Abstract:
Food security will be the biggest challenge for Tanzania in the next decades. Besides, Tanzania has a multifarious ecosystem,
which is endangered through not adapted agronomic practices. Current innovation strategies focus mostly either on the issue of
food security or on environmental damages, but rarely on both issues. However, both issues are very crucial. With crop models,
a wide range of agricultural practices can be investigated to show possibilities to optimize the application of these practices.
Model assessments allow to separate the effects of agronomic and climatic conditions. The process-based model SWIM (Soil
and Water Integrated Model) can compute the impacts of agronomic practices and thus develop strategies to decrease the yield
gap between actual (farm) yields (Ya) and potential yields (Yp). The Yp are limited through the nutrient (Yn) and water supply
and reduced by pests, diseases, and weeds. Furthermore, socio-economic impacts are also relevant (knowledge, tradition, or
culture). These impacts can be captured by statistical crop models. Due to regional-adapted, integrated agronomic practices, Ya
can be increased and thus the yield gap between Ya and Yp can be decreased. However, enhanced yields due to sufficient
nutrient supply are more sensitive on climate (higher yield volatility). In particular, for innovative farmers increase the
production risk of climate change impacts. These endangered adaptation from farmers and therefore both food security and the
environment. However, not all influences between Ya and Yn can be explained by agronomic (fertilizer application, harvest
time, tillage, and plant protection) and climatic conditions. Additionally, the Ya are affected by a broad range of nonbiophysical,
socio economic constraints. To decrease the yield gap on regional level, agricultural practices and knowledge are
required, which consider regional-specific the issue of food security and environmental protection in a balanced ratio.
