Vermicomposting of Pleurotus eryngii spent mushroom substrates and the possible mechanisms of vermicompost suppressing nematode disease caused by Meloidogyne incognita
It is indicated that vermicomposting is a promising technology for recycling of P. eryngii SMS disposal and a practical manner for control of the diseases caused by root-knot nematodes.
Abstract
The mushroom industry produces a large amount of spent mushroom substrate (SMS), which requires a large geographical footprint and causes pollution. Vermicomposting is a low-cost technology for its value in recycling of organic wastes and production of beneficial organic fertilizers. In this study, the changes of physicochemical properties was characterized during vermicomposting of <i>Pleurotus eryngii</i> SMS with cow dung (CD) as amendment. The efficiency and possible mechanisms of vermicompost suppressing disease induced by <i>Meloidogyne incognita</i> was also investigated. Six combinations with different ratios of SMS and cow dung (CD) was included in the vermicomposting using <i>Eisenia fetida</i>. Effect of vermicompost against disease induced by <i>M. incognita</i> on tobacco was conducted under greenhouse condition. And the possible mechanisms of vermicompost suppressing <i>M. incognita</i> was investigated by evaluated the species diversity of nematode-trapping fungi (NTF) in soil, and the defense response enzymes in tobacco. The combination of 65% SMS +35% CD was more suitable for vermicomposting, in which the highest vermicompost production (57%) and earthworm biomass increment (268%) were achieved. Additionally, the reduction in pH, total organic carbon, carbon: nitrogen ratio, and the pronounced elevation in four overall nutrient status were also observed. Soil amended with vermicompost (100:1 w/w) showed 61% control efficiency against nematode disease caused by <i>M. incognita</i> on tobacco, which significantly higher than that of the normal compost (24%). Comparing to the normal compost, the potential mechanism of vermicompost suppressing <i>M. incognita</i> could be rely on promoting species diversity of NTF in soil and enhancing the activities of the defense response enzymes in tobacco plant. Our findings indicate that vermicomposting is a promising technology for recycling of <i>P. eryngii</i> SMS, and the resulting vermicompost as organic fertilizer can be sued for management of the diseases caused by root-knot nematodes. This study establish a sustainable avenue for <i>P. eryngii</i> SMS disposal and a practical manner for controlling pathogens.