Sustainable Practices for Vegetable Production in the South
Dr. Mary Peet, NCSU
Home

Nutrient sources

Nitrogen

%N

Leaching Risk*

Volatilization

Ammonium sulfate

21

low

low

Ammonium nitrate

33

medium

low

Ammonium phosphates

10-18

low

low

Urea

46

low

medium (high if surface applied)

Sodium nitrate

16

high

low

Blood meal

13-15

..

..

*These risks are for N in the ammonium form. Once in the soil, ammonium is converted to nitrate and thus is leachable.

Phosphates

Typical Analysis
N-P-K

Range of
% available P2O5

Superphosphates

0-20-0

16-50

Ammonium phosphate

11-53-0

48-53

Diammonium phosphate

18-46-0

46-53

Steamed bone meal

3-30-0

20-30

Rock phosphate

0-30-0

25-30

Potassium

Typical Analysis
N-P-K

Range of
%K2O

Potassium chloride

0-0-60

48-60

Potassium sulfate

0-0-50

48-50

Sul-Po-Mag

0-0-21-(11Mg)

21-30

Potassium nitrate

13-0-44

44

Greensand

0-0-7

7

Liming materials

Neutralizing value
%CaCO3
Equivalent

Pounds to equal
1 ton of lime

Calcitic lime

100

2000

Burned lime

178

1120

Hydrated lime

134

1490

Magnesium carbonate

119

1675

Dolomitic limestone

95-108

1850-2100

Ground shells

80-88

2200-2500

Basic slag

67-71

2800-3000

Flue dust

96

2100

Rock phosphate

7

-

Wood ashes

40

5000


bridgesj@unity.ncsu.edu