Impact of improved maize varieties on food security in Eastern Zambia: A doubly robust analysis

• Date: 01 November 2018
• Author: Julius Manda,Arega D. Alene,Cornelis Gardebroek,Elias Kuntashula
• DOI: http://doi.org/10.1111/rode.12516
• Published date: 01 November 2018

REGULAR ARTICLE

Impact of improved maize varieties on food

security in Eastern Zambia: A doubly robust

analysis

Julius Manda

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Cornelis Gardebroek

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Elias Kuntashula

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Arega D. Alene

1

1

International Institute of Tropical

Agriculture (IITA), Lilongwe, Malawi

2

Wageningen University, Wageningen,

The Netherlands

3

University of Zambia, Lusaka, Zambia

Correspondence

Julius Manda, International Institute of

Tropical Agriculture, P.O. Box 30528,

Lilongwe, Malawi.

Email: j.manda@cgiar.org

Funding information

The authors gratefully acknowledge

financial support from USAID/Zambia.

The funding for the study was received

through a project called “Sustainable

Intensification of Maize–Legume Systems

for the Eastern Province of Zambia

(SIMLEZA)”.

Abstract

This study investigates the impact of improved maize

varieties on household food security in eastern Zambia

using household survey data from a sample of over 800

rural households. Since treatment effect estimates are

often prone to misspecification in either the treatment or

outcome equation, we use the doubly robust inverse prob-

ability weighted regression adjustment method, comple-

mented with propensity score matching on six different

food security measures to obtain reliable impact esti-

mates. Generally, we find a positive impact of improved

maize adoption on food security across the two econo-

metric approaches. Maize being the most important food

staple in Zambia has a great bearing on the food security

status of farm households. It is therefore imperative that a

conducive environment is created that promotes the adop-

tion of maize yield improving technologies.

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INTRODUCTION

Sustainable agricultural production is important in reducing poverty and food insecurity in Sub-

Saharan African countries. With rapidly rising populations and often slow growth in agricultural

productivity, most African countries are exposed to recurrent food emergencies and the uncertain-

ties of food aid; hence, increasing and stabilizing domestic production of food staples is essential

for food security (World Bank, 2007). Although agricultural production has improved, climate

change, environmental degradation, limited adoption of improved agricultural technologies, and

global food price volatility threaten the improvements gained, maintaining food insecurity in Africa

(World Bank, 2007).

DOI: 10.1111/rode.12516

Rev Dev Econ. 2018;22:1709–1728. wileyonlinelibrary.com/journal/rode ©2018 John Wiley & Sons Ltd

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In Zambia, agriculture is a priority sector in achieving sustainable economic growth and reduc-

ing poverty and food insecurity. The sector supports the livelihoods of over 70 percent of the pop-

ulation and contributes about 15 percent to the national gross domestic product (Kalinda, Tembo,

& Kuntashula, 2014; Sitko et al., 2011). Maize is Zambia’s principal food staple, accounting for

about 60 percent of national calorie consumption and serving as the dietary mainstay in central,

southern, and eastern Zambia (Dorosh, Dradri, & Haggblade, 2009). Its primacy has grow n stea-

dily as the result of past government policies that have encouraged the production of maize in all

parts of the country (Kumar, 1994). In some cases, farmers sell surplus maize and according to

Jayne et al. (2010), maize is the single most important crop in smallholder farm income with gross

income of about 41 percent attributed to it. The majority of the maize is produced by smallholder

farmers in rural areas who make up about 80 percent of the entire maize production in Zambia

(Sitko et al., 2011).

According to Kalinda et al. (2014), increasing maize productivity and incomes of smallholders,

both of which have remained very low, is a major challenge facing Zambia. Improving the produc-

tivity and production of maize through generation and development of improved maize varieties

could be an important approach to achieve broad-based economic growth, food security and pov-

erty reduction in Zambia. Organizations such as the International Maize and Wheat Improvement

Center (CIMMYT) and the International Institute of Tropical Agriculture (IITA) have been work-

ing with the Zambia Agricultural Research Institute (ZARI) to develop and disseminate improved

maize varieties. Private seed companies such as Panner, SeedCo and Maize Research Institute

(MRI) have also invested in maize breeding. According to Kalinda et al., (2014), more than 50

improved maize varieties have been released in Zambia.

A number of studies have looked at the welfare impacts of improved maize varieties (Kumar,

1994; Mason & Smale, 2013; Smale & Mason, 2014), but most of the previous studies have not

measured the direct impacts on household food security. An exception is the paper by Khonje,

Manda, Alene, and Kassie (2015) that looks at the impacts of improved maize in eastern Zambia,

including one food security variable. They find that improved maize is important in increasing

income and reducing poverty. However, using a single measure of household food security, they

find rather a weak association of improved maize adoption with household food security. A study

by Kassie, Jaleta, and Mattei (2014) examined the impact of improved maize varieties on food

security in Tanzania and found that adoption of improved maize varieties reduced food insecurity

among adopters of improved maize. However this study does not consider the amount of calories

consumed by a particular household in measuring the food security status of the households. Baba-

tunde and Qaim (2010) have shown that this is an important measure of food security. This paper

extends the studies mentioned above by explicitly examining the impact of adoption of improved

maize varieties on household food security in eastern Zambia

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using several food security mea-

sures that capture various aspects of food security. In addition, instead of using total household

consumption expenditure as used in Khonje et al. (2015), this paper uses food expenditure as a

measure of food security. The amount or share of money spent on food (food expenditure) by a

household is an important measure of food security as it is an indicator of economic vulnerability,

that is, it approximates the losses experienced when food prices rise (Lele, Masters, Kinabo, &

Meenakshi, 2016; Moltedo, Troubat, Lokshin, & Sajaia, 2014; Smith & Subandoro, 2007). The

indicator is also attractive because the data can easily be collected and is easier to measure accu-

rately than other indicators (Lele et al., 2016).

The paper adds to existing literature on adoption and food security in the following ways. First,

unlike other semiparametric impact evaluation methods, this study uses the inverse probability

weighted regression adjustment (IPWRA) estimation method (Imbens & Wooldridge, 2009;

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