Combination of Mycorrhizal Symbiosis and Root Grafting Effectively Controls Nematode in Replanted Coffee Soil

Replanting for sustainable development is one of the critical missions of the coffee industry in the Daklak province, Vietnam. However, this plan has been faced with many difficulties including poor survival and growth rates due to the low nematode tolerance of young coffee plants in replanted fields. Mycorrhizal symbiosis and grafting have been applied separately but not yet resulted in the expected results of the replanting plan. Whether the combination of them would help managing nematode in the soil and consequently enhance the replanted efficiency is largely unknown. Mycorrhizal symbiosis was applied to Coffea canephora plants or/and grafted onto Coffea liberica rootstock, which were grown and compared to the untreated ones in both net-house-pots and the replanted plantation. The survival rate, growth indicators and the soil pathogens were monitored during the experimental periods. The combination of grafting and mycorrhiza symbiotic techniques significantly decreased the nematode densities in the replanted soil. As a result, the survival rate and growth indicators of the coffee in the replanted soil treated by the combined technique were better than treated by the two separate techniques. The results suggested that the combination of grafting and mycorrhiza symbiotic techniques would propose a potentially effective Pratylenchus coffeae and Meloidogyne incognita nematode management in replanted coffee fields in the Daklak province, Vietnam.