Retrospective Predictions of Rice and Other Crop Production in Madagascar Using Soil Moisture and an NDVI-Based Calendar from 2010–2017

Angela J Rigden,Peter Huybers,Christopher Golden

doi:10.3390/rs14051223

Angela J Rigden, Peter Huybers + Show 1 more

Open Access

https://doi.org/10.3390/rs14051223

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Journal: Remote sensing	Publication Date: Mar 2, 2022
Citations: 7	License type: CC BY 4.0

Affiliation: Harvard University, Planetary Science Institute

Abstract

Malagasy subsistence farmers, who comprise 70% of the nearly 26 million people in Madagascar, often face food insecurity because of unreliable food production systems and adverse crop conditions. The 2020–2021 drought in Madagascar, in particular, is associated with an exceptional food crisis, yet we are unaware of peer-reviewed studies that quantitatively link variations in weather and climate to agricultural outcomes for staple crops in Madagascar. In this study, we use historical data to empirically assess the relationship between soil moisture and food production. Specifically, we focus on major staple crops that form the foundation of Malagasy food systems and nutrition, including rice, which accounts for 46% of the average Malagasy caloric intake, as well as cassava, maize, and sweet potato. Available data associated with survey-based crop statistics constrain our analysis to 2010–2017 across four clusters of Malagasy districts. Strong correlations are observed between remotely sensed soil moisture and rice production, ranging between 0.67 to 0.95 depending on the cluster and choice of crop calendar. Predictions are shown to be statistically significant at the 90% confidence level using bootstrapping techniques, as well as through an out-of-sample prediction framework. Soil moisture also shows skill in predicting cassava, maize, and sweet potato production, but only when the months most vulnerable to water stress are isolated. Additional analyses using more survey data, as well as potentially more-refined crop maps and calendars, will be useful for validating and improving soil-moisture-based predictions of yield.

Highlights

Madagascar has one of the highest rates of poverty in Africa, with 42% of the country’s children under five experiencing chronic malnutrition and stunting [1]
Because the applicability of existing crop calendars are unclear for the crops we evaluate in Madagascar, we develop and apply a crop calendar based upon the normalized difference vegetation index (NDVI)
Cassava, and maize, though, we find no correspondence between variations in sweet potato production and Soil moisture anomalies using C3 (SMC3) in any region, the national-level r-value is 0.68

Summary

Introduction

Madagascar has one of the highest rates of poverty in Africa, with 42% of the country’s children under five experiencing chronic malnutrition and stunting [1]. Smallholders, are extremely vulnerable to disruptions in production due to their high dependence on agriculture for livelihoods, low rate of imports, chronic food insecurity, poor infrastructure, and lack of social safety nets [3–5]. Understanding how variations in weather affect agricultural production is useful when developing climate adaptation strategies, such as the selection of crops and varieties as well as management of water resources [2,3]. Empirical studies underscore that increasing agricultural production in Madagascar is an important strategy to reduce poverty and food insecurity rates in rural regions [10], where most of the population resides (61% in 2020) [11].

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