12 Aleksandra Głowacka
Figure 2. Changes of phosphorus concentration in peanut/maize and barley/maize
intercropping. Data is from Inal and Guns ( 2008 ).
Micronutrients
Iron
The uptake of micronutrients from the rhizosphere is the first step for
accumulating micronutrients into the plant. The interaction between plants in
intercropping can affect the mobility and availability of nutrients in the
rhizosphere and their uptake by plants (Wasaki et al., 2003 ). Intercropping
dicot and monocot plants, which have different strategies for responding to
iron deficiency, may increase its accessibility for dicots, especially in alkaline
soils (Zuo and Zhang 2009). The reasons for improvement of iron nutrition to
dicots, which are sensitive to iron deficiency under stress conditions, with
intercropping graminaceous species, might be due to root interaction of the
two species and exudates from graminaceous species create a favorable
condition in rhizosphere to dicots (Zheng et al., 2003 ). A study by Zuo et al.,
( 2000 ) found that the interaction in the root zone between maize and peanut
grown in intercropping increased the availability of iron and reduced
symptoms of iron deficiency in the peanut plants. In strip cropping, the
distance between plants in adjacent strips is greater, which may reduce the
strength of the interaction between them. However, Głowacka (2014c) also
found significantly higher iron content in the maize biomass in strip cropping