Utility tag, farming elements and ITK for sustainable management of weeds in changing climate.

A predominance of small holder farms in Asia offers scope for using component elements in a farming system for sustainable management of weeds that behave invasive in a changing climate. Altered precipitation, evaporation and temperature patterns due to climate change have resulted in weed flora shifts in northern coastal districts of Tamilnadu state, India. In particular, there has been a preponderance of invasive alien species such as Leptochloa chinensis (L.) and Marsilea quadrifolia L. in wetlands, Trianthema portulacastrum L. in uplands and Eichhornia crassipes Mart. Solms in aquatic systems. Research undertaken at Annamalai University in India is providing some alternative solutions to manage these problematic weeds. Innovative use of fish culture and poultry rearing in rice fields was shown to compliment weed control through 400 on-farm experiments, with biomass reductions of invasive alien species ranging from 31 to 38 per cent, in these districts. Similarly, using goats for off-season grazing reduced the biomass of weeds in upland crops. For example, biomass of the dominant T. portulacastrum declined by 23 to 29 per cent in 500 on-farm participatory experiments. Involving pigs for burrowing the puddled fields and addition of Tamarind husk complimented control of rice weeds especially nut sedge, which was reduced by 61 per cent. The invasive weed E. crassipes in aquatic systems was controlled in seasonal waterbodies within a season, by innovative and integrated use of insect agent (Neochetina eichhorniae) and plant product of Coleus amboinicus L. Utility modes for consuming the extensive biomass of E. crassipes have also been compared (viz., manure, cattle feed and nanofiber extraction). Results indicate that manurial use and tempo mediated extraction of nanofibers offers an innovative tag of utility for management of this weed