Academic literature on the topic 'Soils South Australia McLaren Vale'

Platypuses were once common through many waterways of South Australia but now only live in a small system of rivers on Kangaroo Island where they were introduced in 1940. There is renewed interest from individuals and organisations in re-establishing the species in areas of mainland South Australia. The main objective of this project is to identify essential criteria for maintaining platypuses in South Australian ponds. Platypuses were captured on Kangaroo Island and introduced into a two pond system at McLaren Vale south of Adelaide. The animals were radio tagged and their behaviour monitored. Prior to introduction the habitat was fenced to exclude foxes and feral cats. The ponds were improved by the removal of mosquito fish and trout, placement of snags in the water, planting of aquatic vegetation at the margin and management of the water volume and surface area. Observations indicated that soft moist soil at water level aids the creation of burrows and refuges which may take months to establish. In the interim platypuses will make use of natural earth cracks or create refuges in vegetation. The animals are active in the grassy surrounds, move freely between ponds and feed on supplements of mealworms and earthworms. Key requirements for establishing platypuses in pond systems will include the exclusion of mammalian predators, providing a habitat conducive to the establishment of burrows and optimising food availability.

A case study of the McLaren Vale wine industry is used to challenge four areas of the regulation debate. First, the uniqueness of some of the key features underpinning the periodisations of accumulation regimes and their associated modes of social regulation is questioned. Second, concern is raised over the extent to which ‘new industrial districts’ can really be described as engaging in ‘new’ practices. Third, the importance of local regulatory mechanisms is emphasised. Last, the importance of nonstate, nonlegislative forms of regulation are highlighted.

The evaluation of 6 clonal selections of Sauvignon blanc grapes grown at McLaren Vale in South Australia identified 2 significantly (P<0.05) higher yielding clones, F4V6 and F14V9. F4V6 and F14V9 had significantly lower total soluble solids TTS) in the years where all clones were harvested together. In 1 year, F4V6 and F14V9 were harvested 9 days later than the remaining clones. Their TSS values were not significantly different, The titratable acidities of F4V6 and F14V9 were lower due to lower tartrate and malate levels. The pH of F4V6 was higher than that of any other clone at a similar maturity level. (Clones F4V6 and F14V9 had greater yields per vine in all 3 years.

Aim: To analyse unmanned aerial vehicle (UAV)-based imagery to assess canopy structural changes after the application of different canopy management practices in the vineyard.Methods and results: Four different canopy management practices: i–ii) leaf removal within the bunch zone (eastern side/both eastern and western sides), iii) bunch thinning and iv) shoot trimming were applied to grapevines at veraison, in a commercial Cabernet-Sauvignon vineyard in McLaren Vale, South Australia. UAV-based imagery captures were taken: i) before the canopy treatments, ii) after the treatments and iii) at harvest to assess the treatment outcomes. Canopy volume, projected canopy area and normalized difference vegetation index (NDVI) were derived from the analysis of RGB and multispectral imagery collected using the UAV. Plant area index (PAI) was calculated using the smartphone app VitiCanopy as a ground-based measurement for comparison with UAV-derived measurements. Results showed that all three types of UAV-based measurements detected changes in the canopy structure after the application of canopy management practices, except for the bunch thinning treatment. As expected, ground-based PAI was the only technique to effectively detect internal canopy structure changes caused by bunch thinning. Canopy volume and PAI were found to better detect variations in canopy structure compared to NDVI and projected canopy area. The latter were negatively affected by the interference of the trimmed shoots left on the ground.Conclusions: UAV-based tools can provide accurate assessments to some canopy management outcomes at the vineyard scale. Among different UAV-based measurements, canopy volume was more sensitive to changes in canopy structure, compared to NDVI and projected canopy area, and demonstrated a greater potential to assess the outcomes of a range of canopy management practices. Significance and impact of the study: Canopy management practices are widely applied to regulate canopy growth, improve grape quality and reduce disease pressure in the bunch zone. Being able to detect major changes in canopy structure, with some limitations when the practice affects the internal structure (i.e., bunch thinning), UAV-based imagery analysis can be used to measure the outcome of common canopy management practices and it can improve the efficiency of vineyard management.

