Post-Disaster Food and Nutrition from Urban Agriculture: A Self-Sufficiency Analysis of Nerima Ward, Tokyo

Abstract

Background: Post-earthquake studies from around the world have reported that survivors relying on emergency food for prolonged periods of time experienced several dietary related health problems. The present study aimed to quantify the potential nutrient production of urban agricultural vegetables and the resulting nutritional self-sufficiency throughout the year for mitigating post-disaster situations. Methods: We estimated the vegetable production of urban agriculture throughout the year. Two methods were developed to capture the production from professional and hobby farms: Method I utilized secondary governmental data on agricultural production from professional farms, and Method II was based on a supplementary spatial analysis to estimate the production from hobby farms. Next, the weight of produced vegetables [t] was converted into nutrients [kg]. Furthermore, the self-sufficiency by nutrient and time of year was estimated by incorporating the reference consumption of vegetables [kg], recommended dietary allowance of nutrients per capita [mg], and population statistics. The research was conducted in Nerima, the second most populous ward of Tokyo's 23 special wards. Self-sufficiency rates were calculated with the registered residents. Results: The estimated total vegetable production of 5660 tons was equivalent to a weight-based self-sufficiency rate of 6.18%. The average nutritional self-sufficiencies of Methods I and II were 2.48% and 0.38%, respectively, resulting in an aggregated average of 2.86%. Fluctuations throughout the year were observed according to the harvest seasons of the available crops. Vitamin K (6.15%) had the highest self-sufficiency of selected nutrients, while calcium had the lowest (0.96%). Conclusions: This study suggests that depending on the time of year, urban agriculture has the potential to contribute nutrients to diets during post-disaster situations as disaster preparedness food. Emergency responses should be targeted according to the time of year the disaster takes place to meet nutrient requirements in periods of low self-sufficiency and prevent gastrointestinal symptoms and cardiovascular diseases among survivors.

Keywords: disaster; emergency; nutrition; preparedness; public health; self-sufficiency; urban agriculture; vegetable.

Conflict of interest statement

Giles Bruno Sioen received support by The Ministry of Education, Culture, Sports, Science and Technology from the Japanese Government (Monbukagakusho: MEXT) Scholarship. The Graduate Program in Sustainability Science—Global Leadership Initiative and The School of Frontier Sciences, both from The University of Tokyo, provided the software and other resources to conduct this research. The land use planning section of Tokyo Metropolitan Government (application number: 29022) provided the spatial data. The sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

Figures

Figure 1

Flowchart of analysis.

Figure 2

Planting and harvesting schedule by vegetable and season [34]. Each month was divided in three time periods (beginning, middle, and end). J.M. spinach: Japanese mustard spinach. Legend: 0 = No activity; 1 = Seeding; 2 = Planting; 3 = Growing; 4 = Harvesting.

Figure 3

Tokyo’s 23 special wards where UA can be found (Nerima ward bolded) [33].

Figure 4

Urban agriculture in Nerima ward, Tokyo. Hobby UA consist of both allotment and experience UA. Basemap: Tokyo Metropolitan Government [22,31].

Figure 5

Self-sufficiency in Nerima ward from professional UA (Method I).

Figure 6

Self-sufficiency in Nerima ward from hobby UA (Method II).

Figure 7

Aggregated self-sufficiency in Nerima ward from professional and hobby UA (Method I and II).

Figure 8

Vulnerable wards with high-densities of Moku-chin (characterized by narrow roads, causing greater risks in emergency situations [53]) in the 23 special wards of Tokyo (Nerima ward bolded) [33].

Figure 9

Disaster drill held in Nerima ward. (a) Urban farmland with a high diversity in crops; (b) Farmer and volunteers preparing soup with fresh vegetables from the farm in a portable gas stove; (c) Rice and crackers provided by the municipality as emergency food with freshly made soup containing vegetables from the farm; (d) People from the neighborhood familiarizing with each other and the farmer (photographs by the authors, November 2016).