Effects of termite sheetings on soil properties under two contrasting soil management practices

Soil organic matter (SOM) dynamics and termite activity have now been widely accepted as key players for improving soil properties in tropical agro-ecosystems. Numerous studies have described environmental impacts of aboveground termite mounds, while few data are available on temporary structures built for food foraging, called termite sheetings. The effects of termite activity on soil properties resulting from organic matter (OM) amendment under two contrasting management practices were studied in similar pedological and climatic conditions in Southern India (Auroville). Our results showed an increase in bio-available nutrients (K, Mg and P), organic carbon (OC) content, cationic exchange capacity (CEC), exchangeable base cations and water pH in the termite sheetings compared to the underlying and reference soils, in the organic tilled field. On the other hand, only bio-available K increased in the permanent raised beds. Aggregation processes were improved in termite sheetings for the organic tilled field, as the amounts of macroaggregates (250 mu m-2 mm) and protected microaggregates increased, whereas the amount of free microaggregates (50-250 mu m) decreased. Moreover, termite activity favoured SOM storage in termite sheetings by increasing OC content in each aggregate fraction, while no differences were observed in the permanent raised beds. Our study demonstrates that termite activity can improve nutrient availability, carbon storage and pH conditions in agro-ecosystems but that the magnitude of the effect likely depends on the agronomic practices in use