Purdue Improved Crop Storage

Purdue Improved Crop Storage. It is an hermetic storage technology designed to protect harvested cereal grains, primarily maize, from insect pests and mold without using synthetic pesticides. Developed at Purdue University in the late 1980s, the system utilizes airtight containers to create a modified atmosphere that suffocates infesting insects. The technology has been widely promoted across Sub-Saharan Africa and other developing regions by organizations like the United States Agency for International Development and the Bill & Melinda Gates Foundation to reduce post-harvest losses and improve food security.

Overview

The core principle relies on creating an oxygen-depleted, carbon dioxide-rich environment within a sealed container, which is lethal to storage pests like the larger grain borer and the maize weevil. This method prevents both insect damage and the growth of mycotoxin-producing fungi, thereby preserving grain quality and nutritional value. The system is particularly targeted at smallholder farmers in regions where access to chemical fumigants like phosphine is limited or where pesticide misuse poses health and environmental risks. Successful implementation has been documented in countries including Kenya, Ghana, Malawi, and Mozambique, often through partnerships with national agricultural extension services and non-governmental organizations.

Development and Technology

The technology was pioneered by entomologist Larry Murdock and his team at Purdue University's Department of Entomology. Initial research focused on the physiological effects of low-oxygen atmospheres on insect pests prevalent in stored maize in West Africa. The standard PICS bag consists of two layers of high-density polyethylene liners enclosed within a third, woven polypropylene sack, creating a robust hermetic seal. When properly closed, the metabolic activity of insects and the grain itself rapidly consumes residual oxygen, typically achieving a fatal atmosphere within days. This design is a significant evolution from traditional methods like jerrycans or mud silos, offering a more reliable and scalable solution.

Adoption and Impact

Widespread adoption has been driven by extensive field validation and promotion campaigns coordinated by the Purdue International Programs in Agriculture. Major funding from the United States Agency for International Development under the Feed the Future initiative and the Bill & Melinda Gates Foundation has enabled large-scale dissemination. Studies, including those published in the Journal of Stored Products Research, have consistently shown the technology can reduce grain losses by over 90%, significantly boosting household income and food availability. The system has also empowered women farmers, who are often primarily responsible for post-harvest management, by providing a safer, more effective storage method. Its success contributed to the development of the broader Purdue Improved Cowpea Storage project for legumes.

Implementation and Training

Deployment involves a comprehensive training model for farmers and local entrepreneurs, often facilitated by partners like Catholic Relief Services and TechnoServe. Training modules cover proper bag filling, sealing techniques using twine or rope, and methods for inspecting for leaks. A critical component is the development of local supply chains for the manufacture and sale of the specialized bags, creating income opportunities for agro-dealers. Extension agents use demonstration plots and farmer field schools to showcase the technology's benefits compared to conventional storage in jute sacks or application of diatomaceous earth. This approach has been successfully replicated across diverse agro-ecological zones from the Sahel to East Africa.

Variations and Related Systems

The original design for maize has inspired adaptations for other crops, most notably the Purdue Improved Cowpea Storage system, which uses triple-layer bags to protect cowpeas from the cowpea bruchid. Other related hermetic technologies include the GrainPro Super Grain Bag, the IRRI Super Bag, and metal silos promoted by organizations like the Food and Agriculture Organization. The fundamental principle also applies to larger-scale storage using hermetic cocoons or silo bags on commercial farms. Research continues into integrating oxygen absorbers and developing low-cost sensors to monitor atmospheric conditions within the sealed containers, further optimizing the technology.

Category:Agricultural technology Category:Post-harvest losses Category:Purdue University