Coefficient

Recommended nutrient rate

EORs at five N, P and K/grain price ratios

a

b

c

EOR†

Rec‡

CP = 8

CP = 6

CP = 5

CP = 4.5

CP = 3.5

Season

Mg·ha⁻¹

kg/ha

Nitrogen

kg·ha⁻¹

N_2015

3.85

1.62

0.995

92

1

48

87

110

164

N_2016

6.16

2.74

0.997

9

105

166

201

285

N_Comb S_S

3.94

1.16

0.988

82

48

71

85

96

116

PCR (US$)

3.94

1.16

0.988

0.38

0.62

0.81

0.90

1.22

Phosphorus

CP = 18

CP = 10

CP = 7

CP = 5.5

CP = 4.5

P_2014

4.91

1.30

0.937

20

24

33

38

44

45

P_2015

3.25

0.67

0.049

2

2

2

2

2

P_2016

3.71

0.82

0.834

12

15

17

18

19

P_Comb S_S

3.90

0.81

0.838

16

12

15

17

18

20

PCR (USD)

3.90

0.81

0.838

2.33

4.07

5.55

6.88

7.78

Potassium

CP = 8

CP = 6

CP = 5

CP = 4.5

CP = 4

K_2014

5.21

1.49

0.995

0

0

44

80

101

125

K_2016

3.22

0.85

0.273

4

4

4

4

4

K_Comb S_S

3.40

0.70

0.968

44

32

41

46

50

53

PCR (USD)

3.40

0.70

0.968

0.76

1.07

1.35

1.44

1.69