1. Introduction
Among the great challenges the world faces is how to feed a growing global population. That is why in September 2015, at the Sustainable Development Summit, the world leaders adopted the 2030 Agenda for Sustainable Development, which includes 17 Sustainable Development Goals (SDGs). “Ending hunger, achieving food security and improving food nutrition, and promoting sustainable agriculture” are the major points, amongst others of the second SDGs (
https://www.un.org/development/desa/disabilities/envision2030-goal2.html). Therefore, this study, using the framework of the SDGs, attempts to answer the urgent call on how to boost agricultural productivity, taking Comoros as a case study of a food-deficient country. Approximately 71% of the food-deficient countries are located in Africa, where many studies have highlighted the phosphorus deficiency of the soil in general and in sub-Saharan Africa in particular [
1,
2,
3,
4,
5,
6]. However, there is currently a dearth of clear and specific estimates of the phosphorus requirements for overcoming this deficiency and boosting the agricultural productivity of a single nation. Thus, this article attempts to estimate the phosphorus requirements for Comoros to satisfy its food needs solely by domestic food production. Considering its rapid population growth, how many tons of food and phosphorus will be required to feed the growing number of Comorian mouths at the national level, in 2030?
Phosphorus is one of the three essential nutrients that plants need for growth, and there is no substitute for it. Phosphorus is obtained from phosphate rock and is applied as fertilizer on agricultural soil. It plays an important role in food production and has been used for increasing crop yields for quite a long time (probably since the 1950s) [
4,
7,
8,
9]; 90% of the global phosphorus demand is for food production [
10] and approximately 170.7 million tons of phosphorus fertilizer nutrients were consumed in 2010, worldwide [
11]. However, phosphorus consumption varies from one country to another, despite its crucial role in growing plants. In general, Africa is the continent with the lowest phosphorus fertilizer consumption in the world [
4,
12], although the largest phosphate reserves (approximately 85% of the world’s share) are found in an African country (Morocco: Estimation data from the International Fertilizer Development Center (IFDC) reserves for products). Comoros is among those African countries with little or no phosphorus fertilizer application to agricultural soils.
Agriculture is the most important economic sector in Comoros. It contributes 40% of the Gross Domestic Product (GDP) and 90% of fiscal revenues, and employs over 80% of the population [
13,
14,
15]. It provides an essential proportion of basic food needs for consumption. Yet despite the importance of phosphorus, Comorian agriculture is dominated by small-scale farmers using rudimentary practices, including little or no phosphorus fertilizer input [
16]. Consequently, domestic food crop production per capita has decreased during the last two decades [
17]; nearly 95% of the rice consumed in Comoros is imported [
18] and currently rice production in Comoros has now essentially ceased. Therefore, to satisfy the population’s needs, the country imports almost 40% of its total food requirements [
19], from cereals to livestock products, to sugar crops, to vegetables. Currently, the situation is exacerbated by the rapid rate of population growth, and the country relies on imports to feed its population [
20]. One of the difficulties of becoming a net food importer—an import-dependent nation—is that Comoros is one of the world’s poorest countries, near the bottom of the low-income countries (ranked 174 of 182 countries according to the 2017 World Bank data) (
www.https://en.wikipedia.org/wiki/List_of_countries_by_GDP_(PPP)_per_capita). Hence it has serious difficulty paying the import food bills solely from the revenue derived from its three main agricultural exports (vanilla, cloves, and ylang-ylang) [
21]. Thus, there is an urgent need to estimate the phosphorus requirements for Comoros, in order to boost sustainable agricultural productivity and increase crop yields.
In order to introduce sufficient innovations to the agricultural sector to achieve a 100% food Self-Sufficiency Ratio (SSR) and become a food import-independent nation, the Comorian government has implemented initiatives and set up long-term goals, by upgrading its Strategy for Accelerated Growth and Sustainable Development plan to the SCA2D-2030 for an emerging country. This process will require an intensification of agricultural inputs, especially phosphate fertilizer. Therefore, to understand how the agricultural sector could grow faster in terms of sustainable productivity improvement, it is necessary to estimate the phosphorus volume Comoros requires to achieve 100% SSR and meet its future domestic food demand.
The purpose of this study was therefore to estimate the phosphorus requirements for the Comorian agricultural sector to feed the future population. This goal comprises three main tasks: (1) an analysis and estimation of the embedded and virtual phosphorus flowing through the food trade in Comoros, from 1991 to 2013; (2) an empirical assessment of the current SSR based on food production in Comoros for selected items; and (3) an analysis of demand projections for food items and phosphorus requirement under two scenarios: Scenario 1, reach 90% of the SSR, and Scenario 2, achieve 100% of the SSR, by 2030.
