MAY 2017 Can Tanzania feed itself by 2050? Estimating cereal self-sufficiency to 2050 Joachim H.J.R. Makoi National Irrigation Commission of Tanzania Martin K. van Ittersum1 Wageningen University & Research Keith Wiebe International Food Policy Research Institute RESE ARCH SUMMARY P roducing adequate food to meet global demand by 2050 is widely recognized as a major challenge, particularly for Africa south of the Sahara, including Tanzania (Godfray et al. 2010; Alexandratos and Bruinsma 2012; van Ittersum et al. 2016). Increased price volatility of major food crops (Koning et al. 2008; Lagi et al. 2011) and an abrupt surge in land area devoted to crop production in recent years (Grassini et al. 2013) reflect the powerful forces underpinning this challenge. The 2008 price spikes triggered the Food and Agriculture Organization and the World Food Programme to issue warnings and call for a 60–70 percent increase in food production by 2050 to meet the escalating food demand for the expected 9.7 billion global population. A number of studies argue that it is possible to meet projected global food demand using existing agricultural land by narrowing gaps between actual farm yields and yield potential (Koning et al. 2008; Tilman et al. 2011; Foley et al. 2011; Mueller et al. 2012; Mauser et al. 2015; Pradhan et al. 2015; Erb et al. 2016). Although meeting the increased global demand may be possible, a more pressing question is whether and how different regions of the world can meet their respective demands for staple food crops. More specifically, although Africa’s current self-sufficiency ratio in staple cereals is just above 0.8 (Figure 1), it is among the regions with the lowest cereal self-sufficiency ratio, while it faces the greatest projected increase in population (UN 2015; Sulser et al. 2015). Self-sufficiency is defined here as the ratio between domestic production and total consumption (or demand); the latter is assumed to be equal to domestic production plus net imports. While recognizing that food self-sufficiency is not an essential precondition for food security, self-sufficiency for low-income developing countries is of great concern because many lack adequate foreign exchange reserves to pay for food imports and the infrastructure needed to store and distribute food efficiently. Cereals make up about 50 percent of Africans’ caloric intake and account for about 50 percent of the cropland area in Africa south of the Sahara. In this policy brief, future self-sufficiency for five main cereals—maize, sorghum, millet, wheat, and rice—is reported for Tanzania. These five crops make up 44 percent of the crop area in Tanzania. The reported findings are based on a recent publication in the Proceedings of the National Academy of Sciences of the United States of America (van Ittersum et al. 2016), and all methods are described in that paper. 1 Martin K. van Ittersum is the corresponding author (martin.vanittersum@wur.nl). mailto:martin.vanittersum%40wur.nl?subject= Current cereal self-sufficiency and trends in Tanzania Tanzania’s current cereal self-sufficiency is estimated at 0.76 (or 76 percent), using 2010 as the reference year. Future cereal self-sufficiency in Tanzania will depend on the increase in national population, dietary changes, yield increases, and area expansion. The current national population is 45 million (UN 2015). Population scenarios for 2050, developed by the United Nations, project 124 million, 137 million, and 151 million people for low-, mid-, and high-fertility scenarios, respectively. In other words, the population is expected to approximately triple by 2050. Because of anticipated income growth and associated dietary changes, cereal demand in 2050 is expected to increase by a factor of 3.8 relative to 2010. Tanzania’s average actual maize yield (2003–2012) was 1.2 tons per harvested hectare, according to national statistics. The so-called water-limited yield potential for maize was 5.4 tons per harvested hectare. Water-limited yield potential assumes unconstrained crop growth under rainfed conditions and perfect management that avoids limitations from nutrient deficiencies and reductions from weeds, pests, and diseases. In regions of the world with highly productive agriculture, yields can reach 80 percent of the water-limited yield potential; further yield increases are typically not beneficial from an economic point of view nor desirable from an environmental perspective. Future cereal self-sufficiency in Tanzania Self-sufficiency ratios by 2050 were estimated for various yield-increase scenarios for Tanzania. Based on 2010 actual yields, and assuming no yield changes or area changes until 2050, the self-sufficiency ratio is estimated as 0.20 (0.22, 0.18) in the mid (low, high, respectively) population projections. Extrapolating the average yield increases observed between 1991 and 2014 to 2050, the self-sufficiency ratio is 0.25 (0.27, 0.22) in