Rehabilitating open-cut coal mine spoil for a pasture system in south east Queensland, Australia: Abiotic soil properties compared with unmined land through time

Sustainability of beef production from brigalow lands after cultivation and mining. 2. Acland Grazing Trial pasture and cattle performance

“…DMD, dry matter digestibility; N, nitrogen; P, phosphorus parallel studies. Detailed assessments of the soil and pasture characteristics of the Control paddock were compared with those in surrounding unmined land (Bennett et al 2021;Paton et al 2021), and productivity comparisons of the grazing system were assessed through modelling and simulation studies (Clewett et al 2021). Key findings of these parallel studies are highlighted in the present study.…”

“…The soil in the Control paddock was a Brown Dermosol (Isbell 2002) representative of Dermosols and Vertosols in surrounding unmined land, and the soil profiles in the Rehab paddocks were classified as Spolic Anthroposols (Bennett et al 2021). Plant-available soil phosphorus (P) in the Control paddock (Colwell P, 0-60 cm, mean 5 mg/kg) was lower than in other unmined sites across the mining lease (mean 23 mg/kg) and the Rehab paddocks (means 29, 35 and 12 mg/kg in Rehab 1, Rehab 2 and Rehab 3 respectively), but was within the ranges measured across those sites.…”

“…The Control paddock had a history of cultivated cropping and was on a Brigalow Uplands land type derived from Walloon sandstones. Soils on this land type typically have low fertility (Bennett et al 2021). As a consequence, the Control paddock soil was nutrientdepleted and pasture and cattle productivity was not expected to be high.…”

“…Since mining began, unmined land on the mining lease has been used mainly for beef cattle grazing and, partially, for dryland winter wheat and barley cropping. The land is within the Acland Land System (Vandersee and Mullins 1977), and the lease sits on the Poplar Box Walloon landform, which supports several land resource areas, including the Brigalow Uplands on which the majority of mining has occurred (Bennett et al 2021). Brigalow Uplands typically support brigalow (Acacia harpophylla), belah (Casuarina cristata) and wilga (Geijera parviflora) open forest vegetation on soils derived from the Walloon sandstones but also Mountain Coolibah (Eucalyptus orgadophila) and softwood scrub species such as bottle tree (Brachychiton) and crows ash (Flindersia australis) with brigalow on basalt rises.…”

“…This paper evaluates measured key performance indicators of pasture and livestock productivity on the basis of field data from Botanal pasture assessments, cattle weights, and pasture and faecal indicators of diet quality. The paper also draws on performance indicators evaluated in companion papers for soil (Bennett et al 2021), pasture carrying capacity (Paton et al 2021), and economic viability and long-term sustainability modelled using GRASP (Clewett et al 2021).…”