Agriculture Reference
In-Depth Information
TABLE 5.8
Nitrogen Use Efficiency of 19 Upland Rice Genotypes
Agronomic
Efficiency
(mg mg
−
1
)
Physiological
Efficiency
(mg mg
−
1
)
Agrophysiological
Efficiency
(mg mg
−
1
)
Apparent
Recovery
Efficiency (%)
Utilization
Efficiency
(mg mg
−
1
)
Genotype
CRO 97505
23.5ab
100.2a
55.4a
43.5a
42.5ab
CNAs 8993
26.7a
101.4a
59.0a
47.8a
45.5ab
CNAs 8812
24.2ab
80.5a
41.3a
58.2a
47.0ab
CNAs 8938
21.8ab
87.8a
46.3a
48.7a
40.9ab
CNAs 8960
21.7ab
79.3a
46.1a
48.3a
37.3ab
CNAs 8989
24.8aab
72.3a
42.3a
59.3a
42.4ab
CNAs 8824
17.0ab
73.7a
36.7a
47.0a
33.5b
CNAs 8957
22.4ab
72.3a
46.3a
50.7a
35.2ab
CRO 97422
19.8ab
85.7a
47.1a
45.0a
36.6ab
CNAs 8817
17.9ab
72.7a
33.6a
53.2a
38.3ab
CNAs 8934
20.3ab
83.3a
40.5a
50.2a
41.8ab
CNAs 9852
22.9ab
81.7a
48.9a
47.7a
38.4ab
CNAs 8950
21.0ab
88.5a
49.9a
44.7a
37.6ab
CNA 8540
22.2ab
89.7a
45.2a
53.5a
44.1ab
CNA 8711
19.4ab
79.2a
40.0a
48.1a
38.0ab
CNA 8170
12.8b
92.8a
28.0a
45.4a
42.0ab
BRS Primavera
22.6ab
89.8a
51.2a
45.8a
39.9ab
BRS Canastra
21.7ab
125.7a
57.7a
40.6a
47.4ab
BRS Carisma
24.2ab
89.6a
42.8a
56.2a
50.5a
Average
21.4
86.6
45.2
49.2
41.0
F-test
Genotype
*
NS
NS
NS
**
CV (%)
17
23
26
24
12
Source:
From Fageria, N. K., O. P. Morais, and A. B. Santos. 2010.
J. Plant Nutr
. 33:1696-1711. With permission.
*,**, NS: Significant at the 5% and 1% probability level and nonsignificant, respectively. Means followed by the same letter
in the same column are not significantly different at the 5% probability level by Tukey's test.
5.2.6 n
utrIent
e
ffICIenCY
r
atIo
Nitrogen or nutrient use efficiency is also expressed in nutrient efficiency ratio (NER), which
was suggested by Gerlof and Gabelman (1983) to differentiate genotypes into efficient and
inefficient nutrient utilizers. The equation to calculate this efficiency ratio is as follows (Baligar
et al., 2001):
units of yield in kg
units of element in tissue
NER
(
kg kg
−
1
)
=
in kg
The above equation is used for expressing the results of field experimentation. If the experiment
is conducted under greenhouse conditions, the unit of result expression is mg mg
−1
.
The author studied the nitrogen efficiency ratio of cover crops under different pH levels (Table
5.10). Acidity and cover crop species interaction was significant for NUE, indicating variations in
cover crop species to acidity levels for N uptake and utilization. Hence, the results of NUE under
three acidity levels are presented (Table 5.10). The NUE varied from 27.43 mg dry matter pro-
duced with the accumulation of 1 mg of N in the shoot of Brazilian lucerne to 57 mg dry matter
produced per mg of N uptake in the shoot of Black mucuna bean at high acidity level. The average
