Agriculture Reference
In-Depth Information
organic farming system due to its resistant to fungal leaf and stem diseases. Unfortunately,
yields of cv. Tybalt were highly variable over the study years. It can also be assumed (although
this was not investigated), that in the 3-year research period, availability of nitrogen and its
uptake, besides weeds and disease infestation, had a strong influence on the yields of spring
wheat varieties [12].
3.2.1. Summary
1.
Among the nine compared varieties, cvs. Tybalt and Żura produced the highest yields,
while cvs. Bryza and Nawra yielded the lowest.
2.
Crop yields were on average 34% lower in the organic system than in the conventional
one. The differences were from 32% (cvs. Tybalt and Vinjett) to 38% (cv. Parabola). Lower
yields in organic farming system were caused by lower ear density and thousand grain
weight (both showing a reduction of approximately 16%).
3.
The weed infestation of spring wheat was strongly limited by undersown crops (clover-
grass mixture). The dry matter of weeds averaged 36 g m
-2
over the research years (from
7 to 57 g m
-2
). The lowest dry matter of weeds was observed in Bombona, Raweta, Nawra
and Vinjett which had a bigger density of canopy.
4.
In the 3-year period a minor incidence of stem base and leaf diseases was observed due
to an appropriate crop rotation (stem base diseases) and favourable weather conditions
in June and July (fungal leaf diseases). Cv. Parabola was more susceptible, while cv. Tybalt
was more resistant to those diseases than the other varieties.
4. Conclusions
The yielding of cereals in organic system was lower than in conventional system. In case of
winter wheat, the yield was on average 45% smaller in organic system than in conventional
one. This low yield of winter wheat in organic system in years of research was mostly connected
with unfavorable weather conditions in growing season 2009/2010. Winter wheat cultivars
selected for organic farming should be characterized by high winter hardiness, because in this
farming system is difficult to compensate for the effects of adverse weather conditions. Cereal
canopy with a smaller plant density after winter is more susceptible to weed infestation. Earlier
studies conducted on another set of winter wheat varieties (Roma, Kobra, Zyta, Sukces)
showed a difference in the yields between organic and conventional systems by 19%. The
difference in cereal yields in organic vs. conventional systems are due to lower density of ears,
weed infestation, leaves diseases and nutrients deficiency [6, 9, 11, 12, 14, 20].
Tested varieties were differed in their yielding and competitiveness against weeds as well as
resistance to fungal diseases. Smuga variety gave the highest yield whereas Ostka Strzelecka
and spelt Schwabenkorn the lowest one. In case of spring wheat, 34% less grain yield on
average was obtained in organic system than in conventional one. Among compared varieties
