *  
## blok:baan    1.939   8    4.3305 9.233e-05 ***
## Residuals    9.289 166                        
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   2.06 0.0305 166     2.00     2.12
##  Mixture         1.91 0.0305 166     1.85     1.97
##  Taproots        1.83 0.0305 166     1.77     1.89
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture    0.1433 0.0432 166   3.319  0.0032
##  Fibrous roots - Taproots   0.2267 0.0432 166   5.248  <.0001
##  Mixture - Taproots         0.0833 0.0432 166   1.929  0.1336
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 26-30 cm

Plots

There are no missing values.

Results

There is strong evidence of an effect of cover crop treatment on penetration resistance. Treatment of fibrous roots results in significant higher resistance compared to mixture and taproots.

## Anova Table (Type III tests)
## 
## Response: druk
##             Sum Sq  Df  F value    Pr(>F)    
## (Intercept) 73.852   1 972.9394 < 2.2e-16 ***
## treatment    2.857   2  18.8194 4.301e-08 ***
## blok         1.142   3   5.0143   0.00236 ** 
## blok:baan    3.363   8   5.5376 3.260e-06 ***
## Residuals   12.600 166                       
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   2.39 0.0356 166     2.32     2.46
##  Mixture         2.14 0.0356 166     2.07     2.22
##  Taproots        2.10 0.0356 166     2.03     2.18
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture     0.245 0.0503 166   4.871  <.0001
##  Fibrous roots - Taproots    0.285 0.0503 166   5.666  <.0001
##  Mixture - Taproots          0.040 0.0503 166   0.795  0.7065
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 31-35 cm

Plots

There are no missing values.

Results

There is strong evidence of an effect of cover crop treatment on penetration resistance. Treatment of fibrous roots results in significant higher resistance compared to mixture and taproots.

## Anova Table (Type III tests)
## 
## Response: druk
##             Sum Sq  Df  F value    Pr(>F)    
## (Intercept) 91.238   1 881.7565 < 2.2e-16 ***
## treatment    2.231   2  10.7827 3.956e-05 ***
## blok         1.684   3   5.4265 0.0013849 ** 
## blok:baan    2.959   8   3.5742 0.0007505 ***
## Residuals   17.177 166                       
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   2.50 0.0415 166     2.42     2.59
##  Mixture         2.28 0.0415 166     2.19     2.36
##  Taproots        2.26 0.0415 166     2.18     2.34
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture     0.228 0.0587 166   3.888  0.0004
##  Fibrous roots - Taproots    0.243 0.0587 166   4.143  0.0002
##  Mixture - Taproots          0.015 0.0587 166   0.255  0.9647
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 36-40 cm

Plots

There are no missing values.

Results

There is strong evidence of an effect of cover crop treatment on penetration resistance. Treatment of fibrous roots results in significant higher resistance compared to mixture and taproots.

## Anova Table (Type III tests)
## 
## Response: druk
##             Sum Sq  Df   F value    Pr(>F)    
## (Intercept) 98.454   1 1210.8066 < 2.2e-16 ***
## treatment    1.162   2    7.1459 0.0010543 ** 
## blok         1.054   3    4.3201 0.0058079 ** 
## blok:baan    2.654   8    4.0796 0.0001853 ***
## Residuals   13.498 166                        
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   2.51 0.0368 166     2.44     2.58
##  Mixture         2.40 0.0368 166     2.33     2.48
##  Taproots        2.31 0.0368 166     2.24     2.39
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture    0.1050 0.0521 166   2.017  0.1113
##  Fibrous roots - Taproots   0.1967 0.0521 166   3.778  0.0006
##  Mixture - Taproots         0.0917 0.0521 166   1.761  0.1861
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 41-45 cm

Plots

There are no missing values.

Results

There is no significant effect of the different cover crop treatment groups on the penetration resistance.

