Treatments
Main crop and green manure
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
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

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


