N management approaches

Total amount of N added (kg∙ha−1)

Amount of N saved (−)/extra added (+) compared to control (kg∙ha−1)

Rice grain yield

(t ha-1)

%Yield increased (+)/decreased (−) over control

Partial factor productivity for N (kg∙grain∙kg-1∙N)

BRRI dhan29

Dhani gold

BRRI dhan29

Dhani gold

BRRI dhan29

Dhani gold

BRRI recommended N (control)

138

0

6.49

6.05

0

0

47.0

43.8

Soil analysis based N management

144

+6

6.63

7.08

+2.16

+17.02

46.0

49.2

N management based on agro-ecological zone

150

+12

6.29

7.05

−3.08

+16.53

41.9

47.0

20 kg∙N∙ha−1 at ≤35 SPAD value

60

−78

6.65

5.19

+2.47

−14.21

110.8

86.5

30 kg∙N∙ha−1 at ≤35 SPAD value

90

−48

6.53

6.98

+0.62

+15.37

72.6

77.6

20 kg∙N∙ha−1 at ≤3.0 LCC value

120

−18

7.34

6.87

+13.1

+13.55

61.2

57.3

30 kg∙N∙ha−1 at ≤3.0 LCC value

180

+42

6.72

7.25

+3.54

+19.83

37.3

40.3

Urea super granule (USG)

80

−58

6.24

6.89

−3.85

+13.88

78.0

86.1