Geology The region, in which the site lies, is underlain by a combination of Pilliga Sandstone, Nandewar Basalts and clayey sands from the Purlawaugh formation in addition, to the more recent formations of calcium rich geological groups and Tertiary sandstones. (Ward, 1999). The geology of the area indicates the dominance of fluvial patterns that have resulted in the alluvial fans and soils evident, today. The close proximity of both the current Namoi River and paleo-Namoi, further indicates this influence which is, furthermore evident through the interaction of the basement rocks and the episodic alluvial and colluvial events, represented within the soil profile. (Ward, 1999).
Soil The collective term “cracking clays” (McGarry et al, 1989 and Ward, 1999) has been used extensively in literature to describe the soils within the Narrabri landscape. Other studies were more specific in breaking the region into areas of Gilgai dominant, grey clays with or without gypsum and alluvial wash (Ward, 1999). However most reports suggest the greatest influence of soil development is the episodic washing of sediments and hence, the soil being dominated by alluvium and associated formative processes.
	Initially inspection of the site would support previous characterizations of the soil being cracking clay and a dark one of that. However, more specifically a 2 metre deep representative soil pit was dug within the site, that was investigated and determined to be an Epicalcarous epipedal Black Vertosol ., which can be translated as a black self-mulching, cracking clay with evidence of calcium at depth and crusting on the surface.

Further features of the soil are shown below; they suggest a strongly structured soil profile as evident by the strong or very strong pedality and the presence of organic matter.

This soil is representative of many within the district and is important agriculturally. Under irrigation and natural precipitation, the high content allows for soil moisture to be held strongly for prolonged periods of time, reducing potential deep drainage. Overall, it is a well structured soil with no evidence of salinity, only periodic wetting and hence, the a good soil medium for optimal plant growth.

Vegetation

Scattered remnant vegetation on cleared lands:
Ironbark (Eucalyptus creba)
White cypress pine (Callitris columellaris)
White box (Eucalyptus albens)

Grasses and Grasslands:
Rough Speargrass (Stipa scabra)
Slender Bamboo Grass (Stipa verticellata)
Corkskrew Grass (Stipa setacea)
Curly Windmill Grass (Enteropogon acicularis)
Wire Grass (Aristida sp.)

Weeds:
Wild Turnip (Lepidium)
Common Vetch (Vicia sativa)
Rolypoly (Bassia quinquecuspis)
Varigrated Thistle (Silybum marianum)
Castor Oil Plant (Ricinus communis)

Dry Sclerophyll Forests:
Bimble Box (Eucalyptus populnea)
Wilga (Geijera parviflora)
Belah (Casurina cristata)

Landuse

The Narrabri district is represented by irrigated agriculture, specifically summer crops namely, cotton and cereals (McGarry et al, 1989). Cotton is the regions largest commodity and employs a large proportion of the regions workforce, second to that are cattle and irrigated grain production . Within the region, significant proportion of land remains in a contempory natural state which is represented by scrubby bush land and native forest. However most land in the area has been cleared for agriculture.

References

McGarry, D., Ward, W.T., and McBratney, A.B. 1989. Soil Studies in the Lower Namoi Valley: Methods and Data 1: The Edgeroi Data Set. CSIRO Division of Soils.

Ward, T. 1999. Soils and Landscapes near Narrabri and Edgeroi, NSW, with data analysis using fuzzy k-means. CSIRO Land and Water Technical Report 22/99, 1999.