Agriculture Reference
In-Depth Information
TABLE 5.9
Nitrogen Use Efficiency by Dry Bean Genotypes
Genotype
AE (mg mg
−
1
)
PE (mg mg
−
1
)
APE (mg mg
−
1
)
ARE (%)
UE (mg mg
−
1
)
Pérola
5.9
22.0efg
13.3ab
47.5
10.1
BRS Valente
3.7
26.5cdefg
12.7ab
27.0
7.3
CNFM 6911
4.7
28.7bcdef
13.9ab
30.3
8.7
CNFR 7552
8.4
48.3a
21.9ab
38.7
18.7
BRS Radiante
9.0
33.9abcdef
18.1ab
53.6
17.9
Jalo Precoce
6.3
30.7bcdef
14.8ab
40.9
13.1
Diamante Negro
7.1
24.7defg
12.6ab
48.1
13.1
CNFP 7624
11.5
42.0ab
22.8ab
50.4
21.2
CNFR 7847
9.0
27.8bcdefg
16.4ab
43.3
12.4
CNFR 7866
6.1
13.0 g
10.2b
60.5
8.2
CNFR 7865
6.2
27.6bcdefg
12.5ab
47.6
12.4
CNFM 7875
11.2
36.0abcde
21.5ab
52.3
18.8
CNFM 7886
10.6
35.7abcde
19.3ab
54.7
19.5
CNFC 7813
10.7
35.0abcde
20.6ab
51.6
18.1
CNFC 7827
11.8
40.1abc
24.4a
49.0
19.5
CNFC 7806
8.1
26.9bcdefg
15.3ab
48.7
14.0
CNFP 7677
10.7
35.6abcde
21.2ab
50.5
18.0
CNFP`7775
10.7
39.9abcd
23.2ab
46.2
18.3
CNFP 7777
8.1
30.8bcdef
15.7ab
51.4
15.9
CNFP 7792
3.9
19.2fg
10.5ab
37.2
7.4
Average
8.2
31.2
17.0
46.5
14.6
F-test
**
**
**
NS
**
Source:
From Fageria, N. K., L. C. Melo, and J. P. Oliveira. 2013.
J. Plant Nutr
. 36:2179-2190. With permission.
Note:
AE = agronomic efficiency, PE = physiological efficiency, APE = agrophysiological efficiency, ARE = apparent
recovery efficiency, and UE = utilization efficiency.
**, NS: Significant at the 1% probability level and nonsignificant, respectively. Within the same column, means followed by
the same letter do not differ significantly at 5% probability level by Tukey's test.
value of NUE at high acidity was 36.88 mg shoot dry weight per mg of N uptake. At the medium
acidity level, NUE varied from 23.77 to 48.42 mg mg
−1
, with an average value of 34.36 mg mg
−1
.
Similarly, at the low acidity level, maximum NUE of 40.44 mg kg
−1
was of Mucuna bean ana and
a minimum NUE of 24.97 mg mg
−1
was of the white jack bean. The average NUE at low acidity
was 31.54 mg mg
−1
. The decrease in NUE at medium acidity level was about 7% as compared to the
high acidity level. Similarly, the decrease in NUE at the low acidity level was 17% as compared to
the high acidity level. The decrease in NUE with decreasing acidity level may be associated with
a decrease in the shoot dry weight of cover crop species (Fageria et al., 2008). The decrease in the
shoot dry weight with decreasing soil acidity was associated with tolerance of tropical cover crop
species to soil acidity (Fageria et al., 2008).
5.2.7 nue
versus
C
rop
Y
Ield
As mentioned earlier, NUE is defined in several ways in the literature. The question is how the
NUEs are related to crop yields. Nitrogen is the principal constituent of numerous organic com-
pounds such as amino acids, proteins, nucleic acids, and compounds of secondary plant metabolism
such as alkaloids (Mengel et al., 2001). The efficiency of N uptake and use relative to the produc-
tion of grain requires that the processes associated with absorption, translocation, assimilation, and
redistribution of N operate effectively (Moll et al., 1982). Among these processes, the uptake of N
