Abstract:
Mixed intercropping of barley and wheat has been reported as the
practice of smallholder farmers in some dryland areas of Ethiopia. However,
this cropping system has not yet received the attention of research.
Therefore, this study was conducted to determine the level of competition and
yield advantage in barley and wheat mixed intercropping under different
stress levels of moisture deficit.
One pot and one field experiments were conducted to address these
objectives. In the pot experiment, three irrigation water levels (75-80, 50-55,
and 25-30% depletion of soil available water), five intercropping ratios (%)
of barley to wheat in a replacement series (100/0, 75/25, 50/50, 25/75, and
0/100), and four planting densities (4, 8, 12 and 16 plants/pot) were studied
in a split-split plot design and had three sets so as to harvest at tillering,
heading and maturity stages. In the field, the five intercropping ratios and the
four water levels supplied by sprinkler irrigation system were studied in a
split-plot design. Intra- and inter-specific competition decreased with
decreasing stress levels of moisture deficit; but increased with increasing
planting densities in all harvesting stages in the pot experiment. However,
both competition types were higher at tillering stage but progressively
decreased in later harvesting stages. Intraspecific competition was more
important for barley at early stages and for wheat at later stages of the
growing period. Both pot and field experiments proved that barley was less
competitive than wheat towards the reproductive stage. Yield advantage of
mixed intercropping of barley and wheat increased with increasing stress
levels of moisture deficit under study. Yield advantage and productivity
tended to be dominated by the higher yielding crop species in the mixture.
This result suggests mixed intercropping of barley and wheat is not a priority
in areas where moisture is not limiting in amount and distribution. It is
advisable to use 50%barley + 50%wheat ratio since it is difficult to predict
which crop performs better than the other in such unpredictable rainfall
conditions of the drylands
