Utilization of calico plant (Alternanthera bettzickiana (Regel) Voss. as bio-organic manure through vermicomposting

AbstractCalico plant (Alternanthera bettzickiana (Regel) Voss., an invasive weed, is now a major weed in different upland crops and waste lands in Kerala, India. The studies were conducted on vermicomposting of A. bettzickiana mixed with and without banana pseudostem in various proportions (v/v) (8:1, 4:1, 2:1, 1:1 and weed alone) along with cow dung. There was an increase in electrical conductivity and total contents of macronutrients (N, P and K) and micronutrients (Fe, Zn and Cu) along with a decrease in pH, total organic carbon (TOC) and C/N ratio after vermicomposting. Use of weed biomass alone and in combination with pseudostem (8:1) had significantly higher N, P content and earthworm growth and lower TOC and C/N ratio. Treatments with higher proportion of pseudostem produced compost with higher TOC, C/N ratio and K content. Compost recovery to the extent of 47 and 45.3% was observed in vermi-reactors with weed alone and mixed material (8:1), respectively, along with a lower rate of recovery (34%) in uniformly mixed proportion of weed + pseudostem (1:1). Increase in nutrient content and growth of earthworms in all the vermi-reactors indicated the suitability of A. bettzickiana for vermicomposting, which might be an effective way of utilizing the invasive weed biomass as bio-organic manure.