Agriculture Reference
In-Depth Information
900
850
800
750
700
Y = 688.9582 + 2.53552X - 0.00914X
2
R
2
= 0.6632
650
600
0
90
150
210
30
60
120
180
Nitrogen applied (kg N ha
-1
)
FIGURE 1.7
Relationship between N application and number of tillers in flooded rice grown on an Inceptisol
of central Brazil. (Adapted from Fageria, N. K. 1998. Annual report of the project “The study of liming
and fertilization for rice and common bean in cerrado region”. National Rice and Bean Research Center of
Embrapa, Goiania, Brazil. With permission.)
to N fertilization depending on crop growth stage (Table 1.4). Tillering increased with the advance-
ment of the crop growth and maximal values were achieved between 35 and 71 days after sowing,
depending on the N rate, and then decreased thereafter. Grain yield in cereals is highly dependent
upon the number of spikelet-bearing tillers produced by each plant (Power and Alessi, 1978; Nerson,
1980). The number of productive tillers depends on environmental conditions during tiller bud ini-
tiation and subsequent developmental stages. Numerous studies have shown that tiller appearance,
abortion, or both are affected by environmental conditions, especially nutrient deficiencies (Black
and Siddoway, 1977; Power and Alessi, 1978; Masle, 1985).
TABLE 1.4
Numbers of Tillers in Lowland Rice at Different N Rates during Crop Growth Cycle
Days after Sowing
N Rate
22 (IT)
35 (AT)
71 (IP)
97(B)
112 (F)
140 (PM)
kg ha
−
1
m
−
2
0
506
681
652
541
499
468
30
516
749
715
547
516
495
60
574
880
772
601
571
531
90
599
759
751
597
561
522
120
632
876
812
623
573
569
150
619
862
883
660
580
592
180
557
880
903
662
588
572
210
565
819
934
666
590
581
R
2
0.82*
0.66*
0.96*
0.95**
0.91*
0.92*
Source:
Adapted from Fageria, N. K. and V. C. Baligar. 2001.
Commun. Soil Sci. Plant Anal
. 32:1405-1429.
With permission.
Note:
Values are averages of 3 years field trial.
*,**Significant at the 5% and 1% probability levels, respectively.
