A Geospatial Approach to Assessing the Impact of Agroecological Knowledge and Practice on Crop Health in a Smallholder Agricultural Context

Abstract

In the context of food insecurity in resource-poor settings, agroecology (AE) has emerged as an important approach promoted for improving crop productivity, yet few studies have demonstrated how a combination of agroecological methods can improve crop health and thereby crop productivity. Using a geospatial approach, this study investigated whether agroecological practices can improve crop health in smallholder contexts. We compared leaf area indexes (LAIs) of crops on AE and non-AE farms and prospectively predicted the impact of AE using vegetation indexes (VIs). We found that crops on AE farms produced higher average growing season LAIs for maize and pigeon peas (1.28 m²/m²) and maize and beans (1.29 m²/m²) farms compared to 0.97 m²/m² and 0.80 m²/m², respectively, for the same crops on the non-AE farms. The higher LAIs suggest that the combination of farming strategies practiced on the AE farms produced healthier crops on AE farms. Random forest regression prospective predictions generated statistically significant higher LAIs for maize and beans (R² = 0.90, root mean square error [RMSE] = 0.32 m²/m²) and maize and pigeon peas (R² = 0.88 m²/m², RMSE = 0.42 m²/m²) on the AE farms, but predictions for the non-AE farms were not statistically significant. The findings demonstrate that combining AE strategies can potentially improve crop productivity to enhance household food security and income in smallholder contexts.

在资源贫乏地区粮食短缺的情况下, 生态农业已成为提高作物生产力的重要方式。但鲜有研究能表明, 生态农业的多方法组合如何改善作物健康、提高生产力。本文采用地理空间方法, 研究了生态农业实践是否能改善小型农业的作物健康。比较了生态农场和非生态农场的作物叶面积指数（LAI）, 并利用植被指数预测了生态农业的影响。在作物生长期, 生态农场的玉米和木豆的平均LAI为1.28 m²/m²、玉米和豆类的平均LAI为1.29 m²/m², 高于非生态农场的同类作物（平均LAI分别为0.97 m²/m²和0.80 m²/m²）。高LAI表明, 生态农场的组合耕作策略, 为生态农场生产了更健康的作物。随机森林回归预测了生态农场的高LAI：玉米和豆类的R²为0.90（均方根误差RMSE为0.32 m²/m²）、玉米和木豆的R²为0.88 m²/m²（RMSE为0.42 m²/m²）。但是, 对非生态农场的预测不具备统计显著性。结果表明, 多种生态农业策略的组合, 可能会提高作物生产力, 改善小型农业家庭的粮食安全和收入。

En el contexto de la inseguridad alimentaria dentro de entornos de recursos mínimos, la agroecología (AE) aparece como un enfoque importante para mejorar la productividad de las cosechas, aunque pocos son los estudios que hayan demostrado cómo una combinación de métodos agroecológicos pueda mejorar la condición sanitaria de los cultivos y consecuentemente su productividad. Usando un enfoque geoespacial, este estudio investigó si las prácticas agroecológicas pueden mejorar la salud de los cultivos en los contextos de pequeños cultivadores. En el estudio se compararon los índices de área foliar (LAIs) de los cultivos, en granjas con y sin AE, y se predijo de manera prospectiva el impacto de AE con los índices de vegetación (VIs). Encontramos que los cultivos en granjas AE rindieron LAIs más altos que el promedio durante el período vegetativo para los casos del maíz y los guandules (1,28 m²/m²) y el maíz y fríjoles (1,29 m²/m²), rendimientos comparados con el 0,97 m²/m² y 0,80 m²/m² obtenidos, respectivamente, para los mismos tipos de cultivos en granjas sin AE. Los LAIs más altos sugieren que la combinación de las estrategias agrícolas practicadas en las granjas AE produjeron cosechas más sanas en esas granjas AE. Las predicciones prospectivas de regresión aleatoria forestal generaron LAIs más altos estadísticamente significativos para el maíz y las judías (R² = 0,90), error cuadrático medio [RMSE] = 0,32 m²/m²), y maíz y los guandules (R² = 0,88 m²/m², RMSE = 0,42 m²/m²) en granjas AE, pero las predicciones para las granjas sin AE no fueron estadísticamente significativas. Los descubrimientos demuestran que al combinar las estrategias AE potencialmente se puede mejorar la productividad de los cultivos para aumentar la seguridad alimentaria y los ingresos de los hogares, en contextos de pequeños agricultores.

