Agriculture Reference
In-Depth Information
30
25
20
15
10
5
0
Upland rice genotypes
FIGURE 5.2
Agronomic efficiency of upland rice genotypes. (From Fageria, N. K. 2014.
Mineral Nutrition
of Rice
. Boca Raton, Florida: CRC Press. With permission.)
5.2.2 p
hYsIoloGICal
e
ffICIenCY
PE is defined as the biological yield (grain plus straw) obtained per unit of N uptake by both grain
and straw. It can be calculated by using the following equation:
BY in kg
−
−
BY
in kg
f
uf
PE kg kg
(
−
1
)
=
N n kg
N n kg
uf
uuf
where BY
f
is the biological yield (grain plus straw) of the fertilized plot, BYf
uf
is the biological yield
of the unfertilized plot, N
uf
is the N uptake of the fertilized plot (grain plus straw), and N
uuf
is the N
uptake of the unfertilized plot (grain plus straw).
Fageria and Baligar (2001) calculated the PE of lowland rice under different N rates (Table 5.3). It
varied from 113 to 182 kg kg
−1
, with an average value of 146 kg kg
−1
. There was a highly significant
variation in PE when N was applied in the range of 30-210 kg ha
−1
. The variation in PE was 62%
with the addition of N in the range of 30-210 kg ha
−1
. Fageria et al. (2007) reported that PE varied
from 105 to 222 kg kg
−1
, with an average value of 155 kg kg
−1
.
5.2.3 a
GrophYsIoloGICal
e
ffICIenCY
APE is defined as the economic production (grain yield in case of annual crops) per unit of N uptake
in grain plus straw. APE can be calculated by using the following equation:
GY in kg
−
−
GY in kg
f
uf
APE kg kg
(
−
1
)
=
N n kg
N n kg
uf
uuf
