The value of soil enrichment media generated from invasive alien plant biowaste

The value of soil enrichment media generated from invasive alien plant biowaste
Yusuf Adam, Syd Ramdhani, Sershen Naidoo
University of KwaZulu Natal

Globally,  numerous  organisations  are  actively  involved  in  controlling  many  invasive  alien  plant species that threaten biodiversity. The plant biowaste generated by removal of these species is generally disposed of, even though it represents a potential resource for soil enrichment through composting. This study investigated the value of soil enrichment media generated from biowaste of four invasive species in South Africa (Acacia podalyriifolia, Hedychium gardnerianum, Litsea glutinosoa and Tithonia diversifolia). These species were harvested and then tested for allelopathic effects: leachates produced from biomass of all four taxa had no marked effects on Zea mays (maize) and Pisum sativum (pea) seed germination. Soil enrichment media was then produced by composting these species in four combinations (one woody with one herbaceous species); a commercial compost was also assessed for comparative purposes. The primary nutrient content of these media was determined prior to their use in plant growth studies involving Z. mays and P.sativum. All experimental media exhibited similar or higher potassium content than the commercial type but lower phosphorus, and except for one combination, lower nitrogen levels. Growth of both crop species on three of the experimental media was comparable with the commercial type. However, the effect of the various biowaste media on growth differed between maize and pea, with maize showing an overall better response. The results suggest that biowaste of selected invasive alien plant species can be used as a substitute for commercial soil enrichment media when growing crops like maize and pea, with little to no decline in yield.