2. Materials and Methods
2.1. Description of the Study Area
Comoros is an archipelago country, made up of four islands: Grande Comore (1146 km
2), Anjouan (424 km
2), Moheli (290 km
2), and Mayotte (374 km
2), located at the entry of the Mozambique Channel in the western Indian Ocean between the east coast of Africa and the northern cost of Madagascar. One island, known as Mayotte, remained under French administration and was claimed by Comoros in 1975 with the support of the United Nations. Therefore, our study was confined to the three islands within the administrative boundaries of Comoros
Figure 1. The country is among the poorest in the world, with a Gross Domestic Product (GDP) of US
$835 per capita, and an estimated population of 870,000 inhabitants (
https://data.worldbank.org) in 2013.
Agriculture is the main sector of the Comorian economy, contributing nearly 90% of the national export earnings [
22]. Export income, however, is reliant on the three main cash crops: vanilla, cloves, and ylang-ylang. Thus, despite the importance of agriculture, food demand in Comoros is not met by domestic production, forcing the country to rely on imported foods to satisfy the national needs, and Comoros has become a net food importer, an import-dependent nation. This food import reliance is expected to increase along with population growth, unless domestic food production improves.
2.2. Phosphorus Flows from Imported and Exported Commodities in Comoros
2.2.1. Virtual Phosphorus Flows from Imported Commodities in Comoros
Here, virtual phosphorus, as the term implies, refers to simply the amount of mineral phosphorus fertilizer used in other countries to produce the commodities (food and livestock) that are imported into Comoros. The idea is taken from the similar terms ‘virtual water’ [
23] and ‘virtual nitrogen’ [
24], and has been used by many scientists [
25,
26,
27]. We calculated the virtual phosphorus based only on imported commodities. The virtual phosphorus attributable to exported commodities was considered to be equal to zero in this study, because all the Comorian export commodities are produced without mineral phosphorus fertilizer application, and data on uptake phosphorus from natural sources were difficult to obtain. Hence, we estimated the virtual phosphorus for Comoros using the following equation [
27]:
where
Qi,j corresponds to the volume of the product that was imported into Comoros (where
i = 1, 2, …,
n are the different types of commodities from countries
j, 1, 2, …,
m that the commodities came from);
corresponds to the coefficient of conversion from raw commodities into processed products;
yield corresponds to the yield of product
i in country
j; and
fertilizer corresponds to the amount of mineral phosphorus fertilizer applied to crop
i to produce food
j.
2.2.2. Embedded Phosphorus Flows through Imported and Exported Commodities in Comoros
Here, embedded phosphorus refers to the sum of the amount of phosphorus contained (physically embedded) in each imported crop and livestock product. We calculated it for the main Comorian imported and exported commodities, by multiplying the amount of the commodity traded by the corresponding phosphorus contained in each commodity (See
Supplentary Materials, Table S1).
2.3. SSR in Food Production for the Selected Items and Scenarios Anlaysis
The Food and Agricultural Organization of the United Nations (FAO) defines SSR as the percentage of food consumed that is produced domestically [
28]. It is estimated in either calories or in volume of food produced. It can also be expressed as the monetary value of the food, or measured in terms of specific commodities. It is an index that indicates how effectively domestic food consumption is covered by domestic production. We selected items that are main staple foods annually imported into the country (See
Supplentary Materials, From Tables S2 to S11). The SSR (based on food production) in the selected food items in Comoros was calculated using the following equation [
29]:
where
Pi is production,
Ii is imports,
Ei is exports, and ∆
Ri is stocks (or change in reserves) for a country
i. ∆
Ri was considered to be equal to zero in this study, because there were no stocks; the total annual food produced domestically was consumed domestically.
We calculated the mineral phosphorus requirement in 2030 under two scenarios: scenario 1, if the country wants to reach 90% of the SSR, and scenario 2, if it wants to achieve 100% of the SSR.
2.4. Projections of Food Demand
The main determinants of food demand are population size, price, income, and population preferences. Demographic changes also have an impact on food demand. Food demand is estimated on the basis of assumptions about the base year demand, economic growth, population, and expenditure elasticity. We first analyzed the current and future (in 2030) food demand in Comoros.
The population of Comoros is estimated to have been 813,000 inhabitants in 2018 (UN estimation), with an annual population growth of 2.4% (see
Supplentary Materials, Figure S1). Comoros has a rapidly increasing population and is expected to reach 1,062,000 in 2030 (UN estimation:
https://population.un.org). It is among the fastest growing populations in Africa, with a population density of 309.3 per square kilometer and about 71% of the Comorian population resides in the rural areas and relies on agriculture for livelihood [
30,
31].
On the economic side, the Comorian economy has not performed well during the last few decades. However, economic growth has improved recently (see
Supplentary Materials, Figure S2). Annual real GDP growth rose from −5.4% in 1991 to 2.8% in 2018, and is expected to reach 7.5% in 2030. The food commodities demand was projected for the year 2030 based on 2013 prices (see
Supplentary Materials, Tables S12 and S13), and we assume that the economy and population of Comoros will grow at the rate of 7.5% and 1,062,000 inhabitants in 2030, respectively. Hence, the projected food-item demands were calculated using the following equation:
where
Dt is the household demand for commodities in year
t;
d0 is the per capita demand for the commodities in the base year;
y is the growth in per capita income;
e is the expenditure elasticity of demand for the commodity; and
Nt is the projected population in year
t.
Finally, we quantified the phosphorus that will be required for future food production in Comoros, using the conversion factor [
32], which estimates the phosphorus required to produce one kilogram of food crops or one kilogram of livestock products:
For food crops, we calculated the phosphorus using the following equation:
For animal products, we calculated the phosphorus using the following equation:
2.5. Data Collection and Sources
Because statistical data in Comoros are hard to get, we mainly collected our data from various national and international sources, such as the International Monetary Fund (IMF: statically appendix, (1997); (2004); (2006); (2009)), the Central bank of Comoros (BCC: annual reports, trade statistics data, (from 2005 to 2013), (FAOSTAT: from 1991 to 2013)), and the existing literature (see
Supplementary Data and Materials).
2.6. Uncertainty Analysis
It is important to note that there is no doubt that our findings contain some uncertainties because our data were taken from multiple sources and were incomplete. First, some uncertainties are associated with the origin of the data. For example, our data were from several different institutions, and sometimes data varied from one institution to another, even in the same time period, so we had to adjust and reconcile the differences. Finally, it is likely that food aid is not reported to the database, although Comoros always gets some form of food aid, from Japan (rice) and Saudi Arabia (red meat), which could increase the volume of imported foods. Nevertheless, these uncertainties represent a small part of the phosphorus requirements in Comoros. Therefore, our data can be used credibly.
4. Conclusions
In this study, we estimated the phosphorus fertilizer requirements for the future food demand in Comoros. First, we calculated the phosphorus flows through food trade in Comoros, over 22 years, from 1991 to 2013. Secondly, our SSR results show that Comoros has an average SSR far below 100% and is not able to easily afford adequate food imports, or to distribute them equally, ensuring food security for all. Finally, the study found that approximately 3,337,150.10 kg of phosphorus fertilizer will be required by Comoros in 2030, to boost the domestic food production and considerably diminish the food imports. For a country like Comoros, where the domestic agricultural sector is struggling to provide enough food for its population, the efficient application of these amounts of phosphorus could help reduce the burden of the food import bill and minimize the food-import dependency by allowing farmers to improve their food productivity, which in turn will increase their livelihoods and ensure an adequate daily diet. This study is the first to quantify the phosphorus that will be required for Comoros to achieve these long-term goals. These precise and accurate estimates of phosphorus requirements could be used in the Accelerated Growth and Sustainable Development Strategy (SCA2D-2030) plan adopted by the Comorian government. It is important that Comoros considers ways to obtain the amount of phosphorus it needs, to ensure food self-reliance for its future population.
The agricultural sector in most food-deficient countries significantly contributes to the food consumption. However, with little or no P fertilizer application, the agricultural output stagnates, and domestic food production becomes less and less able to satisfy the population’s needs. Consequently, most food-deficient countries become food import-dependent nations, and are likely to experience an imbalance in food trade. To counteract this trend, appropriate agricultural policies in food-deficient countries can play a crucial role in boosting economic development through agricultural production, as has happened in developed countries. This goal will only be achieved, however, if agricultural policies, resource use, and agricultural production are well-developed and efficiently implemented, and food needs and production are regularly monitored. Phosphorus presents a unique opportunity for increasing crop yields and should be utilized, in order to reach the goal of zero hunger by 2030.
This study, based on empirical evidence, has shown that it would better for food-deficient countries to import enough phosphorus fertilizer to allow them to replenish their agricultural soil and produce sufficient foods to satisfy the national needs and achieve 100% SSR.