Vermicomposting transforms allelopathic parthenium into a benign organic fertilizer

Detoxification of parthenium (Parthenium hysterophorus) and its metamorphosis into an organic fertilizer and biopesticide

“…But it is not yet established whether vermicompost derived from plants, more so from toxic and allelopathic plants like parthenium, can be as benign and effective an organic fertilizer as manure-derived vermicomposts are. In our recent studies (Gajalakshmi and Abbasi 2002; Hussain et al 2016a, b) it was seen that soil augmented with parthenium vermicompost had enabled better germination success of four species of food plants compared to the control soil. But will the beneficial effect extend to plant growth, fruit yield, and quality of the fruit?…”

“…Due to the absence of any effective natural enemies and due to its allelopathic nature, large seed bank, and fast growth rate, parthenium grows luxuriantly all through the year, infesting millions of hectares of land masses including agricultural fields, parks, orchards, railway tracks, and other open areas (Wiesner et al 2007; Nigatu et al 2010; Qureshi et al 2014). This proves disastrous in terms of monopolizing of space and nutrients by parthenium at the expense of other vegetation, consequent loss of biodiversity, and associated ecological imbalances (Hussain et al 2016a, b). Parthenium’s dominance over other vegetation is fostered by the presence of allelopathic compounds in parthenium, especially parthenin, hysterin, ambrosin, and flavonoids (Maishi et al 1998; Khan and Abbasi 1998; Knox et al 2011; Patel 2011; Kaur et al 2014).…”

“…These compounds are leached when dew or rain falls on parthenium (Abbasi and Abbasi 2011), and reach the underlying soil. There they cause toxicity, discouraging the growth of other vegetation in the vicinity of parthenium, thereby aiding and abetting the spread of parthenium monocultures (Hussain et al 2016a, b). …”

“…Efforts made across the world to find persistent methods of controlling parthenium by way of mechanical, chemical, or biological means, have at best achieved only partial and temporary success (Manoj 2014; Hussain et al 2016a). The weed has never been eradicated from any country and its spread in all the tropical and sub-tropical regions of the world is only increasing with time.…”

“…When a substrate is vermicomposted, it converts the latter into fine peat-like material and transforms some of its nutrients into more bioavailable forms (Hussain et al 2015, 2016a, b. The vermicompost acquires several species of microflora, besides hormones and enzymes as it passes though the earthworms' gut (Pramanik et al 2007; Ievinsh 2011).…”