In which method parthenium can be made into compost?

It is always recommended by the scientists to collect the parthenium biomass before flowering for making compost either by NADEP or open pit method. But it is not practically possible to collect only flowerless plants as all the stages of Parthenium are available at any time due to non-dormancy of seeds which may germinate on the availability of water. Therefore, farmers are bound to uproot every stage of Parthenium during weeding in their fields.