Agriculture Reference
In-Depth Information
allelopathic and competitive abilities [28]. Those authors indicates that both the allelopathic
potential and the competitiveness connected with morphological characteristics of variety are
quantitative factors of complex inheritance which are also dependent on environmental
conditions.
The relationship between weed infestation and grain yield of winter wheat varieties was
analyzed (Figure 3-5). In 2008 the dry matter of weeds was low, less than 50 g m
-2
and it probably
had no significant effect on grain yield of wheat cultivars. Due to favorable weather condi‐
tions of that year grain yields were high, from 3.8 t ha
-1
of hulled grain of spelt to 6.2 t ha
-1
in
Bogatka and Kobra Plus. At low weed pressure, Kobra Plus and Bogatka gave the highest yield,
but when the weed infestation was high, 180 g m
-2
and more, as in 2009 and 2010, the grain yield
was low (Figure 4-5). At the weed infestation of 100-110 g m
-2
spelt Schwabenkorn and Smuga
gave high yields, about 4 t ha
-1
(Figure 4). In 2010, due to poor winter survival of varieties and
unsuitable weather conditions, the yields of all varieties were low (Figure 5). Analysis showed
that with the increase in dry weight of weeds grain yields decreased. The highest grain yields
and the lowest infestation was found in Smuga, whereas Ostka Strzelecka and Tonacja were
the lowest yielding variety with the highest weed weight (280-290 g m
-2
) (Figure 5).
7
6
Kobra Plus
5
Bogatka
4
Smuga
Tonacja
3
Ostka Strzelecka
2
spelt
1
0
0
50
100
150
200
250
300
350
weed dry matter (g·m
2
)
Figure 3.
The dependence between weed dry matter and grain yield of winter wheat varieties cultivated in organic
system at dough stage in 2008
The infection by pathogens can be as well as weed infestation the yield limiting factors in
organic farming [6]. The similar effect can be produced by restricted nitrogen supply of plants
[12]. The results showed that stem base disease incidence was relatively low in winter wheat
varieties (approximately 10%) (Table 9). Comparison of sanitary conditions of winter wheat
growth under conventional vs. organic system indicate that crop rotation applied in organic
