Remote Sensing for Site-Specific Crop Management: Evaluating the Potential of Digital Multi-Spectral Imagery for Monitoring Crop Variability and Weeds within Paddocks

This paper analyses the potential and limitations of airborne remote sensing systems for detecting crop growth variability and weed infestation within paddocks at specified capture times. The detection of areas of crop growth variability can help farmers become aware of regions within their paddock where they may be experiencing above and below average yields due to changes in soil or management conditions. For instance, the early detection of weed infestation within cereal crops is crucial for lessening their impact on the final yield. Transect sampling within a canola paddock of a broad acre agricultural property in the South West of Western Australia was conducted synchronous with the capture of 1m spatial resolution DMSI. The four individual bands (blue, green, red and near- infrared) of the DMSI were correlated with LAI and weed density counts collected in the paddock. Statistical analyses show the LAI of canola had strong negative correlations with the blue (-0.93) and red (-0.89) bands and a strong positive correlation was found with the near-infrared band (0.82). The strong correlations between the canola LAI and selected bands of the DMSI indicate that this may be a suitable technique for monitoring canola variability to derive information layers that can be used in creating meaningful "within-field" management units. Likewise, DMSI could be used as a non-invasive tool for in season crop monitoring. The correlation analysis with the weed density (e.g. self sown wheat, ryegrass and clover) attributed to only one negative weak correlation with the red band (-0.38). The less successful detection of weeds is attributed to the minimal weeddensity within the paddock (e.g. mean 34 plants m-2) and indistinct spectral difference from canola at the early time of imagery capture required by farmers for effective variable rate applications of herbicides.LAI, remote sensing, crop density, vegetation indices, weed mapping., Crop Production/Industries,

Assessing chronological changes in remnant native forest at catchment level : a case study on the Toolibin catchment area

The aim of this study were to construct a digital database of the historical patterns of land clearing (amount, spatial distribution); to reconstruct the historical vegetation of the Toolibin catchment, Western Australia, using mallet maps and reports of the period; to produce maps showing the rate of clearing for the periods 1960-70, 1970-80, 1980-96; and to analyse the relationships between soil types, topographic position and land clearing

Synergies between Land Degradation Neutrality goals and existing market-based instruments

© 2019 Since the concept of the Land Degradation Neutrality (LDN) emerged in global policy discourse, a key point of contention has been the development of market-based instruments to promote the LDN agenda. Much of this discussion has focused on the use of LDN-specific offset mechanisms and private-public partnerships. However, there is also an opportunity to capitalise on the synergies that exist between LDN objectives and those of existing market-based instruments that have previously been developed for carbon, biodiversity, bioenergy and in other contexts. LDN objectives could be integrated into such schemes through targeted eligibility rules and certification schemes, supporting methodologies, adaptations to multifunctional indices used in auction-based approaches and the restructuring of mandates, tax breaks and feed-in tariffs for bioenergy and other products

'This country just hangs tight': Perspectives on managing land degradation and climate change in far west NSW

© 2019 Australian Rangeland Society. Discussions of land degradation often display a disconnect between global and local scales. Although global-scale discussions often focus on measuring and reversing land degradation through metrics and policy measures, local-scale discussions can highlight a diversity of viewpoints and the importance of local knowledge and context-specific strategies for sustainable land management. Similarly, although scientific studies clearly link anthropogenic climate change to land degradation as both cause and consequence, the connection may not be so clear for local rangelands communities due to the complex temporal and spatial scales of change and management in such environments. In research conducted in October 2015, we interviewed 18 stakeholders in the far west of New South Wales about their perspectives on sustainable land management. The results revealed highly variable views on what constitutes land degradation, its causes and appropriate responses. For the pastoral land managers, the most important sign of good land management was the maintenance of groundcover, through the management of total grazing pressure. Participants viewed overgrazing as a contributor to land degradation in some cases and they identified episodes of land degradation in the region. However, other more contentious factors were also highlighted, such as wind erosion, grazing by goats and kangaroos and the spread of undesired 'invasive native scrub' at the expense of more desirable pasture, and alternative views that these can offer productive benefits. Although few participants were concerned about anthropogenic climate change, many described their rangeland management styles as adaptive to the fluctuations of the climate, regardless of the reasons for these variations. Rather than focusing on whether landholders 'believe in' climate change or agree on common definitions or measurement approaches for land degradation, these results suggest that their culture of adaptation may provide a strong basis for coping with an uncertain future. The culture of adaption developed through managing land in a highly variable climate may help even if the specific conditions that landholders need to adapt to are unlike those experienced in living memory. Such an approach requires scientific and expert knowledge to be integrated alongside the context-specific knowledge, values and existing management strategies of local stakeholders

