Plot |
Texture |
Depth |
pH |
CEC |
EC |
ESP |
OC |
N |
P |
|
|
( cm ) |
|
|
|
|
|
|
|
7 |
clay |
0-10 |
6.9 |
34.8 |
0.06 |
1.3 |
2.1 |
4 |
20 |
|
clay |
30-50 |
7.6 |
46.8 |
0.09 |
3.6 |
1.0 |
< 1 |
< 5 |
Note – pH ( 1:5 water ), CEC – cmol (+)/ kg , EC - DS / m , ESP – Sodium per cent of cations , OC – Organic Carbon per cent ( Walkely & Black ), N – Nitrate Nitrogen ( mg / kg ), P – Phosphorus ( Colwell )
Table 16 : Soil analysis for Tabletop plot 7
Soils are clays with a pH in the range 6.9 – 7.6 with CEC rating suggesting reasonable availability of nutrients while EC ratings are low . Organic carbon is high in plot 7 ( for agricultural soils in Queensland ) and phosphorus is high in the topsoil .
Figure 31 : Black soil site Plot 7
Plot 7 was predominantly B . pertusa with negligible amounts of Chrysopogon fallax , forbs and native legumes . The gully floors in plot 7 were colonised by a mixture of Indian couch and Angleton grass ( Dichanthium aristatum ) and , eventually butterfly pea by May 2022 , due to the quality and depth of the black cracking clay .
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