Around 30% of the world's population suffers from either a lack of one or more essential micronutrients, or the overconsumption of these minerals, which causes toxicity. Selenium (Se) is a particularly important micronutrient component of the diet with a well-documented and wide-ranging role in maintaining health. However, this important micronutrient can be lacking because soil and crop management are focused on high yields to the detriment of the quality of crops required to ensure a healthy human diet. Currently around 15% of the global population has selenium deficiency. This paper focuses on Se availability in semiarid soils and how micronutrients can be effectively managed through the recycling of organic matter. Because many mineral reserves are being exploited unsustainably, we review the advantages of using organic by-products for the management of the biofortification of Se in crops. This type of practice is particularly useful in arid and semiarid environments because organic matter acts as a reservoir for Se, preventing bioaccumulation and leaching. There are also potential local economic benefits from using organic by-products, such as manures and sewage sludge.

Much has been written about food security, nutrition security and the ability of people to access their food needs. Food sovereignty and the associated ability of people to participate in the production, distribution and consumption decisions of their food have been at the fringe of this discussion. Linked with this is the debate on the question of pursuing policies of food self-sufficiency or policies of self-reliance where food imports are considered a natural extension of food security. Examining the elements of food security through the food system participation framework of food sovereignty is an opportunity worthy of further exploration. This paper seeks to add a dimension to the understanding of food security by considering the value that a food sovereignty perspective has on the right to access food that is nutritious and safe for consumption. Current themes are cited and reviewed, and the implications of both food security and food sovereignty perspectives for the food system are argued. Agricultural trade liberalisation has benefited some societies and harmed others. To this end, the Global Strategic Framework (the Framework) on Food Security and Nutrition has recently incorporated the philosophy of the food sovereignty movement into its guidelines. The Framework provides an opportunity to view food security through a lens of food sovereignty providing guidance for all societies on how to safeguard their food security.

Concerns over the long-term sustainability of the food production system and the nutritional content of food from mineral depleted soils have encouraged a policy shift to sustainable agricultural practices where soil health supports nutrition-sensitive agriculture. Interventions at the micro scale have the ability to affect the entire system, forcing an examination at the whole of systems level. Modelling plays an important role in determining the outcomes of policy intervention combinations, particularly when systems are identified as being complex. This study begins with a systems map tracing the nutrient cycling process between natural ecosystem processes and farm practices from the bottom-up within a top-down framework. Soil is at the centre of this approach, expanding links to other influences within the framework in order to understand the relationships between elements in an environmental-agricultural system. Moving to a generic model from a broad conceptual system map is problematic when crop types, plant mineral absorption rates, soil and geographic differences are to be accommodated. Work has been done to develop top-down framework models integrating bottom-up component models, capable of being used in different scenarios. Whether existing models are used or new models are created, this study recommends that an appropriate modelling response require examination of systems and policy interventions both holistically and in detail encompassing situational specifics.

This paper presents a classification of agricultural production systems that we believe characterises the complex interface between agriculture and the landscapes in which they are managed. Farmers have a choice about how they will manage their land, either to exclude inherent environmental complexity or to engage with it, mindful of risks associated with their approach. Adding to this complexity is the interplay between key natural, social, human, physical and financial resources in agricultural systems, highlighting the importance of extending sustainability principles to aspects of ecology, economics and culture. Decisions about agricultural systems hinge on a balance of productive outcomes, on sensitivity to the issues of environmental complexity, on economic grounds including the access to resources, and the socio-cultural needs of the community in which the farmer participates. Further, farm managers will make a choice that both satisfies and suffices (satisfices) against production, ecological efficiencies and resilience outcomes when choosing which food production system to adopt. In this paper, these complexities are analysed against five different agricultural systems on an ecological continuum; from biologically simple industrial systems that minimise interaction with the natural environment, to ecologically complex systems that are closely engaged with their environment. Production viability is a necessary consideration to maintain farming operations but is not sufficient if operational capacity is to be achieved in the long term. This analysis finds that it is also necessary to work with ecological, economic and social complexities, satisficing against productivity, ecological efficiency and inherit system resilience. No one particular farming systems is appropriate in all cases. The farmer's choice may apply a mix of the five different agricultural systems described, allowing for the blending of these attributes in order to sustain rural landscapes.