The application of fertilisers to pastures in the high rainfall regions of southern Australia has contributed to large increases in carrying capacity following the widespread adoption of the practice since the late 1940s. Recently, large shifts in the worldwide demand for fertiliser inputs have lead to large rises in the cost of fertiliser inputs. These increasing costs have significant potential ramifications on the future management of soil fertility and its interaction with the persistence and profitability of sown pastures, especially during periods of climatic uncertainty. Adynamic pasture resource development simulation model was used to investigate the implications of fertiliser rates and costs on the efficient management of soil fertility under climatic uncertainty. The framework also allowed the investigation of how the management of soil fertility interacts with the utilisation of pasture resources through different stocking rates. In the application of this method to the Cicerone Project farmlets case study, fertiliser input costs were found to influence the optimal combination of fertiliser inputs and stocking rate. Analyses of the dynamic interaction between fertiliser application and cost, stocking rate and the persistence of desirable species enabled the identification of the most risk-efficient strategies. The implications for grazing industries in the high rainfall regions of southern Australia are discussed.

Deforestation is a leading cause of biodiversity loss and an important source of global carbon emissions. This means that there are important synergies between climate policy and conservation policy. The highest rates of deforestation occur in tropical countries, where much of the land at the forest frontier is managed informally by smallholders and where governance systems tend to be weak. These features must be considered when designing policies to reduce emissions from deforestation such as REDD +. Deforestation is often accompanied by fires that release large amounts of carbon dioxide. These emissions are especially high in the case of peatlands which contain thick layers of carbon-rich matter. In this paper we derive marginal abatement cost (MAC) curves using data from a farmer survey in Sumatra, where rates of peatland deforestation are high. Comparing these results with farmers' stated willingness to accept payment not to clear forest to establish oil palm suggests that REDD + policies may be more expensive than MAC estimates suggest The extent to which this is true depends on the types of soils being deforested.

The land-use change and forestry sector can be a cost-effective contributor to climate mitigation in at least three ways: providing carbon offsets through carbon sequestration in biomass and soils, reducing emissions of methane and other greenhouse gases, and producing biofuels that replace fossil fuels. The presence of carbon markets should help encourage these activities; however, most carbon trades to date have occurred in the energy sector. A major obstacle to carbon trades from land-use systems is the presence of high transaction costs of converting a carbon offset into a tradable commodity, so the prevailing market carbon prices may not provide enough incentive for adoption. This paper presents a model of the exchange of carbon offsets between a project developer and a group of landholders. The model is solved to derive project feasibility frontiers that show the minimum number of contracts necessary to make a project feasible at any given carbon price. The model is applied to two case studies (smallholder agroforestry in Indonesia and partial reforestation of family farms in Australia) under two types of contract (purchase of carbon flows and rental of carbon stocks). The paper concludes by identifying possible strategies to reduce transaction costs while maintaining project integrity.

Cassava is an important tropical root crop for food security and national economies. In Ghana, the roots are used in popular local cuisines as well as in brewery, bakery, confectionery and plywood industries. A number of high-yielding and disease-resistant varieties are released and promoted to increase productivity and improve rural welfare. The study used a sequential mixed-method approach to identify, among drivers and impediments, the dissemination mechanism with highest impact on the adoption of improved cassava varieties (ICVs) and its intensity. The analyses helped estimate the impact of ICV adoption on productivity and households' livelihood, and to provide evidence of technological, managerial, and environmental gaps between adopters and non-adopters. Data were collected in 2014 from 608 randomly selected cassava-producing households in 14 communities in six districts of the Ashanti and Brong-Ahafo regions. Summary statistics reveal a 25 percent ICV adoption rate. Econometric analyses indicate significant and positive effects on the likelihood of households' ICV adoption for group members, the number of varieties planted, the number of livestock owned and information received mostly through innovation platforms (IPs). Impediments to ICV adoption include the location in the Ashanti region, household size, distances to the nearest tarred road and market, and grey-skin colour of ICVs. Results from propensity score matching and instrumental variable approaches indicate positive impacts of ICV adoption on cassava and whole-farm productivities and on per-capita annual crop income. Adopters appear to incur lower total annual per-capita expenditures and expenditures on food than non-adopters but spend more on children’s education. Bias-corrected stochastic output distance functions and stochastic metafrontier production functions showed strong evidence of technological, managerial, and environmental gaps between adopters and non-adopters in both cassava and whole-farm production. In both cases, adopters were found to operate on higher frontiers and to be more efficient than non-adopters. Adopters also appear to operate in a more favourable 2 production environment than non-adopters. The study provides strong evidence of inefficiency in cassava production for both ICV adopters and non-adopters. Findings imply that policy measures could be taken to increase the 25 percent ICV adoption rate through the establishment of IPs, focusing on households in Brong-Ahafo and those who are group members that integrate livestock-farming with cassava production. ICV adoption is expected to lead to increased productivity through technological change and enhanced efficiency. Moreover, the adoption of ICVs has the potential to increase crop incomes, food security and result in higher investment in children’s education, especially for female-headed households.

