OBJECTIVES

The general objectives of this project are the domestication of indigenous fruit trees by means of sustainable techniques and the study of their effect on soil to avoid degradation.

Measurable, specific objectives are:

• to assess the ecological and physiological requirements of promising indigenous species;
• to assess the nutritional value of the fruits or their derivatives;
• to assess the efficiency of the root system in exploiting soil resources;
• to assess the dependence on mycorrhizal symbiosis for growth and drought tolerance;
• to evaluate appropriate agronomic practices;
• to assess the efficacy and limits of locally available organic fertilisers, like seaweed;
• to evaluate the effect of the cultivation on the physical and chemical characteristics of the soils.

ACTIVITIES

• Selection of promising phenotypes of Sclerocarya birrea, Strychnos spp., Ricinodendron rautanenii, Vangueria infausta, Azanza garkeana and Grewia flava.
• Pedologic assessment of naturally productive fields in Botswana and Namibia; chemical, physical and mineralogical analysis of soils; investigation of wild trees (root growth, contents of mineral elements in roots and above-ground compartments, soil nutrient availability); nutritional and chemical analysis of fruits or their derivatives.
• Study of the effect of the plants on the reduction of soil degradation by pot and field trials.
• Evaluation of the effects of growth limiting factors (nutrient availability, water stress, mechanical impedance) on root and shoot growth; effects of mycorrhizae in amelioration of stress effects.
• Evaluation of the efficiency of mycorrhized versus not mycorrhized plants in greenhouse and in the field. Distinguishing between different mycorrhizal associations by molecular methods; evaluation of the efficiency of different mycorrhizal fungi in relation to non mycorrhized seedlings (climate chambers and greenhouse).
• Preliminary planting trials and assessment of the efficacy of agronomic practices for a better rainwater management. Tests of natural fertilisers and growing stimulators (seaweed extracts) in pots and in the field.

EXPECTED OUTCOME

The work will enhance our understanding of the conditions determining plant success at different sites in semi-arid environments. Particularly important will be any information on practises regarding seeds, seedlings and planting techniques. The assessment of the relationships between mycorrhized roots and soil properties will contribute to the development of ways of avoiding erosion and land degradation. The results of such research could confirm indigenous fruit trees as an alternative and integrated farming system that reduces dependence on arable agriculture and enhances the quality of life of rural people.