The West Usambara Mountains are widely considered to be one of the most beautiful landscapes in eastern Tanzania, and have attracted people for thousands of years (the original Sambaa culture and more recently, colonial settlers and tourists). But below the surface of this beautiful and rugged landscape is a story of dramatically increasing population pressures on land and water resources, and, in the face of a changing climate, food insecurity.
The parched landscape of Lushoto before the beginning of the short rainy season. Near Mbuzii village, Lushoto District, TZ.
In intensively cropped, rugged landscapes such as the West Usambaras – where hand-tilled fields can exceed slopes of 35 degrees – gains made in crop productivity through improved access to fertilizer and seed varieties can easily be lost through erosion and poor soil management, which has long been recognized by farmers and researchers as a critical issue in the region.
Although well-developed indicators derived from local soil knowledge are useful for revealing qualitative differences, more quantitative information is needed to assess the effectiveness of different land management practices. Complementing local soil knowledge with quantitative information on soil fertility and erosion can provide data-driven approaches to best management practices if well integrated with socio-economic information and stakeholder participation – this integrative research is the major goal of the CGIAR Climate Change, Agriculture and Food Security (CCAFS) program in Tanzania.
Field erosion reveals strips of bedrock inbetween the remaining soil, which is planted with maize. Gare village, Lushoto District, TZ
In 2009, CCAFS established a benchmark site in Lushoto District, Tanzania, partnering with a diverse range of local, national, and international organizations*. Their objective was to gather baseline information at the household level about indicators of welfare; improving natural resource management strategies; assessing the needs and uses of climate and agricultural related information; and the implementation of climate-change mitigation and adaptation practices. This information is critical for prioritizing local, bottom-up interventions such as fertilizer and seed distributions, social programs and capacity building.
In 2012, CIAT conducted a biophysical field assessment of land and soil health in partnership with SARI and the Lushoto District Council using the Land Degradation Surveillance Framework (LDSF). The LDSF framework provides a scalable, standardized methodology to quantify and assess soil health across global agroecosystems. Products derived from LDSF data through the African Soil Information Service project (AfSIS) have resulted in the first highly detailed maps of soil properties throughout sub-Saharan Africa.
Supporting these efforts, Nic Jelinski, a visiting Ph.D. student and Borlaug Fellow supported by a Graduate Research Grant from Purdue University’s Center for Global Food Security, spent three weeks in Lushoto District gathering soil samples and data. His work included: sampling cultivated and natural ecosystems to attempt to quantify erosion rates through the natural abundance of radioisotopes, collecting geo-referenced land management information, and conducting informal workshops on soil morphology and description with district extension agents, partner NGOs and local farmers. This work will lead to improved soil information and knowledge, local capacity building, and future collaborations with Utrecht University, ARI-Mlingano, and Sokoine University of Agriculture.
Over the next 6 months, soil samples from Lushoto will be analyzed at the University of Minnesota, U.S.A. for naturally occurring radionuclides in order to quantify erosion rates across different land-uses and management practices throughout the CCAFS landscape. The results will be disseminated to CCAFS extension agents in Lushoto to assist and adapt current advising practices. Descriptive soils information will be distributed by CCAFS extension agents to villages and individual farmers who granted access to their properties for the purposes of sampling. Follow-on projects will include setting up long-term monitoring and further refining the relationship between best management practices and decreases in soil erosion.
Targeted initiatives, including those led by CCAFS through CIAT, have a major opportunity to contribute to a better future in Lushoto. Ensuring food security for an entire landscape, a growing population, and a unique culture depends on the effective management of soil resources.
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Written by Nic Jelinski.
Photographs: Nic Jelinski
Nic is a PhD student from University of Minnesota-Twin Cities supported by a Graduate Research Grant from Purdue University’s Borlaug Center for Global Food Security. Nic is working with Dr. Leigh Winowiecki (Soil Scientist, CIAT) to link descriptive soils information and estimates of erosion severity derived from radionuclides to large-scale mapping and data collection by the World Agroforestry Center (ICRAF) and CIAT.
*CCAFS Partners in Lushoto: the Selian Agricultural Research Institute (SARI), Tanzania Forestry Research Institute (TAFORI), Sokoine University Of Agriculture (SUA), Lushoto District Council and Department of Agriculture /Livestock and Cooperatives, African Highland Initiative (AHI); International Livestock Research Institute (ILRI); and the International Centre For Potatoes (CIP).
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