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 roots sudan grass Tall fescue & english ryegrass (until end of 2021) -
Taproots 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 mechanical treatments are divided over the blocks. The mechanical treatment will not be analysed, since we can not know if the variety between the mechanical treatments is explained by the treatment or by differences between the fields.

Moisture percentage depth 0-15

There are no significant effects between the different green manure treatments on fresh weight in 2022.

## Analysis of Variance Table
## 
## Response: bulkdensity2022[, var]
##              Df  Sum Sq Mean Sq F value  Pr(>F)  
## treatment     2  0.3758 0.18792  0.3593 0.70216  
## blok          3  4.3605 1.45350  2.7794 0.06511 .
## blok:subplot  8  6.3367 0.79209  1.5146 0.20877  
## Residuals    22 11.5050 0.52296                  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##  Shapiro-Wilk normality test
## 
## data:  model$residuals
## W = 0.97705, p-value = 0.6451
## 
## $emmeans
##  contrast                 estimate    SE df t.ratio p.value
##  Fibrous roots - Mixture     0.250 0.295 22   0.848  0.6780
##  Fibrous roots - Taproots    0.124 0.295 22   0.422  0.9071
##  Mixture - Taproots         -0.126 0.295 22  -0.426  0.9052
## 
## Results are averaged over the levels of: subplot, blok 
## Note: contrasts are still on the [ scale 
## P value adjustment: tukey method for comparing a family of 3 estimates 
## 
## $contrasts
##  contrast                                               estimate    SE df
##  (Fibrous roots - Mixture) - (Fibrous roots - Taproots)    0.126 0.295 22
##  (Fibrous roots - Mixture) - (Mixture - Taproots)          0.376 0.511 22
##  (Fibrous roots - Taproots) - (Mixture - Taproots)         0.250 0.295 22
##  t.ratio p.value
##    0.426  0.9052
##    0.736  0.7453
##    0.848  0.6780
## 
## Results are averaged over the levels of: subplot, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates

Moisture percentage depth 15-30

There are no significant effects between the different green manure treatments on fresh weight in 2022.

## Analysis of Variance Table
## 
## Response: bulkdensity2022[, var]
##              Df Sum Sq Mean Sq F value Pr(>F)
## treatment     2  4.247  2.1237  0.6033 0.5558
## blok          3  1.667  0.5557  0.1579 0.9235
## blok:subplot  8 20.194  2.5243  0.7171 0.6746
## Residuals    22 77.447  3.5203               
## 
##  Shapiro-Wilk normality test
## 
## data:  model$residuals
## W = 0.97904, p-value = 0.7131
## 
## $emmeans
##  contrast                 estimate    SE df t.ratio p.value
##  Fibrous roots - Mixture    -0.240 0.766 22  -0.313  0.9476
##  Fibrous roots - Taproots    0.579 0.766 22   0.755  0.7336
##  Mixture - Taproots          0.818 0.766 22   1.068  0.5431
## 
## Results are averaged over the levels of: subplot, blok 
## Note: contrasts are still on the [ scale 
## P value adjustment: tukey method for comparing a family of 3 estimates 
## 
## $contrasts
##  contrast                                               estimate    SE df
##  (Fibrous roots - Mixture) - (Fibrous roots - Taproots)   -0.818 0.766 22
##  (Fibrous roots - Mixture) - (Mixture - Taproots)         -1.058 1.327 22
##  (Fibrous roots - Taproots) - (Mixture - Taproots)        -0.240 0.766 22
##  t.ratio p.value
##   -1.068  0.5431
##   -0.797  0.7084
##   -0.313  0.9476
## 
## Results are averaged over the levels of: subplot, blok 
## P value adjustment: tukey method for comparing a family of 3 estimates