Green Power schemes offer electricity generated by recently constructed renewable energy sources to customers for a higher price than ordinary electricity. This study examines the place of Green Power in the electricity supply industry and among policies to counter global warming, the demand and supply characteristics of Green Power, its effectiveness and measures which could increase its sales. Although growing rapidly, Green Power sales are less than 0.5% of total electricity sales in Australia. The wide variation in market penetration between jurisdictions and between countries for Green Power, the discrepancies between stated willingness-to-pay surveys and actual sales and the low awareness of Green Power found by surveys indicate that Green Power sales could be increased by appropriate marketing and government policies. A sample of 250 pooled time series and cross sectional observations was used to estimate a statistically significant elasticity of demand for residential customers for Green Power with respect to price of -0.96. Green Power schemes appear not to be necessarily loss-making activities for retailers. There has been ample generating capacity for Green Power to meet the growing sales to customers to date. The most cost effective means to increase sales was found to be advertising campaigns such as the campaign in Victoria in 2005. It was also found that full tax deductibility of the Green Power premium to residential customers, an exemption of the Green Power premium from the Goods and Services Tax and a tax rebate for Green Power are probably less cost-effective for promoting sales than direct government purchase of Green Power in terms of cost of policy per unit of increased sales. Green Power plays a small but important role as one amongst a number of climate change policies and the potential of this role is yet to be fully realised.

Two prerequisites for realistically embarking upon an eradication programme are that cost-benefit analysis favours this strategy over other management options and that sufficient resources are available to carry the programme through to completion. These are not independent criteria, but it is our view that too little attention has been paid to estimating the investment required to complete weed eradication programmes. We deal with this problem by using a two-pronged approach: 1) developing a stochastic dynamic model that provides an estimation of programme duration; and 2) estimating the inputs required to delimit a weed incursion and to prevent weed reproduction over a sufficiently long period to allow extirpation of all infestations. The model is built upon relationships that capture the time-related detection of new infested areas, rates of progression of infestations from the active to the monitoring stage, rates of reversion of infestations from the monitoring to active stage, and the frequency distribution of time since last detection for all infestations. This approach is applied to the branched broomrape ('Orobanche ramosa') eradication programme currently underway in South Australia. This programme commenced in 1999 and currently 7450 ha are known to be infested with the weed. To date none of the infestations have been eradicated. Given recent (2008) levels of investment and current eradication methods, model predictions are that it would take, on average, an additional 73 years to eradicate this weed at an average additional cost (NPV) of $AU67.9m. When the model was run for circumstances in 2003 and 2006, the average programme duration and total cost (NPV) were predicted to be 159 and 94 years, and $AU91.3m and $AU72.3m, respectively. The reduction in estimated programme length and cost may represent progress towards the eradication objective, although eradication of this species still remains a long term prospect.

