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Feed the Future Innovation Lab for Collaborative Research on Horticulture

Managing nematodes and soil health

Project Title: Integrated and Scalable Nematode-Soil Health Management for Smallholder Potato Farming Systems

Target Country: Guatemala

Principal Investigator: Brent Sipes, University of Hawaiʻi at Mānoa


Project Description

Plant-parasitic nematodes and soil degradation on smallholder farms reduce yields and limit smallholder food security. Current smallholder farming practices can exacerbate soil degradation and losses to nematodes. Such nematodes are prevalent in soils that are biologically and nutritionally degraded, which are at the root of global challenges in poverty alleviation, malnutrition, and food insecurity. Integrated pest management (IPM) and improving soil health are foundational for developing sustainable smallholder agroecosystems.

The smallholder farmers of the Western Highlands of Guatemala face yield losses from cyst, root-knot, root-lesion, and spiral plant-parasitic nematodes. Root-knot, cyst and root-lesion nematodes are the top harmful nematodes globally and are the most serious nematode types affecting potato in this region. Management is a challenge because nematodes have broad host ranges, populations are often mixtures of species, few crops have broad-spectrum resistance, and chemical nematicides are either not preferred, expensive, or legally restricted.

Considering the mechanisms by which nematodes cause yield loss and the fact the smallholders often farm degraded soils, sustainable management of plant-parasitic nematodes is best achieved through a soil health management approach. For smallholder farmers, strategies that improve soil health and reduce population densities of harmful nematodes within a framework of sustainable intensification and conservation agriculture practices are most logical. Integrating soil health knowledge into smallholder agriculture will reduce the impact of nematodes and other pests on income, food and nutritional security. Our goal is to assist smallholder farmers in adopting integrated technologies for nematode and soil health management, to achieve sustainable yields that provide income, food and nutritional security.

With smallholder potato farmers in the Western Highlands of Guatemala, our transdisciplinary research team will demonstrate and advocate for integrated practices of cover cropping, intercropping, soil amendment, biopesticides, and crop resistance. We will conduct replicated trials to demonstrate effectiveness and engage smallholders in on-farm tests of desirable practices. Trials will encompass different socio-cultures represented by farms near San Macros with Andisol soils and farmers near Huehuetenango with Mollisol soils. The research team will monitor and collect data from the trials focusing on nematode control, economics, and soil health. Smallholder farmers will record on-farm potato yield. Using cognitive mapping, the transdisciplinary team will modify treatments where necessary and design educational plans for the incorporation of climate-smart practices that integrate nematode and soil health management into potato and potato-vegetable cropping. Field days and educational activities will be held to motivate smallholder communities towards adoption of desired practices for managing nematode and soil health.