Key Words:

• agroecology
• agroecosystems
• crop health
• Malawi
• random forest regression

关键词:

• 生态农业
• 农业生态系统
• 作物健康
• 马拉维
• 随机森林回归。

Palabras clave:

• agroecología
• agroecosistemas
• Malawi
• regresión forestal aleatoria
• salud de los cultivos

Acknowledgments

The authors are grateful to all the farmers on whose farms the experiments were conducted. We are also thankful to the village chiefs and headmen for granting us permission to enter and work in their villages. The authors are also thankful to Gladson Simwaka, the research assistant during the research, and the staff of the Soils, Food and Healthy Communities organization, our partners in Malawi. Finally, we are also thankful to two anonymous reviewers who reviewed this article.

Notes

1 In the study context, a village area is used to describe a large area with smaller villages usually of farming households.

Additional information

Funding

We are also grateful to the International Development Research Centre (IDRC) for the Doctoral Awards (IDRA 2018, 108838-013) and the Micha and Nancy Pazner Fieldwork Award for their financial support for the doctoral field work of Daniel Kpienbaareh. Funding was also provided by the National Science Foundation, Grant/Award Number: 1852587; Natural Sciences and Engineering Research Council of Canada, Grant/Award Number: 523660-2018; German Federal Ministry of Education and Research; and the Research Council of Norway.

Notes on contributors

Daniel Kpienbaareh

DANIEL KPIENBAAREH is an Assistant Professor of Geography at Illinois State University, Normal, IL 61790. E-mail: [email protected]. His research interests include geospatial applications including precision agriculture, natural resource management, agroecology and other regenerative farming approaches, participatory GIS, smallholder agriculture, and sub-Saharan Africa.

Jinfei Wang

JINFEI WANG is a Professor of Geography at the University of Western Ontario, London ON N6G 5C2, Canada. E-mail: [email protected]. Her research interests include algorithms for automatic linear and other man-made feature detection from images, methods for GIS feature extraction and land use/cover change detection in urban environment using multispectral and hyperspectral data, and applications of radar and optical remote sensing and GIS for environmental change analysis near large rivers and mountains and in marsh and mangrove wetlands.

Isaac Luginaah

ISAAC LUGINAAH is a Professor of Geography at the University of Western Ontario, London, ON N6G 5C2, Canada. E-mail: [email protected]. His research interests include environment and health, air pollution, GIS and health, food security, and HIV/AIDS.

Rachel Bezner Kerr

RACHEL BEZNER KERR is a Professor of Development Sociology at Cornell University, Ithaca NY 14853. E-mail: [email protected]. Her current research interests include socioeconomic viability of agroecological practices across Africa; landscape-level impacts of agroecology on biodiversity and ecosystems; participatory climate change adaptation in Malawi, including forest regeneration; policies to support agroecology transitions in Malawi; and social and ecological impacts of biodiversity in agriculture-synthesis study.

Esther Lupafya

ESTHER LUPAFYA is the Executive Director of the Soils, Food and Healthy Communities nonprofit organization in Ekwendeni, Malawi. E-mail: [email protected]. Her research interests include community mobilization, project management, agroecology, nutrition, health, and food security.

Laifolo Dakishoni

LAIFOLO DAKISHONI is the Deputy Executive Director of the Soils, Food and Healthy Communities nonprofit organization in Ekwendeni, Malawi. E-mail: [email protected]. His research interests focus on community mobilization, project management, agroecology, nutrition, health, and food security.