Table 4 Effect of treatment and study year on the cover and richness of species groups in the four years of the early sowing plots (GLM).

Delayed sowing

G + D

− 2.287

0.022

− 1.537

0.124

− 3.230

0.001

− 1.668

0.095

0.361

0.718

D

3.852

 < 0.001

3.279

0.001

− 1.538

0.124

− 1.094

0.274

Study year

G + D

 2

3.320

 < 0.001

− 0.067

0.947

− 6.622

 < 0.001

− 6.400

 < 0.001

− 0.394

0.694

 3

4.135

 < 0.001

− 0.890

0.373

− 11.880

 < 0.001

− 7.271

 < 0.001

− 1.340

0.180

 4

3.504

 < 0.001

− 0.820

0.412

− 9.981

 < 0.001

− 6.982

 < 0.001

0.138

0.890

D

 2

7.175

 < 0.001

1.791

0.073

− 2.605

0.009

− 3.222

0.001

 3

8.128

 < 0.001

0.768

0.443

− 4.282

 < 0.001

− 7.316

 < 0.001

 4

7.838

 < 0.001

0.453

0.651

− 3.785

 < 0.001

− 7.966

 < 0.001

Delayed sowing × study year

G + D

 2

0.348

0.728

0.100

0.921

0.259

0.800

0.216

0.829

0.112

0.911

 3

− 0.432

0.666

1.136

0.256

3.137

0.002

1.385

0.166

1.473

0.141

 4

3.106

0.002

1.674

0.094

2.541

0.011

1.825

0.068

− 0.628

0.530

D

 2

− 0.876

0.381

− 1.050

0.294

− 0.555

0.579

− 2.432

0.015

 3

− 2.379

0.017

− 0.384

0.701

0.616

0.538

0.807

0.420

 4

− 0.508

0.612

− 1.181

0.237

0.336

0.737

2.063

0.039