Agriculture Reference
In-Depth Information
TABLE 6.13
Influence of N on the Uptake of Zn in the Shoot
of 60-Day-Old Dry Bean Plants
N Rate (kg ha
−1
)
Zn Uptake (g ha
−1
)
0
14.0
40
27.7
80
38.4
120
42.1
160
62.0
200
88.5
R
2
0.79**
**Significant at the 1% probability level.
The trafficking of Zn from the rhizosphere into grains is dependent on various protein and other
nitrogenous compounds, including amino acids and peptides (Kutman et al., 2011). Kutman et al.
(2010) reported that grain protein is a sink of Zn. High N can increase the grain Zn concentration by
enhancing the grain protein concentration and thereby the sink strength of the grain for Zn. Significant
positive correlations between seed protein and Zn have been documented in various studies (Peleg
et al., 2008; Zhao et al., 2009). Although both the uptake and remobilization of Zn in wheat plants are
positively affected by N nutrition (Erenoglu et al., 2001), the share of concurrent uptake during grain
filling in grain Zn deposition is increased by higher N supply (Kutman et al., 2011, 2012).
Fageria and Baligar (2005) studied influence of N on the uptake of Zn in the shoot of dry bean
(Table 6.13). Nitrogen fertilization significantly increased Zn uptake in the plant tissue with the
increasing N levels in the range of 0 to 200 kg N ha
−1
. Nitrogen application was responsible for 79%
variation in the uptake of Zn. Hence, it can be concluded that N is one of the main factors in increasing
Zn uptake. These authors reported that increase in Zn uptake was related to increase in dry matter of
dry bean plants. Pederson et al. (2002) also reported that N concentration was highly correlated with
Zn concentration in aboveground plant parts of ryegrass. Nitrogen application has been reported to
influence Zn absorption by plants and vice versa (Aulakh and Malhi, 2005). In corn, the Zn concentra-
tion in shoots was higher when both N and Zn were applied together followed by the application of Zn
and N alone (Dev and Shukla, 1980).
6.3.2 n
ItroGen
versus
C
opper
Copper deficiency has been reported in many parts of the world in crop plants. According to
Sillanpaa (1990), 14% of the world soils are Cu deficient. Copper deficiency has been reported in
Brazilian Oxisols (Goedert, 1983; Hitsuda et al., 2010). Nearly 70-80% of Cerrado Oxisols are
deficient in Zn, Cu, or Mn (Lopes and Cox, 1977). Micronutrient deficiencies in crop plants are
widespread because of (i) increased micronutrient demands from intensive cropping practices and
adaptation of high-yielding cultivars, which may have higher micronutrient demand, (ii) enhanced
production of crops on marginal soils that contain low levels of essential nutrients, (iii) increased
use of high analysis fertilizers with low amounts of micronutrients, (iv) decreased use of animal
manures, composts, and crop residues, (v) use of many soils that are inherently low in micronutri-
ent reserves, (vi) involvement of natural and anthropogenic factors that limit adequate supplies and
create element imbalances (Fageria et al., 2002), and (vii) liming acid soils (Figure 6.10). Fageria
and Baligar (1997) reported that cereals and legumes grown on Oxisols responded significantly to
macro- and micronutrient fertilization.
