Subsurface water retention technology with adapted crops for sandy soil productivity and carbon sequestration
A field-validated approach combining subsurface water retention membranes with adapted food crops (maize, cowpea) to boost yields and carbon sequestration on sandy soils. Trials across 11 farms demonstrated up to 170% increases in maize grain yield, cob number, cob weight, and stover biomass, with cowpea also showing higher biomass and grain yields versus controls.
Overview
This solution addresses the dual challenge of low productivity and limited carbon storage on sandy soils by combining subsurface water retention technology (SWRT) with carefully selected adapted food crops. Sandy soils typically struggle to retain water and nutrients, limiting agricultural output and contributing to soil degradation. By installing subsurface membranes that hold water and nutrients in the root zone, and pairing this infrastructure with deep-rooted, high-biomass crops, the approach sustains food and biomass production while enhancing soil organic matter and carbon sequestration.
The technology has been validated in multi-farm field trials on sandy soils, demonstrating substantial gains in both maize and cowpea performance. It offers a practical pathway for farmers, agricultural development programs, and sustainability initiatives working in arid and semi-arid regions to improve food security, restore soil health, and capture atmospheric carbon.
Technical specifications
Core technology:
- Subsurface water retention membranes installed beneath the root zone to retain water and nutrients that would otherwise leach through sandy soil
- Adapted crop selection prioritizing varieties with deep root systems and high biomass production potential, including maize and cowpea
- Combined water-nutrient conservation strategy designed to reduce irrigation requirements while sustaining yields
Validated performance across 11 farms:
- Maize grain yield increased by up to 50% compared to control plots
- Cob number increased by up to 100%
- Cob weight increased by up to 150%
- Maize stover biomass increased by up to 170%
- Cowpea demonstrated higher biomass and grain yield versus control on six farms
Trial design: Each farm included two 200 m² plots with subsurface membranes alongside a same-sized control plot, enabling direct performance comparison under real farming conditions.
Technology readiness level
The technology has progressed beyond laboratory and controlled testing into multi-farm field validation. Eleven on-farm trials have been completed with consistent yield and biomass improvements documented across both maize and cowpea. Future validation work will expand farmer recruitment, conduct regional needs assessments to identify priority adapted crops, and further evaluate the carbon sequestration potential of the system under reduced irrigation. The approach is positioned for broader scaling and partnership-based deployment in sandy soil regions.
About Jomo Kenyatta University of Agriculture and Technology
Jomo Kenyatta University of Agriculture and Technology (JKUAT) is a large, comprehensive public research university in Juja, about 36 kilometres northeast of Nairobi, with a strongly applied, technology-oriented character. Its main campus and additional campuses extend access across Kenya, while its position on the Nairobi–Thika corridor places corporate R&D teams near a major commercial and innovation ecosystem. Research reaches external users through a Research, Production and Extension division, university–industry liaison and intellectual-property functions, the JKUAT Industrial Park, innovation funding, and collaborations with companies, government, and research organizations. Funding includes Kenya’s National Research Fund and international development, philanthropic, and industry partners. Commercialization support covers IP evaluation, protection, licensing, incubation, and startup partnerships.
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