Agriculture Reference
In-Depth Information
TABLE 3.13
Nitrogen Harvest Index of Upland Rice Genotypes at Two
N Levels
Nitrogen Harvest Index
Genotype
0 mg N kg
−
1
400 mg N kg
−
1
CRO 97505
0.82a
0.73ab
CNAs 8993
0.44a
0.53b
CNAs 8812
0.80a
0.79ab
CNAs 8938
0.57a
0.68ab
CNAs 8960
0.67a
0.69ab
CNAs 8989
0.67a
0.75ab
CNAs 8824
0.65a
0.71ab
CNAs 8957
0.43a
0.78ab
CRO 97422
0.80a
0.85a
CNAs 8817
0.47a
0.74ab
CNAs 8934
0.71a
0.69ab
CNAs 9852
0.45a
0.85a
CNAs 8950
0.44a
0.78ab
CNA 8540
0.47a
0.85a
CNA 8711
0.71a
0.85a
CNA 8170
0.69a
0.78ab
BRS Primavera
0.71a
0.85a
BRS Canastra
0.70a
0.85a
BRS Carisma
0.79a
0.88ab
Average
0.62b
0.77a
F-test
N level (N)
**
Genotype (G)
**
N × G
**
**Significant at the 1% probability level. Within the same column, means followed by the
same letter do not differ significantly at the 5% probability level by Tukey's test. Average
values were compared in the same line.
magnitude of nutrient deficiency (Fageria and Baligar, 2005a). Crop response to the applied nutrient
can be evaluated under both greenhouse and field conditions. Greenhouse or controlled condition
experiments are those of short duration conducted to develop and understand the basic principles of
soil fertility and plant nutrition. On the other hand, field experiments are of relatively longer dura-
tion and are conducted to understand the applied part of crop production. Field experiments are
more costly compared to greenhouse experiments.
In the author's opinion, controlled condition experimental results cannot be extrapolated to
field conditions due to the large variation in environmental factors under field conditions. In gen-
eral, however, properly conducted greenhouse and laboratory studies often give useful evidence
as to the factors that merit investigation under field conditions. For example, if greenhouse experi-
ments indicate rather marked differences in response among the fertilizers, the consideration of
field experiments is justified. Pot experiments are also valuable in relating the observed laboratory
measurement to actual plant response and they are important in establishing the basic principles
of soil-fertilizer-plant relationships. Both types of experimentation are important and should be
complementary in solving the problem of crop production in general. Hence, these two techniques