## Anova Table (Type III tests)
## 
## Response: druk
##              Sum Sq  Df   F value  Pr(>F)    
## (Intercept) 106.642   1 1048.9198 < 2e-16 ***
## treatment     0.603   2    2.9655 0.05427 .  
## blok          0.799   3    2.6202 0.05256 .  
## blok:baan     2.164   8    2.6606 0.00898 ** 
## Residuals    16.877 166                      
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   2.63 0.0412 166     2.55     2.71
##  Mixture         2.50 0.0412 166     2.42     2.58
##  Taproots        2.53 0.0412 166     2.45     2.61
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture     0.135 0.0582 166   2.319  0.0559
##  Fibrous roots - Taproots    0.105 0.0582 166   1.804  0.1715
##  Mixture - Taproots         -0.030 0.0582 166  -0.515  0.8640
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 46-50 cm

Plots

There are no missing values.

Results

There is no significant effect of the different cover crop treatment groups on the penetration resistance.

## Anova Table (Type III tests)
## 
## Response: druk
##              Sum Sq  Df   F value    Pr(>F)    
## (Intercept) 140.250   1 1495.6113 < 2.2e-16 ***
## treatment     0.239   2    1.2731    0.2827    
## blok          4.115   3   14.6285 1.691e-08 ***
## blok:baan     4.661   8    6.2135 5.111e-07 ***
## Residuals    15.567 166                        
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   2.79 0.0395 166     2.71     2.86
##  Mixture         2.73 0.0395 166     2.65     2.80
##  Taproots        2.70 0.0395 166     2.62     2.78
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture    0.0617 0.0559 166   1.103  0.5136
##  Fibrous roots - Taproots   0.0867 0.0559 166   1.550  0.2704
##  Mixture - Taproots         0.0250 0.0559 166   0.447  0.8957
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 51-55 cm

Plots

There are no missing values.

Results

There is evidence of an effect of cover crop treatment on penetration resistance. Treatment A results in significant higher resistance compared to C.

## Anova Table (Type III tests)
## 
## Response: druk
##              Sum Sq  Df   F value    Pr(>F)    
## (Intercept) 149.017   1 1147.8006 < 2.2e-16 ***
## treatment     1.016   2    3.9146  0.021817 *  
## blok          4.035   3   10.3590 2.756e-06 ***
## blok:baan     3.566   8    3.4332  0.001107 ** 
## Residuals    21.552 166                        
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   2.94 0.0465 166     2.84     3.03
##  Mixture         3.06 0.0465 166     2.97     3.15
##  Taproots        2.88 0.0465 166     2.79     2.97
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture   -0.1233 0.0658 166  -1.875  0.1492
##  Fibrous roots - Taproots   0.0567 0.0658 166   0.861  0.6653
##  Mixture - Taproots         0.1800 0.0658 166   2.736  0.0188
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Depth 56-60cm

Plots

There are no missing values.

Results

There is strong evidence of an effect of cover crop treatment on penetration resistance. Treatment of mixture results in significant higher resistance compared to fibrous or taproots.

## Anova Table (Type III tests)
## 
## Response: druk
##              Sum Sq  Df   F value    Pr(>F)    
## (Intercept) 198.409   1 1107.5474 < 2.2e-16 ***
## treatment     3.409   2    9.5148 0.0001225 ***
## blok          7.763   3   14.4454 2.091e-08 ***
## blok:baan     4.995   8    3.4851 0.0009592 ***
## Residuals    29.738 166                        
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

##  treatment     emmean     SE  df lower.CL upper.CL
##  Fibrous roots   3.31 0.0546 166     3.20     3.42
##  Mixture         3.55 0.0546 166     3.44     3.66
##  Taproots        3.23 0.0546 166     3.12     3.33
## 
## Results are averaged over the levels of: baan, blok 
## Confidence level used: 0.95 
##  contrast                 estimate     SE  df t.ratio p.value
##  Fibrous roots - Mixture    -0.240 0.0773 166  -3.106  0.0063
##  Fibrous roots - Taproots    0.085 0.0773 166   1.100  0.5154
##  Mixture - Taproots          0.325 0.0773 166   4.206  0.0001
## 
## Results are averaged over the levels of: baan, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates