A nation that rebuilds its soils rebuilds itself- an engineer's perspective (2022)
Journal Article
Johnson, K. L., Gray, N. D., Stone, W., Kelly, B. F., Fitzsimons, M. F., Clarke, C., …Gwandu, T. (2022). A nation that rebuilds its soils rebuilds itself- an engineer's perspective. Soil security, 7, Article 100060. https://doi.org/10.1016/j.soisec.2022.100060

Nations can build and rebuild degraded soils to help address climate change and potentially improve the nutritional content of food if we change policies that allow the addition of safe mineral and organic wastes to soil. We present a framework that... Read More about A nation that rebuilds its soils rebuilds itself- an engineer's perspective.

Waste to resource: use of water treatment residual for increased maize productivity and micronutrient content (2021)
Journal Article
Gwandu, T., Blake, L., Nezomba, H., Rurinda, J., Chivasa, S., Mtambanengwe, F., & Johnson, K. (2022). Waste to resource: use of water treatment residual for increased maize productivity and micronutrient content. Environmental Geochemistry and Health, 44(10), 3359-3376. https://doi.org/10.1007/s10653-021-01100-z

Soil degradation, which is linked to poor nutrient management, remains a major constraint to sustained crop production in smallholder urban agriculture (UA) in sub-Saharan Africa (SSA). While organic nutrient resources are often used in UA to complem... Read More about Waste to resource: use of water treatment residual for increased maize productivity and micronutrient content.

The microbiology of rebuilding soils with water treatment residual co‐amendments: Risks and benefits (2021)
Journal Article
Stone, W., Lukashe, N. S., Blake, L. I., Gwandu, T., Hardie, A. G., Quinton, J., …Clarke, C. E. (2021). The microbiology of rebuilding soils with water treatment residual co‐amendments: Risks and benefits. Journal of Environmental Quality, 50(6), 1381-1394. https://doi.org/10.1002/jeq2.20286

Water treatment residuals (WTR) are sludges from the potable water treatment process, currently largely destined for landfill. This waste can be diverted to rebuild degraded soils, aligning with the UN's Sustainable Development Goals 12 (Consumption... Read More about The microbiology of rebuilding soils with water treatment residual co‐amendments: Risks and benefits.

Better Together: Water Treatment Residual and Poor-Quality Compost Improves Sandy Soil Fertility (2019)
Journal Article
Clarke, C. E., Stone, W., Hardie, A. G., Quinton, J. N., Blake, L. I., & Johnson, K. L. (2019). Better Together: Water Treatment Residual and Poor-Quality Compost Improves Sandy Soil Fertility. Journal of Environmental Quality, 48(6), 1781-1788. https://doi.org/10.2134/jeq2019.03.0147

Water treatment residual (WTR) is an underused clean water industry byproduct, generally disposed to landfill. This study assesses the benefits and risks of ferric-WTR as a soil amendment or co-amendment for plant growth in a nutrient-poor sandy soil... Read More about Better Together: Water Treatment Residual and Poor-Quality Compost Improves Sandy Soil Fertility.