A semi-automated approach for GIS based generation of topographic attributes for landform classification

This paper presents LANDFORM, a customized GIS application for semi-automated classification of landform elements, based on landscape parameters. Using custom commands, topographic attributes like curvature or elevation percentile were derived from a Digital Elevation Model (DEM) and used as thresholds for the classification of Crests, Flats, Depressions and Simple Slopes. With a new method, Simple Slopes were further subdivided in Upper, Mid and Lower Slopes at significant breakpoints along slope profiles. The paper discusses the results of a fuzzy set algorithm that was used to compare the similarity between the map generated by LANDFORM and the visual photo- interpretation conducted by a soil expert over the same area. The classification results can be used in applications related to precision agriculture, land degradation studies, and spatial modelling applications where landform is identified as an influential factor in the processes under study

Comparison of Alternative Strategies for Invasive Species Distribution Modeling

Species distribution models (SDMs) can provide useful information for managing biological invasions,such as identification of priority areas for early detection or for determining containment boundaries.However, prediction of invasive species using SDMs can be challenging because they typically violatethe core assumption of being at equilibrium with their environment, which may lead to poorly guidedmanagement resulting from high levels of omission. Our goal was to provide a suite of potential decisionstrategies (DSs) that were not reliant on the equilibrium assumption but rather could be chosento better match the management application, which in this case was to ensure containment throughadequate surveillance. We used presence-only data and expert knowledge for model calibration andpresence/absence data to evaluate the potential distribution of an introduced mesquite (Leguminoseae:Prosopis) invasion located in the Pilbara Region of northwest Western Australia. Five different DSs withvarying levels of conservatism/risk were derived from a multi-criteria evaluation model using orderedweighted averaging. The performance of DSs over all possible thresholds was examined using receiveroperating characteristic (ROC) analysis. DSs not on the convex hull of the ROC curves were discarded. Twothreshold determination methods (TDMs) were compared on the two remaining DSs, one that assumedequilibrium (by maximizing overall prediction success) and another that assumed the invasion was ongoing(using a 95% threshold for true positives). The most conservative DS fitted the validation data mostclosely but could only predict 75% of the presence data. A more risk-taking DS could predict 95% of thepresence data, which identified 8.5 times more area for surveillance, and better highlighted known populationsthat are still rapidly invading. ThisDSandTDMcoupling was considered to be the most appropriatefor our management application. Our results show that predictive niche modeling was highly sensitiveto risk levels, but that these can be tailored to match specified management objectives. The methodsimplemented can be readily adapted to other invasive species or for conservation purposes

The role of electric vehicles in decarbonising Australia's road transport sector: modelling ambitious scenarios

Transitioning to net-zero greenhouse gas (GHG) emissions by 2050 is becoming increasingly urgent, requiring accelerated efforts to decarbonise all economic sectors, including transport, a growing emissions source. A transition to battery electric vehicles (BEV) would accelerate the decarbonisation of road transport and provide other benefits. But in Australia, BEV uptake has been negligible, and the scale and pace required to reach net-zero emissions by 2050 has not been addressed to date. This study applies a national-scale integrated macroeconomic model (iSDG-Australia) to project Australia's future road transport demand, vehicle mix, energy consumption and GHG emissions by 2050. It models five scenarios incorporating different levels of economic and population growth, vehicle longevity, ambitions for BEV uptake, fleet renewal, forced phase-out of fossil-fuelled vehicles and shifts to renewable electricity. Scenario projections are benchmarked on their zero-emission vehicle mix, fuel and electricity consumption, GHG emissions, and broader social and economic impacts. We conclude the scale and pace of change must be transformational rather than transitional, requiring urgent policy action. An ambitious and rapid transition to 100% BEVs in new vehicle sales, accelerated fleet renewal, and a shift to renewable electricity generation could achieve a net-zero outcome for Australia's road transport sector by 2050