Green Power schemes offer electricity from renewable energy sources to customers for a higher price than ordinary electricity. This study examines the demand characteristics of Green Power in Australia and policies which could increase its sales. A sample of 250 pooled time series and cross sectional observations was used to estimate a statistically significant elasticity of demand for Green Power with respect to price of -0.96 with a 95% confidence interval of ± 68%. The wide variation in market penetration between jurisdictions and between countries for Green Power, and the low awareness of Green Power found by surveys indicate that Green Power sales could be increased by appropriate marketing and government policies. The most cost effective means to increase sales was found to be advertising campaigns although only one Australian example was found, in the state of Victoria in 2005. It was also found that full tax deductibility of the Green Power premium to residential customers, exemption from the Goods and Services Tax and a tax rebate for Green Power are all probably less cost effective for promoting sales than direct government purchase of Green Power, in terms of cost per unit of increased sales.

This study addresses the problem of balancing the trade-offs between the need for animal production, profit, and the goal of achieving persistence of desirable species within grazing systems. The bioeconomic framework applied in this study takes into account the impact of climate risk and the management of pastures and grazing rules on the botanical composition of the pasture resource, a factor that impacts on livestock production and economic returns over time. The framework establishes the links between inputs, the state of the pasture resource and outputs, to identify optimal pasture development strategies. The analysis is based on the application of a dynamic pasture resource development simulation model within a seasonal stochastic dynamic programming framework. This enables the derivation of optimum decisions within complex grazing enterprises, over both short-term tactical (such as grazing rest) and long-term strategic (such as pasture renovation) time frames and under climatic uncertainty. The simulation model is parameterised using data and systems from the Cicerone Project farmlet experiment. Results indicate that the strategic decision of pasture renovation should only be considered when pastures are in a severely degraded state, whereas the tactical use of grazing rest or low stocking rates should be considered as the most profitable means of maintaining adequate proportions of desirable species within a pasture sward. The optimal stocking rates identified reflected a pattern which may best be described as a seasonal saving and consumption cycle. The optimal tactical and strategic decisions at different pasture states, based on biomass and species composition, varies both between seasons and in response to the imposed soil fertility regime. Implications of these findings at the whole-farm level are discussed in the context of the Cicerone Project farmlets.

Agroforests managed by smallholders have been shown to provide biodiversity, carbon-storage and rural-livelihood services. Consequently, these systems are being promoted as an effective way of rehabilitating millions of hectares of degraded, formerly forested land in many tropical countries. Current conditions at the forest margins in these countries, however, make it easier to clear unprotected forests than restore degraded lands through agroforestry. The result is large-scale deforestation that causes substantial losses of biodiversity and stored soil and biomass carbon. Agroforests will only be an attractive activity if they are financially viable and socially acceptable. In this study we investigate the financial viability of agroforestry systems as carbon sinks when carbon-credit payments are available. A meta-modelling framework is adopted, comprising an econometric-production model of a land parcel in Sumatra, Indonesia. The model is used within a dynamic-programming algorithm to determine optimal management of the system in terms of three decision variables: tree/crop area, tree-rotation length, and wood harvest. Results show the influence of soil-carbon stocks and discount rates on optimal strategies and reveal interesting implications for joint management of agriculture and carbon as well as for the possible restoration of degraded land.

Government funding to protect native plant communities is usually limited. For cost effectiveness, priority sites for conservation must therefore be identified and funds allocated to protect these sites according to the quantity of communities conserved per dollar of cost. In 1999, invasion of coastal vegetation in New South Wales (NSW) by bitou bush was listed as a key threatening process under the NSW 'Threatened Species Conservation Act' 1995. In accordance with the Act, a Threat Abatement Plan (TAP) was prepared to reduce the impacts of the weed to threatened biodiversity at priority sites. In the present study, data collected for the TAP were analysed by linear programming to determine the feasibility of achieving cost effectiveness in identifying sites and allocating funds, and to explore the impact of associated economic issues on the quantity of native plant communities that are protected. In addition to the total funds and costs per site, the quantity was influenced by alternative funding policies and different site selection strategies. Allocations that recognise these issues can enhance protection outcomes, and promote the cost effectiveness of weed management.