Agriculture Reference
In-Depth Information
Y = 2.6367 + 0.0732X
R 2 = 0.7073**
20
15
10
5
50
100
150
200
250
300
N uptaken in grain (mg plant -1 )
FIGURE 3.29 Relationship between N uptake in grain and grain yield of lowland rice. (From Fageria, N. K.
2009. The Use of Nutrients in Crop Plants . Boca Raton, Florida: CRC Press. With permission.)
and variable N losses by different mechanisms such as leaching, volatilization, or denitrification
(Kyveryga et al., 2013).
Nitrogen uptake is positively related to the grain yield in crops and understanding the N uptake-
yield relationship and quantifying N requirements would be of great benefit for optimizing N fertil-
ization for annual crops (Yue et al., 2012b). Nitrogen uptake-yield relationship for winter wheat has
been reported in various studies (Ortiz-Monasterio et al., 1997; Pathak et al., 2003; Liu et al., 2006;
Lopez-Bellido et al., 2008; Barraclough et al., 2010; Gaju et al., 2011; Giuliani et al., 2011; Pask
et al., 2012; Yue et al., 2012b). A higher amount of N uptake or accumulation in the grain of crop
plants is important because crop yield is significantly and linearly associated with N accumulated
in the grain (Figure 3.29). Generally, N uptake in the grain has significant positive associations
with the grain yield (Fageria and Baligar, 2001, López-Bellido et al., 2003). Hence, improving N
uptake in grain may lead to improved grain yield. Higher N concentration in shoots is also desirable
because if the shoot has a higher N concentration during crop growth, it is translocated to the grain
during higher plant demands and the yield is improved. Figure 3.30 shows that N uptake in the shoot
is significantly associated with grain yield in a quadratic fashion.
The author studied N uptake in the shoots and grains of upland rice at two N levels (Table 3.8).
Nitrogen uptake in the shoot varied from 72.1 to 142.3 mg pot −1 at a low N level with an average
value of 98.9 mg pot −1 . At a higher N level, N uptake in the shoot varied from 352.2 to 635.1 mg
pot −1 with an average value of 511.2 mg pot −1 . The uptake of N in the grain varied from 298.1 to
513.5 mg pot −1 across two N levels. The uptake of N in the shoot and grain followed the dry matter
yield of these two plant parameters. The uptake of N in the shoot (r = 0.85*) as well as in the grain
(0.93*) was having highly significant associations with grain yield. This indicates that increasing N
Y = 7.9793 + 0.4688 ′X - 0.0057X 2 R 2 =0.4717**
20
15
10
5
20
40
60
80
100
N uptake in shoot (mg plant -1)
FIGURE 3.30 Relationship between N uptake in shoot and grain yield of lowland rice. (From Fageria, N. K.
2009. The Use of Nutrients in Crop Plants . Boca Raton, Florida: CRC Press. With permission.)
Search WWH ::




Custom Search