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four groups, 50 % of plants were clipped. CP and NC plants were alternately planted within
each pot.
When th e f irst s iliques w ere m atured completely (i.e. yellow in c olor), th e s iliques
were counted on every plant, then all the plants were cut at the base and left to dry at room
temperature, an d t hey were t hreshed t o co llect t he s eeds. S tems an d l eaves an d s ilique
material, e xcept s eeds, were dr ied i n a n ove n a t 80 °C f or 48 h, a nd f inal dr y w eight w as
measured. Seed number per plant was calculated. The averaged CP and NC data per plot were
used in fixed-effects ANOVA, and we used a 0.05 probability level for statistical significance.
RESULTS
Effects of different percentages of NC plants
The ANOVA showed that clipping leaves had a significant effect on the three measures. NC
plants pr oduced m ore s iliques, hi gher bi omass and m ore s eeds ( Table 3.1) t han C P. N o
difference was obs erved a mong t reatments for t he N C pe rcentage, and t here w as no
interaction (Table 3.1).
Among the different NC percentages, no difference was recorded for the three measures of
NC: s ilique num ber ( df=3, F =1.32, P =0.30), bi omass ( F=1.20, P =0.35), a nd s eed num ber
(F=0.68, P=0.58). For CP, different treatments showed different silique number (df=3, F=5.58,
P=0.012) and biomass (F=7.88, P= 0.0036), but not different seed number (F=1.93, P= 0.18).
CP plants in pure stands produced two times more than in 50% mixed stands.
When l ooking a t t he given N C pe rcentage t reatments, s ome s ignificant di fferences
appeared between NC and CP in spite of high variability. At the mixed stand of 75% NC, NC
population pr oduced m ore s iliques ( df=1, F =8.11, P =0.029) a nd hi gher biomass ( F=21.97,
P=0.003) than CP on average. At the 50% mixed stand, the differences reached a maximum:
the average silique number (80±7) was 2.9-fold more than CP (27±4) (F=8.11, P=0.029); the
biomass of NC (10.84±0.36) was 3.2-fold more than CP (3.29±0.19) (F=21.97, P=0.003); and
seed number (460±43) of NC was 3.3-fold more than CP (138±16) (F=11.92, P=0.014). There
was no difference at the 25 % NC treatment.
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