8 Aleksandra Głowacka
THE INFLUENCE OF INTERCROPPING ON THE
AVAILABILITY AND UPTAKE OF NUTRIENTS BY PLANTS
Macroelements
Nitrogen
The rhizosphere is a complex environment where roots interact with the
physical, chemical and biological properties of soil, and which is influenced
by the presence and activity of the roots (Richardson et al., 2009, Zhang et al.,
2013 ). Numerous studies confirm the importance of the interaction between
plants and the changes in the rhizosphere in intercropping on the availability
and uptake of nutrients (Wasaki et al., 2003, Li et al., 2004 ). Intercropping of
legumes and cereals increases the availability and retrieval of nitrogen
(Karpenstein-Machan and Stuelpnagel 2000, Hauggaard-Nielsen et al., 2001 ).
The differences in the competitive abilities of component species my increase
nitrogen uptake by cereals - plants with higher competitive ability - and these
my conversely stimulate nodulation in legumes. On the other hand, an increase
in nitrogen acquisition may also be attributed to nitrogen transfer to cereals
from pulses. The legume uses fixed atmospheric N 2 rather than the soil
mineral N which can be exploited by the companion crop. Differences in the
date of sowing and harvesting can also affect the accumulation of nitrogen by
intercropped plants. Li et al., ( 2001 ) observed less uptake of nitrogen by maize
in wheat/maize strip intercropping compared to sole cropping, but only in the
earlier stages of development. In the later stages, after wheat harvest,
accumulation of nitrogen was faster, and as a result nitrogen content in the
strip-cropped maize in the full maturity stage was higher or similar to that in
sole cropping. However, this is not always the case, since Inal et al., ( 2007 )
did not observe a substantial increase in nitrogen content in legumes/non-
legumes intercropping (Figure 1).
Similarly, the results obtained by Głowacka (2014b) demonstrated that
narrow-leafed-lupin/dent-maize/oats strip-cropping significantly reduced the
content and uptake of nitrogen by maize. The lowest nitrogen content was
found in the edge row of the maize strip adjacent to the oats, but nitrogen
uptake was lowest in the inner row of the maize strip (Table 1). Oats, sown
three weeks earlier, developed rapidly during spring and early summer and
could compete with the maize for nitrogen. However, according to
Ghaffarzadeh et al., ( 1998 ), increased total nitrogen uptake by maize in the
border rows of the strip, both next to oat and soy, suggests that maize has an