Agriculture Reference
In-Depth Information
The yield of grain (t·ha
-1
)
Number of ears (pcs·m
-2
)
1000 grains weight (g)
Cultivar
2008 2009
2010
mean
2008 2009 2010
mean
2008
2009 2010
mean
Kobra Plus
7.41 6.47
4.45
6.11
663
483
501
549
49.6
44.6 43.5
45.9
Bogatka
7.82 6.73
5.36
6.63
539
447
419
468
56.6
50.1 51.5
52.7
Rywalka
8.18 6.41
6.11
6.90
614
458
409
494
54.1
44.7 48.7
49.1
Legenda
7.73 6.81
5.65
6.73
607
457
432
499
50.7
42.2 49.3
47.4
Mean
7.78 6.60
5.39 6.59 606
461
440
502
52.9
45.4 48.3 48.8
HSD (α=0.05)
0.51 ns*
0.31
63
ns
36
1.2
0.9
1.3
* ns - non significant differences
Table 5.
The grain yield of winter wheat grain and the elements of yield in conventional system
According to Seufert et al. [21], crop yields in organic farming are from 5 to 34% lower than
those in conventional farming. Those differences depend on plant species, soil type, fertiliza‐
tion, agriculture level and economic development of the country. Tyburski and Rychcik's [22]
study showed that winter wheat yield can reach 4.27 t ha
-1
in an organic farm and 5.63 t ha
-1
in a conventional one. According to the authors correct crop management in some of organic
farms can result in crop yields to be almost as high as in conventional farms.
Weed infestation is one of the most strongly limiting factors to cereals yields in organic farming
system. Weed communities differed in years and between tested varieties. The lowest level of
weed infestation was observed in 2008 (19-46 g m
-2
), whereas the biggest dry matter of weeds
was noted in 2010 (170-345 g m
-2
) (Table 6), the latter being connected with sparse canopies
after winter (Table 4). Percentage loss of plants during the winter was the highest in Bogatka
and Tonacja and the lowest in Smuga (Table 4). The comparison of common wheat and spelt
wheat varieties showed the highest abundance of weeds in Tonacja, Kobra Plus and Bogatka
(Table 6). Dry matter of weeds was the largest in Bogatka and Kobra Plus canopies. The lowest
number of weeds at dough stage was recorded in Ostka Strzelecka and spelt Schwabenkon
and the lowest dry matter of weeds in Smuga. In canopies of all varieties a few dicotyledonous
species dominated:
Viola arvensis, Stellaria media, Papaver rhoeas, Polygonum convolvulus,
Chenopodium album
. Monocotyledonous species were represented mainly by
Apera spica-venti
.
Weed infestation of winter wheat cultivated in conventional system was low (3.0 plants m
-2
,
2.1 g m
-2
on average) and did not differ significantly between varieties and years due to the
intensive chemical weed control using herbicides (Table 1, 7). That level of weed abundance
did not affect yields of winter wheat.
Varieties of common wheat and spelt wheat differed for some morphological features and for
canopy structure. Among tested cultivars spelt Schwabenkorn was significantly the tallest (122
cm on average at dough stage) (Figure 1). Differences in height between spelt and common
wheat varieties increased with advancing plant age, which influenced the competitive ability
against weeds and was reflected in dry matter of weeds (Table 6). The lowest variety in the