Drip irrigation is the most common method of water application used in Australian vineyards. However it places physical and chemical stress upon soil structure, which may affect soil physical properties, soil water availability and grapevine functioning. Common soil types within Australian vineyards appear vulnerable to soil degradation and there is emerging evidence of such degradation occurring. Two South Australian vineyards (one located at Nuriootpa in the Barossa Valley, the other in the McLaren Vale winegrowing region) were used to examine evidence of altered soil physical properties due to irrigation. Significantly higher soil strength and lower permeability was found under or near the dripper in irrigated soils. There was also evidence that irrigation increased subsoil bulk density at Nuriootpa. It was uncertain how irrigation caused these changes. While sodicity was present at Nuriootpa, it appeared the physical pressures exerted by irrigation, such as rapid wetting and prolonged wetness, also contributed. To gauge the severity of the degradation at Nuriootpa, a modelling study assessed the impact of higher soil strength and salinity on grapevine transpiration. The SWAP model (Soil- Water-Atmosphere-Plant) was modified and then calibrated using soil moisture data from Nuriootpa. Simulations were conducted for different irrigation regimes and the model output indicated that degradation led to a reduction in cumulative transpiration, which was almost entirely due to higher soil strength. However the reduction was relatively minor and there was evidence of water extraction by roots in all soil layers. Hence the degradation, in terms of higher soil strength and salinity, was not considered a significant management problem in the short - term. Evidence of increased waterlogging and its consequences require further investigation. Roots were observed in soils at Nuriootpa with penetration resistance (PR) much greater than 2 MPa, which was thought to completely impede grapevine root growth. It was hypothesised that roots avoided the physically hostile matrix by using biopores or structural cracks. A pot experiment tested this hypothesis and examined the relationship between soil strength, biopores and root growth for grapevines. Grapevine rootlings (cv. Cabernet Sauvignon) were grown into pots with varying degrees of soil compaction, with and without artificial biopores. No root growth occurred when PR>2 MPa unless biopores were present. Pores also improved root growth in non-compacted soil when PR approached 1 MPa, which suggested biopores influence root growth in soils regardless of compaction levels. Therefore PR should not be the only tool used to examine the rooting-potential of a vineyard soil. An assessment of soil structure, such as biopore density and size, should be incorporated. In drip-irrigated vineyards, there is a possibility that degraded clayey subsoils could be ameliorated by manipulating zones of soil drying. At distances away from the dripper, drying events could generate shrinkage cracks that improve drainage and provide opportunities for root growth. From a practical perspective, drying events could be manipulated by moving the dripper laterally or by changing the irrigation frequency and intensity. The potential of this simple, non-invasive, ameliorative approach was investigated. Large, intact cores were sampled from Nuriootpa subsoil where degradation had been identified. Individual core bulk density was calculated using a formula that was derived by solving two common soil physics equations simultaneously. This proved to be an accurate and non - invasive method. Half the cores were leached with a calcium solution, and the saturated hydraulic conductivity (K [subscript s] ) was measured on all cores before and after drying to a matric potential of -1500 kPa. Soil drying led to a significant increase in K [subscript s], which indicated an improvement in structure through the creation of shrinkage cracks and heaving. Calcium treatment had no impact on K [subscript s], but that could change with more wetting and drying cycles. Results indicated the need for further investigation in the field, where different compressive and tensile forces operate. Harnessing this mechanism may provide an attractive soil management option for growers. The soil physical degradation identified is concerning for sustainable production in irrigated vineyards. Given the sites were representative of typical irrigation practices, such degradation may be widespread. While modelling suggested the impact of higher soil strength and salinity was minimal, these properties should be monitored because they may worsen with continuing irrigation. Furthermore, the impact of irrigation on subsoil permeability needs to be defined more accurately. An increased incidence of waterlogging could significantly restrict production, which was evident when overly wet growing seasons were modelled. If subsoil permeability was found to be significantly lower in irrigated soils, amelioration may be required. In this instance, the use of drying events to generate structure provides an option. Ultimately, the impact of drip irrigation on soil physical quality warrants further attention, and it is imperative to monitor the physical quality of vineyard soils to ensure sustainable production.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007.

Weathering of rocks is the crucial first step in making vineyards possible. For where the debris produced by weathering—the sediment we met in Chapter 5—becomes mixed with moist humus, it will be capable of supporting higher plant life. And thus we have soil, that fundamental prerequisite of all vineyards, indeed of the world’s agriculture. So how does this essential process of weathering come about? Any bare rock at the Earth’s surface is continually under attack. Be it a rocky cliff, a stone cathedral, or a tombstone, there will always be chemical weathering—chemical reactions between its surface and the atmosphere A freshly hewn block of building stone may look indestructible, but before long it will start to look a bit discolored and its surface a little crumbly. We are all familiar with an analogy of this: a fresh surface of iron or steel reacting with moisture and oxygen in the air to form the coating we call rust. In his “Guide to the Lakes” of England, William Wordsworth put the effects of weathering far more picturesquely: “elementary particles crumbling down, over-spread with an intermixture of colors, like the compound hues of a dove’s neck.” A weathered rock is one that is being weakened, broken down. The rock fragments themselves are further attacked, which is why stones in a vineyard often show an outer coating of discolored material, sometimes referred to as a weathering rind (Figure 9.1; see Plate 22). If the stone is broken open, it may show multiple zones of differing colors paralleling the outer surface of the fragment and enclosing a core of fresh rock. Iron minerals soon weather to a powdery combination of hematite, goethite, and limonite, and the rock takes on a reddish-brown, rusty-looking color. The great example of such weathering in viticulture is the celebrated terra rossa, but the rosy soils in parts of Western Australia and places further east such as McLaren Vale and the Barossa Valley are also due to iron minerals. Several Australian wines take their names from this “ironstone.”