21. Enhancing Resilience of Food Production Systems Under Changing Climate and Soil Degradation in Semi-arid and Highlands of Tanzania

Soil resources play a central role in food security as agriculture continues to depend on soil to feed the growing population. The objective of this paper is to review the status of food security, extent of soil degradation, and management options under changing climate to ensure food security in the semi-arid and highlands areas of Tanzania. Increased food production was realized over a 10-year period in the country, attributed to the increase in cultivated land at the rate of 0.38 million ha/year. Food productivity decreased at the rate of 0.04 t/ha/year despite higher average food production after (18.00 t) than before (13.75 t) introduction of fertilizer subsidy. Soil degradation due to soil loss of 9.2 Mg/ha/season accounted for 24 % yield reduction in semi-arid areas, and soil loss was 32–163 kg/ha/year in highlands. Poor residue and tillage practices contribute to low productivity even when inputs are used. Nutrient mining is widespread with 88 % of soils deficient in nitrogen, 71 % with low phosphorus, 29 % are low in potassium, and 67 % are deficient in Zn in semi-arid areas. In highlands, 92 % of soils are deficient in phosphorus while 24 % are deficient in zinc. Almost all soils in semi-arid and 58 % of soils from highlands had low soil organic carbon. Salinity increased in almost all irrigated areas in semi-arid regions without salinity management. Thus, climate smart agriculture to simultaneously conserve soil, harvest and conserve rainwater, and integrate nutrient management should be used to increase productivity and enhance agriculture resilience to changing climate.