Quantification Of Risk Reduction Research Articles

Reducing risk through crop diversification: An application of portfolio theory to diversified horticultural systems

In agricultural sciences, it is frequently stated that diversified systems are more likely to cope with risks, but rarely demonstrated in a quantitative way. On the theoretical perspective, risk reduction based on asset diversification is a well studied mechanism in economics that has been formalized in the Modern Portfolio Theory (MPT). In this paper, we thus explore the opportunities for application of MPT to quantify the benefits of diversification for risk reduction in a context of highly diversified horticultural systems. Our analysis relies on a model of the effect of crop diversification on risk and expected yield. It is based on a dataset obtained from a range of 44 species and over a period of 10 years. Results show that (i) the variability of expected crop yield can be reduced up to 77% by choosing the appropriate crop combination; (ii) most common crop classifications such as botanical classification or functional types do not make it possible to identify suitable diversification strategies. These results provide insight into how different horticultural crop combinations may shape the relationship between production and risk in diversified farming systems. Our findings also provide indications on new diversification strategies based on a quantification of risk reduction.

Towards a better understanding of the today French torrents management policy through a historical perspective

Protective measures against torrential floods and lowlands’ floods have been set up since the 19th century in mountainous areas. To help decide on maintenance of numerous existing structures, a better understanding of their objectives and technical functions is needed. Nevertheless, that remains tricky in torrent management context, due to several changes for more than 150 years, either in terms of natural torrential risk (e.g. land-use changes), scientific understanding of complex phenomena (e.g. hillslope-streambed coupling), understanding of protective actions (e.g. influence on the sediment transport), laws and regulations (e.g. increasing of multi-issues problems), and management organization. An archive analysis was done to bridge this gap. Pioneering books of the late 19th century have been reviewed to sum up local and regional objectives of protective measures, but also their technical functions on torrential processes. We recall the first RTM laws and their implementation conditions. An analysis of laws, regulations and public management evolutions helps to understand risk management changes, influencing current maintenance decisions. We finally synthesize the objectives and local technical functions of protective measures. We propose some elements to go towards a quantification of risk reduction even if it remains a key challenge.