Soil property

Soil nutrient level before amendment application

Soil nutrient levels after different amendment application

Critical values

Organo yield

Poultry manure

NPK

pH

4.8

5.5***

4.97**

4.7*

5.5 - 6.5

Organic carbon%

2.8

3.1***

2.9**

2.6*

>3.0

Bulky density (g·cm⁻¹)

1.39

1.11***

1.23**

1.39*

<1.40

Nitrogen (%)

0.17

1.21***

0.26**

0.17*

>0.25

Phosphorus (mg/kg)

2.4

3.74***

2.45**

2.12*

>1.5

Potassium (cmol·kg⁻¹)

0.19

2.63***

0.21**

0.19*

≥2.0

Calcium (cmol·kg⁻¹)

2.26

2.68**

2.77**

2.99***

≥4.0

Magnesium (cmol·kg⁻¹)

2.72

2.9**

3.22***

2.70*

≥0.5