mid (low, high) population projections. However, if yields are raised to 50 percent of their water-limited potential, the self-sufficiency ratio reaches 0.45 (0.50, 0.41) in mid (low, high) population projections. Likewise, if farmers raise yields to 80 percent of their water-limited potential by 2050, self-sufficiency ratios reach 0.72 (0.79, 0.65) in mid (low, high) population projections. This suggests that yield gaps must be almost fully closed by 2050 to retain today’s self-sufficiency levels in Tanzania’s five main cereals. For instance, an increase in maize yields from the 2010 yield (1.2 tons/ha) to 80 percent of the water-limited potential (4.3 tons/ha) implies an annual yield increase of 78 kg/ha, a rate of increase that is high in comparison with historical changes (in fact, actual average maize yields did not increase significantly from 1991–2014). Figure 1 Self-sufficiency ratios by 2050, based on various yield-increase scenarios Source: van Ittersum et al. 2016. Note: Yield scenarios are as follows: 2010 actual farmers’ yields (Ya); actual yield increase 1991–2014 extrapolated to 2050 (Ya extrapolated); yield increased to 50% or 80% of water-limited potential (Yw). Ratios for the 10 countries by 2050, assuming current cereal areas (no expansion). 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 Self-sufficiency ratios Burkina Faso Ghana Mali Niger Nigeria Ethiopia Kenya Tanzania Uganda Zambia Yield gaps closed to 80% of Yw Yield gaps closed to 50% of Yw Actual yield increase 1991–2014 extrapolated to 2050 (Ya extrapolated) Actual farmers yields 2010 (Ya) Required yield and crop area increases in Tanzania Current area under the five cereals in Tanzania accounts for 44 percent (5.2 million hectares [Mha]) of total cropped land (11.9 Mha). Between 2004 and 2013, cropland area increased by 4.0 Mha. Given the current cereal area of 5.2 Mha and the potentially suitable cereal area of 15.2 Mha, the area required to achieve cereal self-sufficiency of 1 by 2050 will be 26.2 Mha for the yield scenario based on the 2010 actual farmers’ yield, and 21.2 Mha based on an extrapolation of 1991–2014 actual yield increases. However, because of the shortage of suitable land, neither scenario is possible. If yields are raised to 50 percent of their water-limited potential, the cereal area required is 11.6 Mha. Similarly, if yields are increased to 80 percent of their water-limited potential, the cereal area required is 7.3 Mha. Hence, in addition to the large annual yield increases (78 kg/ ha), an expansion of about 40 percent in cereal area is needed to reach cereal self-sufficiency of 1 by 2050. Such expansion would come with substantial greenhouse gas emissions and biodiversity losses. Implications for current development policy Current government policy aims to move Tanzania toward middle-income-country status through industrialization. Agricultural and industrial production are interdependent—agricultural production will provide food, labor, money, raw materials, and many other benefits essential to industrialization. Achieving a greater degree of self-sufficiency in food production by closing yield gaps will be important for Tanzania to realize its development goals. The study reveals the enormous challenge of keeping up with anticipated increases in future cereal demand. Full yield gap closure on existing cereal land is needed to roughly maintain today’s self- sufficiency. Closing the yield gaps implies an enormous break from observed historic trends in annual yield increases. It requires use of improved cultivars, hybrids, and seed, coupled with increased use of fertilizers, modern pest management practices, and good agronomy. With these changes, accelerated rates of yield gain are possible (Abate et al. 2015; Sanchez 2015). However, accelerated intensification will require greater investment in research and development (R&D) in both public and private sectors. This investment is needed now, and will be even more urgent under future climate change. Investments in agricultural R&D must be matched by supportive policies and public finance for improved transport and communication, market infrastructure, credit, insurance, and improved land entitlements. In the study’s calculations, rainfed cereal production is the dominant form of production. Tanzania’s government may also opt to invest in irrigation (that is, climate resilient infrastructure), which would lead to higher potential yields and more scope for production increases. Further, an increase in intensity of cropping systems (growing more than one crop per 12 months) may help Tanzania keep up with the future increase in demand (van Ittersum et al. 2016). Acknowledgments This note is based on research performed in the context of the Global Yield Gap Atlas (GYGA) project (www.yieldgap.org) and supported by the Bill & Melinda Gates Foundation, the Robert B. 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