Diversifying crop rotations with temporary grasslands - Université de ...

North
T5 Med
Spr C+
T10 WB
T-
T8 Dac
Aut C-
T6 Dac
Spr C+
T7 Dac
Aut C+
T2 Med
Aut C-
T8 Dac
Aut C-
T9 WB
T+
A) 36 experimental plots
T5 Med
Spr C+
T11 WB
T+M
T10 WB
T-
T7 Dac
Aut C+
T6 Dac
Spr C+
T9 WB
T+
T11 WB
T+M
T8 Dac
Aut C-
T7 Dac
Aut C+
T4 Med
Aut C+
T5 Med
Spr C+
T4 Med
Aut C+
T4 Med
Aut C+
T6 Dac
Spr C+
T9 WB
T+
T11 WB
T+M
T2 Med
Aut C-
T10 WB
T-
T5 Med
Spr C+
T2 Med
Aut C-
T7 Dac
Aut C+
T9 WB
T+
T8 Dac
Aut C-
T11 WB
T+M
77
T6 Dac
Spr C+
T10 WB
T-
T4 Med
Aut C+
T2 Med
Aut C-
West South
East
BM
BM
BM
B) One plot
BM
Q1
Q2
Q3
a b c d e
6 micro-plots
Fig. 10: A) Spatial set up of the 36 experimental plots (9 crop treatments * 4 repetitions) on an experimental field
with 6*9=54 plots. B) Localisation of plant density and biomass measurements on the 6 micro-plots of each plot.
Each plot measures 7.5 m x 10 m = 75 m². Black lines are 4 m wide alleys around the plots. Grey plots were not
used. For practical reasons, both spring-sown crop treatments (T5 and T6) were grouped together (in the upper
line of the graph). Each plot is composed by 6 micro-plots (a-f, about 1.5 m wide). On five micro-plots (a-e),
weed seeds had been added to the soil (see section C.II.2.1.1), micro-plot f was the unsown control (striped).
Quadrats (Q1-Q3) show the location of the fixed zones where weed plant densities were regularly measured;
quadrats (BM) show the non-fixed zones, where the crop and weed biomasses were successively measured
(destructive in the annual crops, ‘quasi non-destructive’ in the perennial crops due to hay cuttings few days later
and regrowth); small red dots show the approximate location of the 8 soil cores taken for seed bank evaluation,
the black dot the soil cores taken for chemical analysis.
C.II.2.2.3
Chemical soil parameters
Soil samples were taken 7 weeks after the beginning of the experiment and after two years at
two soil layers (1: 0-30cm, 2: 30-60cm) using a ‘ Pürkhauer’
type soil core sampler (diameter
= 5 cm) on micro-plots d (see details in Fig. 10).
Chemical soil analyses of both sampling
dates were performed by an external service ‘Laboratoire Départemental de la Côte d’Or’
using standardized methods.
Results of the chemical soil analysis are summarized in Table 8. Both organic carbon and total
nitrogen concentrations decreased always with soil depth. While carbon concentrations did not
change from the first to the second sampling date, total nitrogen showed an increasing
tendency which led to narrower C/N ratios.
Q1
Q2
Q3
f