Thesis (M.Dev.) --University of Limpopo, 2011 / Food security in most drought-stricken areas of Limpopo Province is a challenge to the Department of Agriculture and to all the people living in the province, especially to the resource poor smallholder farmers. Finding remedial solutions to agricultural production in stress prone conditions is therefore a high priority. The introduction of Challenge Programme Water for Food (CPWF) technologies/techniques to smallholder dry land farming in Greater Giyani Municipality was seen as one of the solutions. However, there are constraints raised by CPWF technology adopters such as shortage of labour, lack of ploughing equipment, lack of credit, shortage of land and marketing. CPWF technologies are suitable for smallholder dry land farming, especially rainwater harvesting technologies. Smallholder farmers need to be remobilised and trained on the potential benefits of CPWF technologies to enhance their adoption and spread to other areas.

As global temperatures rise, cultivation of C3 and C4 crops in arid and semi-arid regions will face major challenges in producing biomass for billions of people. Conventional agricultural techniques that require copious irrigation will need to be complemented with dryland-farming techniques and drought-tolerant crops, such as those from the Agave genus, which use CAM photosynthesis. In the past and present, humans from arid and semi-arid regions of America have maintained a symbiotic relationship using and cultivating Agave (Agavoideae, Asparagaceae). In pre-Columbian times, Native Americans from arid regions relied on Agave cultivation as a subsistence crop to produce food, medicine, and fiber. The Hohokam in the Sonoran Desert cultivated Agave plants using rock mulching, also known as rock piles. This technique enabled the Hohokam to extensively cultivate Agave despite the limited rainwater available in the harsh Sonoran Desert. Although there are several decades of archaeological research for documenting the history of rock piles and Agave in the region beginning in the late 1970s, few studies have addressed the modern application of rock piles to cultivate Agave. Our research employed a multidisciplinary approach to bridge the historic use of rock piles to cultivate Agave with the potential application of rock piles for modern cultivation. In addition to summarizing what is known about the archaeology of Hohokam rock piles, we compiled an extensive review of the literature available on the agroecology, physiology, and natural history of Agave. We described key aspects associated with the hydrology and physical properties of Hohokam rock piles that can bolster Agave CAM photosynthesis in dry regions. We found that the use of rock piles is a feasible means of cultivating Agave under hot and dry conditions in arid regions. In addition, we used an ecological niche modeling approach and field data from Hohokam rock-pile sites and current Agave fields to assess the potential environments where rock piles could be used to cultivate Agave plants in Arizona, USA and Sonora, Mexico. We also combined an experimental archaeology approach with experimental plant physiology where we surveyed Hohokam rock-pile fields at archaeological sites to collect information about the composition of rock piles. We then created a rock-pile field where we evaluated and observed the effects of rock piles on Agave CAM utilization, mainly nocturnal CO2 uptake of Agave. Our results indicated that rock piles provide direct insulation to root systems, which indirectly benefited Agave carbon uptake and reduced temperature and drought stress. Although more agronomic research about rock pile use is needed, our research suggests that rock piles can be applied to cultivate Agave because of the physiological benefits provided such as increasing nocturnal total CO2 uptake. In addition, the suitability of rock piles in the U.S borderlands indicates that rock piles can be applied beyond the regions where they were used by the Hohokam in pre-historic times.

The aim of this study was to evaluate risk management strategies and decision support tools that might be useful to dryland farmers in southwest Queensland to improve their decision making. This topic was chosen because there has been little previous work done to examine the sources of risk faced by farmers in that area, the practical risk management strategies employed by these farmers, or their interests in and attitudes towards risk management. This study adopted an action-learning approach to present farmers with opportunities to use various tools that might help to manage the range of risks affecting their farm management. The study was designed to test farmers’ interests in existing tools, or the potential for developing new tools, to assist dryland farmers in southwest Queensland improve their risk management. The thesis is presented in three parts including an introduction to the study and an extensive review of the relevant literature on decision making and risk management (Part I), an overview of the area in southwest Queensland where this study was focused and the various research methods used in this study (Part II). Part III comprises four chapters reporting results and presents the conclusions from the study. The thesis also reviews the advantages and disadvantages mentioned in the literature about decision support systems (DSS) in Australian agriculture and examines some programming and simulation models that can be applied to risk management in agriculture. The research methods used in this study included a literature review, interviews, focus group discussions, an ‘expert’ survey, training workshops for farmers, and evaluation techniques. The observations and reflections from the preliminary inquiries identified soil moisture management and crop choice as the critical issues concerning dryland farmers in southwest Queensland when dealing with crop production risks. Those discussions suggested possibilities for developing a decision support tool to help farmers in the study area assess their planting options. In developing the options for a decision support tool for planting decisions, a series of workshops was conducted with farmers in the study area, while some observations of farmers who attended similar workshops in adjacent areas are also reported. These workshops provided the opportunity for participants to experience some existing risk management and decision support tools. They were also designed to collect inputs to develop an appropriate decision support tool for crop planting decisions. A ‘Key to dryland planting decisions’ for farmers in southwest Queensland was developed and the personal experiences and lessons that the author has learnt through the course of this research are reported. The thesis enhances the understanding of farmers’ attitudes to risk, contemporary risk management strategies, and decision supports tools used in agriculture. This research has contributed to knowledge in the following ways. It has presented a methodological framework for doing research of this type. This study has identified the different sources of risk faced by dryland farmers in southwest Queensland and the practical risk management strategies they employ. The research has introduced those farmers to some existing risk management and decision support tools. The research has contributed more specifically to improving their management decisions by developing a decision support tool that could help dryland farmers in southwest Queensland make better informed and more appropriate planting decisions in the very uncertain and risky conditions with which they have to cope.