On-Farm Crop Species Richness Is Associated with Household Diet Diversity and Quality in Subsistence- and Market-Oriented Farming Households in Malawi.

BACKGROUND: On-farm crop species richness (CSR) may be important for maintaining the diversity and quality of diets of smallholder farming households.

OBJECTIVES: The objectives of this study were to 1) determine the association of CSR with the diversity and quality of household diets in Malawi and 2) assess hypothesized mechanisms for this association via both subsistence- and market-oriented pathways.

METHODS: Longitudinal data were assessed from nationally representative household surveys in Malawi between 2010 and 2013 (n = 3000 households). A household diet diversity score (DDS) and daily intake per adult equivalent of energy, protein, iron, vitamin A, and zinc were calculated from 7-d household consumption data. CSR was calculated from plot-level data on all crops cultivated during the 2009-2010 and 2012-2013 agricultural seasons in Malawi. Adjusted generalized estimating equations were used to assess the longitudinal relation of CSR with household diet quality and diversity.

RESULTS: CSR was positively associated with DDS (β: 0.08; 95% CI: 0.06, 0.12; P < 0.001), as well as daily intake per adult equivalent of energy (kilocalories) (β: 41.6; 95% CI: 20.9, 62.2; P < 0.001), protein (grams) (β: 1.78; 95% CI: 0.80, 2.75; P < 0.001), iron (milligrams) (β: 0.30; 95% CI: 0.16, 0.44; P < 0.001), vitamin A (micrograms of retinol activity equivalent) (β: 25.8; 95% CI: 12.7, 38.9; P < 0.001), and zinc (milligrams) (β: 0.26; 95% CI: 0.13, 0.38; P < 0.001). Neither proportion of harvest sold nor distance to nearest population center modified the relation between CSR and household diet diversity or quality (P ≥ 0.05). Households with greater CSR were more commercially oriented (least-squares mean proportion of harvest sold ± SE, highest tertile of CSR: 17.1 ± 0.52; lowest tertile of CSR: 8.92 ± 1.09) (P < 0.05).

CONCLUSION: Promoting on-farm CSR may be a beneficial strategy for simultaneously supporting enhanced diet quality and diversity while also creating opportunities for smallholder farmers to engage with markets in subsistence agricultural contexts.