RESEARCH EXPLORES SUGARCANE WASTE AS SUSTAINABLE FERTILISER FOR FOOD SECURITY

Sugarcane filter cake could provide a sustainable alternative for improving the production of traditional vegetables while reducing the environmental impact associated with agricultural waste, according to University of Zululand researcher, Sbonelo Dlamini.

She presented this at the Annual Young Scientist Conference (AYSC) held at iYunivesithi Walter Sisulu’s Mthatha campus from 13 – 15 September 2026 under the theme: Assuring Sustainable Water Availability and Safe Sanitation Systems to achieve the goals of agenda 2063.

Dlamini said the research was motivated by the persistent challenges of food insecurity and malnutrition in many sub-Saharan African communities, as well as the need for more sustainable agricultural production.

“Traditional vegetables have attracted increasing interest because they can contribute to food and nutrition security, particularly in communities where resources such as water are limited,” said Dlamini.

The study investigated the use of sugarcane filter cake, a by-product generated during the clarification of sugarcane juice, as an organic fertiliser in the production of a traditional leafy vegetable.

According to Dlamini, filter cake contains organic matter and nutrients that can improve plant growth, soil organic carbon, microbial activity and soil structure, making it potentially useful as an agricultural input. However, the improper disposal of filter cake can create environmental challenges.

“When sugarcane filter cake is improperly disposed of, it can result in unpleasant odours and the formation of acidic leachate, which can contribute to environmental pollution, farmland degradation and contamination of surface and groundwater,” said Dlamini.

The study therefore explored whether the waste product could instead be converted into a useful agricultural resource, contributing to a more circular and sustainable approach to food production.

Dlamini and the research team tested different application rates of sugarcane filter cake and compared their effects with a control treatment and an inorganic Nitrogen, Phosphorus, Potassium (NPK) fertiliser.

The researchers monitored the plants at two, four and six weeks, measuring characteristics including plant height, number of leaves and fresh leaf weight. They also assessed physiological responses and compounds associated with the nutritional and antioxidant properties of the leaves.

The findings showed that the response of the plants varied according to the amount and type of fertiliser applied.

“The  30 kg/ha filter cake treatment showed a strong response in physiological performance, while the 40 kg/ha treatment produced notable responses in some antioxidant compounds, including quercetin and proanthocyanidins,” she said.

The findings showed that inorganic NPK fertiliser, meanwhile, produced the highest fresh leaf weight and showed stronger responses for some compounds, including carotenoids.

Dlamini said the findings demonstrate that a higher fertiliser application rate does not necessarily produce better results across all plant characteristics.

“The fertiliser source and application rate shifted the profile of individual compounds rather than increasing all the compounds. This shows that the response was dose- and compound-specific,” said Dlamini.

The study therefore suggests that sugarcane filter cake has potential as an organic fertiliser, but that its application rate should be carefully selected according to the desired agricultural and nutritional outcomes.

Dlamini said the findings could contribute to efforts to address agricultural waste while supporting sustainable vegetable production.

By Anita Roji