Transforming Australia's road fleet with electric vehicles: Strategies and impediments affecting net-zero emissions targets for 2050

A complete and rapid transition to electromobility can minimise road fleet emissions. Electric vehicles (EV) will be essential for decarbonising road transport, which in 2022 generated 19% of Australia's total emissions. Unlike New Zealand, which implemented multiple policies since 2016, limited policy support in Australia for EVs means uptake lags. Creating opportunities for decarbonising road transport and the electricity supply could accelerate the clean energy transition and reduce fossil-fuel dependence. This paper's primary purpose is to suggest policy mechanisms to expedite Australia's road fleet electrification by 2050. Results show that implementation of evidence-based policies, and ensuring their ongoing functionality, will be necessary to achieve the goal. We provide recommendations for the future direction of Australia's federal government policy to enhance a rapid transition to EVs. Its role is critical in supporting the transformation by adopting appropriate targets and policies to encourage EV uptake, transitioning electricity completely to renewable sources, deploying adequate charging infrastructure and maintaining it and the forced-phase out of residual fossil-fuelled cars. A faster transition means fewer emissions and less likelihood of exceeding the emissions budget

Accelerating electric vehicle uptake: Modelling public policy options on prices and infrastructure

Transitioning to passenger battery electric vehicles (BEV) can mitigate climate change impacts of road transportation. We develop a novel BEV policy model, nesting it within a national-scale macroeconomic system dynamics model (iSDG-Australia) to simulate a suite of policy pathways. We model combinations of infrastructure support and subsidies, which bring forward the price-parity tipping point, thus rapidly accelerating BEVs’ share of new car sales. However, ongoing complementary charging infrastructure investment is critical to reach 100% new BEV car sales by 2050 in Australia. Even with a rapid transition, the modelled fleet would not achieve net-zero greenhouse gas emissions by 2050 due to vehicle longevity; and suddenly ceasing financial incentives could retard BEV sales by a decade. Based on our assumptions, results suggest emissions reductions are maximised by the fastest transition of the passenger vehicle fleet to BEVs, entailing government policy support from 2020 to 2050, for both adequate infrastructure deployment (AUD17.9b) and vehicle rebates (AUD19.5b), which achieves earlier BEV price-parity with fossil-fuelled vehicles

Multi-temporal remote sensing of ground cover reveals beneficial effects of soil carbon farming in a semi-arid landscape

Sustainable land management practices are a strategic tool for addressing land degradation processes that threaten agroecosystem services supply. Currently, carbon credit schemes are important promoters of the adoption of such practices, yet their effectiveness on providing services other than carbon sequestration is not frequently assessed. Particularly, vegetation cover may not only be a mediator of CO2 fixation, but also act as protection against soil erosion and prevent water quality deterioration. The overarching aim was to develop generalizable methods to assess the effectiveness of sustainable land management practices for maintaining agroecosystem integrity. To achieve this, we assessed the effect of soil carbon sequestration practices on remotely sensed groundcover levels and its stability, and on its response to short-term antecedent accumulated rainfall. These methods were tested in the Cowra Trough, an agricultural region of semi-arid New South Wales, Australia. Time series statistics (mean and standard deviation) and non-parametric tests were used to analyse temporal change in remotely sensed groundcover on paddocks undergoing different land management change intensities. This was complemented with a regional scale analysis of the effect of land use to contextualize paddock-scale results. Moreover, sequential linear regressions of remotely sensed vegetation cover response to antecedent rainfall through a moving temporal window were employed to assess trends in this relationship. A significant effect of land management change was demonstrated: over 90% of the sites implementing sustainable practices had increased and more stable ground cover levels, and the same number (though not the same sites) decreased their ground cover dependence on rainfall. The size of the effect was not related to the intensity of management change implemented for soil carbon sequestration. Land use type proved to be an important spatiotemporal predictor of ground cover and its stability at the Cowra Trough scale with cropping performing worse than grazing systems. Notably, the implementation of carbon farming practices was found to have a more prevalent positive impact on ground cover than on soil carbon contents, suggesting that such practices may provide co-benefits even when no carbon sequestration occurred. This study advances the possibility of monitoring agroecosystem multifunctionality and the development of integrative ‘payment for ecosystem services’ schemes