Table 2: Critical limits for interpreting fertility levels of soil analytical parameters.
|
Parameter |
Very low |
Low |
Moderate |
High |
Very High |
|
*Ca2+(cmol kg-1) |
|
< 2.0 |
2.1 - 5.0 |
> 5.0 |
|
|
*Mg2+(cmol kg-1) |
|
< 0.30 |
0.31 - 1.0 |
> 1.0 |
|
|
*K+ (cmol kg-1) |
|
< 0.15 |
0.16 - 0.3 |
> 0.3 |
|
|
*Na+(cmol kg-1) |
|
< 0.10 |
0.11 - 0.3 |
> 0.3 |
|
|
CEC (cmol kg-1) |
< 6.0 |
6.0 -12.0 |
12.1 - 25.0 |
25.1 - 40.0 |
> 40.0 |
|
*ECEC (cmol kg-1) |
|
< 6.0 |
6.1 - 12.0 |
> 12.0 |
|
|
EA (cmol kg-1) |
|
< 2.0 |
2.1 - 5 |
> 5 |
|
|
Org. C (%) |
< 0.4 |
0.4 - 1.0 |
1.1 - 1.4 |
1.5 - 2.0 |
|
|
*Total N (%) |
< 0.05 |
0.06 - 0.10 |
0.11 - 0.15 |
0.16 - 0.20 |
> 0.20 |
|
Avl. P (mg kg-1) |
< 3.0 |
3.0 -7.0 |
7.1 - 20.0 |
> 20.0 |
|
|
BS (%) |
< 20 |
20 - 40 |
41 - 60 |
60 - 80 |
80 - 100 |
|
ESP (%) |
< 0.1 |
0.1 - 2.0 |
2.1 - 8.0 |
8.1 - 15.0 |
> 15.0 |
|
*B (mg kg-1) |
|
< 0.2 |
0.21 - 2.0 |
> 2.0 |
|
|
*Zn (mg kg-1) |
|
< 0.8 |
0.81 - 2.0 |
> 2.0 |
|
|
*Mn (mg kg-1) |
|
< 1.0 |
1.1 - 5.0 |
> 5.0 |
|
|
*Fe (mg kg-1) |
|
< 2.5 |
2.51 - 5.0 |
> 5.0 |
|
Source: *Shehu, et al. [48], Enwezor, et al. [49].