Agriculture Reference
In-Depth Information
TABLE 1.24
Grain Harvest Index of Principal Field Crops
Crop Species
Grain Harvest Index
Corn
0.62
Upland rice
0.51
Lowland rice
0.47
Wheat
0.56
Barley
0.57
Sorghum
0.70
Oat
0.48
Triticale
0.46
Soybean
0.35
Chickpea
0.55
Faba bean
0.62
Field pea
0.58
Lentil
0.51
Mungbean
0.55
Peanut
0.57
Dry bean
0.52
Sunflower
0.48
Canola
0.41
Lupin
0.50
Vetch
0.47
Source:
Adapted from Fageria, N. K. and A. B. Santos. 2008.
J. Plant Nutr
.
31:983-1004; Fageria, N. K., A. B. Santos, and V. A. Cutrim. 2007.
Pesq. Agropec. Bras
. 42:1029-1034; Unkovich, M., J. Baldock, and
M. Forbes. 2010.
Adv. Agron
. 105:173-219. With permission.
in the GHI was 44% with the addition of 400 mg N kg
−1
as compared to control treatment. These
results indicate that higher GHI values can be obtained with proper N management in annual crops.
The GHI of important field crops is presented in Table 1.24.
Improvement in GHI of corn genotypes with the addition of N has been reported by Costa et al.
(2002a). These authors reported that GHI of corn hybrids varied from 0.47 to 0.53 at one location
and from 0.52 to 0.62 at another location. Begna et al. (1997) reported GHI values of corn hybrids
within this range. A higher variation in GHI among corn genotypes was observed at low N rates
(0 and 85 kg N ha
−1
) than at the intermediate or the higher N rates (170 and 255 kg N ha
−1
). Roth
et al. (2013) reported increase in the GHI of five corn hybrids with the addition of N in the range of
0-269 kg ha
−1
.
1.2.7 r
ole
of
n
ItroGen
In
I
nCreasInG
Y
Ield
p
otentIal
of
I
mportant
C
ereals
In
the
f
uture
Before discussing the role of N in increasing the yield potential of important cereals in the future,
it is logical to define yield and yield potential. There are several definitions of yield potential in the
literature. For example, potential yield is an estimate of the upper limit of yield increase that can be
obtained from a crop plant (Fageria, 1992). Reynolds et al. (1999) defined genetic yield potential as
the yield of adapted lines in a favorable environment in the absence of agronomic constraints. Evans
and Fischer (1999) defined potential yield as the maximum yield that could be reached by a crop or
