14 Aleksandra Głowacka
Zinc
According to Gunes et al., (2007) and Li et al., (2004) wheat/chickpea
intercropping enhanced Zn contents in plants. Similarly, Zuo and Zhang
(2009) reported that interspecific root interactions and rhizosphere effects
could be linked to improved zinc uptake in dicot plants by intercropping with
graminaceous species in pairings which included maize/peanut,
guava/sorghum or maize and chickpea/wheat. Interspecific root interactions
and rhizosphere changes were associated with the ferric reductase activity
from peanut roots and the release of phytosiderophores of maize roots,
contributing to the increased chemical availability of Zn by chelation, which
helps plants obtain those essential elements from the soil (Inal et al., 2007).
Similarly, Inal and Guns (2008) reported that enhanced production of
phytosiderophores by maize and barley might be responsible for the increases
in Zn concentrations of peanut in intercropping (Figure 4).
In other studies (Głowacka 2013c, 2014c), strip cropping maize with oats
and narrow-leafed lupin or with common bean and spring wheat significantly
increased the Zn content of the maize biomass in comparison with sole
cropping. This was due to significantly higher Zn content in the maize from
the edge rows, both adjacent to the oat and to the narrow-leafed lupin
(Table 3, 4).
Figure 3. Changes of iron concentration in peanut/maize and barley/maize
intercropping. Data is from Inal and Guns (2008).