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

perennial crops with different management options (crop species, sowing date and cutting
frequency), and three treatments represented a succession of annual crops varying only by the
intercrop management (see Table 6 in Manuscript 3 for details). The natural soil seed bank of
the experimental field was supplemented by homogeneously adding seeds of 17 common
annual weed species (see Table 7 for species names) on all experimental plots. One sixth of
each plot stayed unsown for control (see methods in Manuscript 3 for details).
B.II.3 Data collection
The development of weed populations and community dynamics was investigated by
determining and counting the number of plants of all species every 4-7 weeks in spring,
summer and autumn on permanently installed quadrats in the sown and unsown zones.
Additionally, the aboveground biomass of crops and all weed species was measured 5-6 times
per year to assess the competitive relations between the species.
B.II.4 Statistical analysis
The temporal development of weed species composition in the nine crop treatments was
compared using Multiple Response Permutation Procedure (MRPP, McCune and Grace, 2002)
with pairwise tests at each measurement date. Indicator Species Analysis (ISA, Dufrene and
Legendre, 1997) was used to calculate and test ‘Indicator Values’ (IV) for the emerged weed
plants at the end of the experiment.
B.III GREENHOUSE EXPERIMENTS ANALYZING THE REGROWTH
CAPACITY OF WEED PLANTS AFTER CUTTING
B.III.1 Rationale
PFCs are harvested several times per year which is one of the most important differences to
most annual crops. Forage mowing creates frequent disturbances of the aboveground
vegetation, destroying the upper parts of the shoots of both the forage and the weed plants. In
PFCs, weed population and community dynamics may thus strongly depend on the plant’s
capacity to survive, grow and reproduce after such cutting operations. There are several other
situations, where weeds may be submitted to repeated physical disturbances of the
aboveground plant organs, including mowing in set-aside fields (Dalbies-Dulout and Dore,
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